Biomedical subjects

R G Stock

Publications and source records attributed to R G Stock.

At least 19 recordsLinked to original sources

PubMed2001

Intraoperative planning and evaluation of permanent prostate brachytherapy: report of the American Brachytherapy Society.

PURPOSE: The preplanned technique used for permanent prostate brachytherapy has limitations that may be overcome by intraoperative planning. The goal of the American Brachytherapy Society (ABS) project was to assess the current intraoperative planning process and explore the potential for improvement in intraoperative treatment planning (ITP). METHODS AND MATERIALS: Members of the ABS with expertise in ITP performed a literature review, reviewed their clinical experience with ITP, and explored the potential for improving the technique. RESULTS: The ABS proposes the following terminology in regard to prostate planning process: *Preplanning--Creation of a plan a few days or weeks before the implant procedure. *Intraoperative planning--Treatment planning in the operating room (OR): the patient and transrectal ultrasound probe are not moved between the volume study and the seed insertion procedure. * Intraoperative preplanning--Creation of a plan in the OR just before the implant procedure, with immediate execution of the plan. *Interactive planning--Stepwise refinement of the treatment plan using computerized dose calculations derived from image-based needle position feedback. *Dynamic dose calculation--Constant updating of dose distribution calculations using continuous deposited seed position feedback. Both intraoperative preplanning and interactive planning are currently feasible and commercially available and may help to overcome many of the limitations of the preplanning technique. Dosimetric feedback based on imaged needle positions can be used to modify the ITP. However, the dynamic changes in prostate size and shape and in seed position that occur during the implant are not yet quantifiable with current technology, and ITP does not obviate the need for postimplant dosimetric analysis. The major current limitation of ITP is the inability to localize the seeds in relation to the prostate. Dynamic dose calculation can become a reality once these issues are solved. Future advances can be expected in methods of enhancing seed identification, in imaging techniques, and in the development of better source delivery systems. Additionally, ITP should be correlated with outcome studies, using dosimetric, toxicity, and efficacy endpoints. CONCLUSION: ITP addresses many of the limitations of current permanent prostate brachytherapy and has some advantages over the preplanned technique. Further technologic advancement will be needed to achieve dynamic real-time calculation of dose distribution from implanted sources, with constant updating to allow modification of subsequent seed placement and consistent, ideal dose distribution within the target volume.

Brachytherapy↗

PubMed2001

Defining the risk of developing grade 2 proctitis following 125I prostate brachytherapy using a rectal dose-volume histogram analysis.

OBJECTIVE: To determine the rectal tolerance for developing Grade 2 radiation proctitis after 125I prostate implantation based on the rectal dose-volume histogram. METHODS AND MATERIALS: Two hundred twelve patients with T1-T2 prostate cancer underwent 125I implantation without external beam irradiation. One month after the procedure, all patients underwent CT-based postimplant dosimetry (3-mm abutting slices). The rectal volumes, defined by an inner and outer wall, were determined from 9 mm above the seminal vesicles to 9 mm below the prostate apex. All doses were calculated by TG43 formalism. The prostate prescription dose was 160 Gy. A dose response analysis was undertaken for volumes of rectal tissue receiving a given dose. Dose levels examined were 80 Gy, 100 Gy, 120 Gy, 140 Gy, 160 Gy, 180 Gy, 200 Gy, 220 Gy, and 240 Gy. Grade 2 proctitis was defined as rectal bleeding occurring at least once a week for a minimum period of one month. The risk of proctitis was calculated using actuarial methods. For each dose level, a critical volume cutpoint was chosen to define a low and high volume group of patients. The cutpoint was determined based on two goals: minimizing thep value and finding a < or =5% risk of proctitis in the low volume group. Patients were followed from 12 to 61 months (median: 28 months) after implantation. RESULTS: Twenty-two patients developed Grade 2 proctitis: 14% within the first year, 72% between the first and second year, and 14% during the third year after the implant date. After the third year postimplantation, no cases of proctitis were reported. Proctitis was found to be significantly volume dependent for a given dose. The prescription dose (160 Gy) delivered to < or =1.3 cc of rectal tissue resulted in a 5% rate of proctitis at 5 years vs. 18% for volumes >1.3 cc (p = 0.001). Similar results were found for all doses examined. As the rectal volume receiving the prescription dose (160 Gy) increased, so did the proctitis rate: 0% for < or =0.8 cc, 7% for >0.8-1.3 cc, 8% for >1.3-1.8 cc, 24% for >1.8-2.3 cc, and 25.5% for >2.3cc (p = 0.002). CONCLUSIONS: Rectal dose-volume histogram analysis is a practical and predictive method of assessing the risk of developing Grade 2 proctitis after 125I prostate implantation. Delivered dose should be kept below defined rectal volume thresholds to minimize this risk. This information can allow one to decrease rectal morbidity by modifying prostate implant technique.

Aged↗

PubMed2001

Screening breast cancer patients for ATM mutations and polymorphisms by using denaturing high-performance liquid chromatography.

All 62 coding exons of the ATM gene, along with 10-20 bases of the intronic region flanking each exon, were screened for DNA base sequence alterations by using denaturing high-performance liquid chromatography (DHPLC) in a series of 52 breast cancer patients. Six (12%) of these patients exhibited a total of eight different novel germ-line mutations that do not represent common polymorphisms. Of these, three patients possessed four nonconservative missense mutations while two conservative missense and two synonymous mutations were detected in the other three patients. In addition, 43 patients were found to have a total of 141 DNA sequence variations representing 21 different common polymorphisms and rare variants. An analysis of the relationship between the presence of a novel ATM mutation and either patient demographics or tumor properties demonstrated a significant difference between African Americans (3/7 = 43%) and other ethnic groups (3/45 = 7%, P = 0.026). None of the other characteristics examined was found to be related to mutation status.

Adult↗

PubMed2001

Penile erectile function after permanent radioactive seed implantation for treatment of prostate cancer.

PURPOSE: We assess erectile function after prostate brachytherapy and analyze those factors affecting potency preservation. MATERIALS AND METHODS: A total of 416 patients treated from October 1990 to September 1998 with permanent radioactive seed implantation for T1 to T2 prostate cancer had erectile function assessed before and after treatment. Erectile function was assessed using the scoring system of 0-complete inability to have erections, 1-able to have erections but insufficient for intercourse, 2-can have erections sufficient for intercourse but considered suboptimal and 3-has normal erectile function. Implant dose was defined as the D90, which was the dose delivered to 90% of the gland on a dose volume histogram from the 1-month computerized tomography based dosimetric analysis. RESULTS: Pretreatment erectile function assessment revealed scores of 0 in 57 (14%), 1 in 46 (11%), 2 in 77 (18%) and 3 in 236 (57%) patients. In 313 patients who were potent with a score 2 or greater before therapy the actuarial freedom from any decrease in erectile function score was 64% and 30% at 3 and 6 years, respectively. The actuarial preservation of potency, with a score 2 or greater, was 79% and 59% at 3 and 6 years, respectively. The 2 factors found to have a significant negative effect on potency in univariate and multivariate analyses were high implant dose (D90 greater than 160 Gy. for I-125 and D90 greater than 100 Gy. for Pd-103) and a pretreatment erectile function score of 2 versus 3. CONCLUSIONS: The rate of potency preservation after brachytherapy is high, although a decrease occurs from 3 to 6 years. Pretreatment erectile dysfunction as well as higher implant dose are associated with greater impotency.

Adult↗

PubMed2000

The effect of disease and treatment-related factors on biopsy results after prostate brachytherapy: implications for treatment optimization.

BACKGROUND: Posttreatment prostate biopsy is a method of assessing local control after irradiation for prostate carcinoma. An analysis of the effect of disease- and treatment-related factors on biopsy results after prostate brachytherapy was performed to aid in patient selection and treatment optimization. METHODS: Two hundred sixty-eight patients underwent posttreatment prostate biopsy (6-8 cores) 2 years after brachytherapy alone without external beam irradiation. Follow-up ranged from 24 to 111 months (median, 43 months). Implants were performed using a real-time ultrasound guided technique with the isotopes (125)I in 186 and (103)Pd in 82 patients. Ninety-eight patients underwent hormonal therapy (HT) 3 months before and 2-3 months after implant. Implant dose was defined as the D90 (dose delivered to 90% of the gland from the dose volume histogram generated using 1-month computed tomography-based dosimetry). RESULTS: Overall, 89% of patients (238 of 268) had negative biopsies. A positive biopsy was a predictor of biochemical failure. Patients with a positive biopsy had a 5-year freedom from biochemical failure of 40% versus 76% for patients with a negative biopsy (P = 0.0003). Univariate and multivariate analysis found that risk group, HT, and implant dose significantly affected biopsy outcome. Patients with low risk features (prostate specific antigen [PSA] </= 10 ng/mL; Gleason score </= 6; and classification T2a or lower) (n = 104) had a negative biopsy rate of 95% versus 85% for those with high risk features (PSA > 10 ng/mL or Gleason score >/= 7 or classification T2b or higher) (n = 164) (P = 0.008). Hormonal therapy was associated with a negative biopsy rate of 98% versus 84% for implant alone (P = 0.003). Patients receiving a high implant dose (D90 >/= 140 grays [Gy] for (125)I or >/= 100 Gy for (103)Pd) (n = 174) had a negative biopsy rate of 95% versus 77% for those receiving a low dose (D90 < 140 Gy for (125)I or < 100 Gy for (103)Pd) (n = 87; P < 0.001). CONCLUSIONS: Biopsy results support the use of brachytherapy without external beam irradiation for patients with low risk features and highlight the importance of achieving an adequate implant dose.

Biopsy, Needle↗

PubMed2000

Body mass, age, and the APC I1307K allele in Ashkenazi Jewish prostate cancer patients.

The I1307K mutation of the adenopolyposis coli gene (APC), located on chromosome 5q21-q22, is associated with an increased risk of cancer in Ashkenazi Jews. In the present study, we analyzed age and body mass of Ashkenazi Jewish prostate cancer patients, with and without the APC I1307K mutation. Participants in our study were found through urology and radiation oncology clinics, and all eligible patients were asked to take part. A familial history was obtained by interview or self-report questionnaire. Histological confirmation of diagnosis was obtained for all subjects. The I1307K allele of the APC gene was detected by amplification of lymphocyte DNA from peripheral blood according to standard polymerase chain reaction (PCR) and dot blot procedures. We studied 135 Ashkenazi Jewish men with prostate cancer. The youngest was 49, the oldest 80, average age 68 +/- 6.88 (mean +/- SD). The older patients carrying the wild type APC allele tended to have a lower body mass than the younger ones (r = -.27, P =.002). Of 71 patients under 70 years old, 65 carried the wild type APC allele, and had a body mass index of 28. 7 +/- 4.23 kg/m(2). The six men under age 70 carrying the I1307K APC allele had a body mass index of 26.87 +/- 1.44 kg/m(2). The difference in body mass index of the two groups is significant (P =. 032, t test for unequal variance). Increased body mass is a prostate cancer risk factor, and hereditary prostate cancer is associated with younger patients. Therefore, our finding, that patients under age 70 carrying the I1307K allele are significantly thinner than those carrying the wild type allele, suggests that the APC I1307K allele is also a prostate cancer risk factor. Our results are in accord with other studies indicating that APC mutations increase the risk of prostate cancer.

Age Factors↗

PubMed2000

Postimplant dosimetry for (125)I prostate implants: definitions and factors affecting outcome.

OBJECTIVE: An analysis of CT-based dosimetry was performed to assess the efficacy of the real time method of prostate implantation, explore the relationship of various dose descriptions and determine implant factors affecting outcome. METHODS AND MATERIALS: Between 7/95 and 8/99, 297 patients underwent (125)I implants for T1-T2 prostate cancer and had CT-based dosimetry performed (TG43 formalism). Dosimetry was performed 1 month postimplant. Using a dose-volume histogram, doses delivered to 100%, 95%, 90%, and 80% of the prostate (D100, D95, D90, D80, respectively) as well as percentages of the gland receiving 240 Gy, 160 Gy, 140 Gy (V240, V160, V140, respectively) were reported. Correlations between the various dose parameters and D90 were generated. The effect of the number of seeds implanted, seeds/volume, prostate volume, experience as assessed by time (8/01/99-date of implant), ultrasound probe (mechanical sector vs. dual phased electronic), and the ratio of the CT dosimetry prostate volume/ultrasound implant volume (CT/US vol) were analyzed. RESULTS: The median D100, D95, D90, and D80 values were 10,200 cGy, 15,655 cGy, 17,578 cGy, and 19,873 cGy, respectively. The median V240, V160, and V140 were 56%, 94%, and 98%, respectively. Correlations of dose descriptions found a close relationship of D95, D80, V240, V160, and V140 with D90 with r values of 0.928, 0.973, 0.911, 0.816, and 0.733, respectively. D100 correlated poorly with D90 (r = 0.099). Using a stepwise regression analysis, CT/US vol ratio, prostate volume, and seed number were the only significant factors affecting D90 with CT/US vol ratio having the greatest effect. The dual-phased electronic probe was associated with fewer D90 values of less than 140 Gy (2%) compared to the mechanical sector probe (14%) (p = 0.02). CONCLUSION: CT-based dosimetry results reveal the real-time implant technique to be an effective method of prostate implantation. Factors associated with more precise implantation, such as decreased postimplant edema, new technology, and increased number of seeds will lead to higher D90 values.

Brachytherapy↗

PubMed2000

Prostate brachytherapy in patients with prostate volumes >/= 50 cm(3): dosimetic analysis of implant quality.

OBJECTIVES: Permanent implantation with (125)I in patients with localized prostate cancer who have prostate volumes >/= 50 cm(3) is often technically difficult owing to pubic arch interference. The objective of this study was to describe dosimetry outcomes in a group of patients who were implanted using the real-time ultrasound-guided technique who had prostate volumes >/= 50 cm(3). MATERIALS AND METHODS: A total of 331 patients received an (125)I prostate seed implant from January 1, 1995, to June 1, 1999, of whom 66 (20%) had prostate volumes >/= 50 cm(3) at the time of the procedure. The real-time seed implant method was used in all patients and consisted of intraoperative planning and real-time seed placement using a combination of axial and sagittal ultrasound imaging. Pubic arch interference was managed using an extended lithotomy position or by angling the tip of the ultrasound probe in an anterior direction. No preimplant pubic arch CT scan study was performed and no patients were excluded from treatment because of prostate size. Implant quality was assessed using CT-based dosimetry performed 1 month postimplant. Dose-volume histograms for the prostate, bladder, rectum, and urethra volumes were generated. The target dose for these implants was 160 Gy and an adequate implant was defined as the dose delivered to 90% of the prostate (D90) >/= 140 Gy. The dose delivered to 95% of the prostate (D95) and doses to 30% of the rectal (DRECT30) and urethral (DURE30) volumes were also calculated. RESULTS: Prostate volumes in the 66 patients ranged from 50 to 93 cm(3) (median 57, mean 61 cm(3)). Total activity implanted was 27.8-89.1 mCi (median 57 mCi), with a range in activity per seed of 0.36-0.56 mCi (median 0.4 mCi). The prostate D90s and D95s ranged from 13,245 to 22,637 cGy (median 18,750) and 11,856 to 20,853 cGy (median 16,725), respectively. Only one patient (1.5%) had a D90 < 140 Gy. The DURE30 values ranged from 15,014 to 27,800 cGy (median 20,410) and the DRECT30 values were 3137-9910 cGy (median 5515). CONCLUSION: Implantation of the large prostate can be accomplished using the real-time method. A total of 98.5% of the patients receive a high-quality implant. In addition, these implants should not put patients at increased risk for significant urinary and bowel complications because urethral and rectal doses can be kept at acceptable levels.

Brachytherapy↗

PubMed2000

Biopsy results after real-time ultrasound-guided transperineal implants for stage T1-T2 prostate cancer.

PURPOSE: To analyze the results of ultrasound-guided brachytherapy for stage T1-T2 prostate cancer, as shown by biopsy results. PATIENTS AND METHODS: The 268 patients (mean age 66 years; range 41-83 years) underwent real-time ultrasound-guided implantation of either iodine-125 (N = 186) or palladium-103 (N = 82) seeds. Of these patients, 96 (36%) received total androgen suppression for 3 months prior to and 3 months after implantation. Prostate biopsy was performed 24 months later, with the six to eight cores all being interpreted by the same pathologist. Each specimen was rated either positive or negative for cancer. RESULTS: Of the 268 patients, 238 (89%) had a negative biopsy at 24 months. Among the patients receiving androgen suppression, 2% were found to have positive biopsies compared with 16% of those not given hormones (P = 0.004). Of the 155 patients with stage T1-T(2a) cancer, 6% had a positive biopsy compared with 19% of patients with stage T(2b) or T(2c) cancer (P = 0.001). In the entire series, the pretreatment serum concentration of prostate specific antigen, Gleason score, and isotope (I v Pd) were not significant predictors of a positive biopsy. However, among the 172 patients who did not receive androgen suppression, all three factors were predictive: 42% for Gleason score of 7 to 10 v 13% for Gleason score < or =6 (P = 0.001): 25% for pretreatment PSA concentration >10 ng/mL v 13% for PSA < or = 10 ng/mL (P = 0.05); and 27% for stage T(2b) or T(2c) v 9% for stage T1 or T(2a) (P = 0.001). The isotope used and the last PSA value were not significant predictors. CONCLUSION: Brachytherapy provides excellent local control of prostate cancer, with 89% of patients having negative biopsies 2 years after treatment. High-risk patients may benefit from the addition of androgen suppression.

Adult↗

PubMed2000

Intraoperative dosimetric representation of the real-time ultrasound-guided prostate implant.

PURPOSE: To describe a method of creating an intraoperative dosimetric representation of the real-time ultrasound-guided prostate implant. MATERIALS AND METHODS: An intraoperative dosimetry system (Multi Media Systems [MMS]) captures transverse ultrasound images after peripheral needles have been implanted in the prostate. The prostate contour and needle positions are outlined on the system. The volume of the prostate with needles in place is calculated. As seeds are deposited in the actual implant, the positions of the seeds are marked on the intraoperative system. Following implantation of the peripheral needles, the resulting isodose lines are displayed. The interior needles are inserted into the prostate, and these positions are captured on the system. As seeds are deposited through these needles into the prostate, their positions are captured on the planning system. When the implant is complete, the final dose coverage and dose volume histogram can be visualized. RESULTS: Ten consecutive patients underwent iodine 125 implants using real-time intraoperative isodose generation. The ratio of the preneedle prostate volume to postneedle prostate volume ranged from 0.89 to 1.0 (median 0.97). The calculated dose delivered to 90% of the prostate volume from the dose volume histogram (D90) ranged from 146.5 to 194 Gy (median 174.75 Gy). The percentage of the prostate covered by 240 Gy ranged from 14.6% to 59% (median 40.75%). CONCLUSION: Dosimetric representation of the real-time ultrasound-guided prostate implant can be achieved and demonstrates the efficacy of this brachytherapy technique.

Brachytherapy↗

PubMed2000

Dynamic cystography can replace cystoscopy following prostate seed implantation.

PURPOSE: To determine if dynamic cystography can replace cystoscopy following prostate seed implantation. MATERIALS AND METHODS: Three hundred three consecutive patients underwent prostate seed implantation using the real-time method. Following implantation, 60 cc of contrast media was injected into the bladder using continuous fluoroscopy. If any seed motion was detected, cystoscopy was performed and any seeds encountered were removed. Patients were followed after discharge for any seeds passed in the urine. RESULTS: Of the 303 patients, 3 (1%) were found to have one or more seeds in the bladder. No patients passed seeds following discharge. There were no adverse events associated with the cystography. CONCLUSION: Dynamic cystography can replace cystoscopy as the postimplant study to evaluated misplaced intravesical or urethral seeds.

Brachytherapy↗

PubMed2000

Prior transurethral resection does not increase morbidity following real-time ultrasound-guided prostate seed implantation.

PURPOSE: Patients with localized prostate cancer who had a prior open prostatectomy or transurethral resection of the prostate (TURP) for benign prostatic hyperplasia (BPH) may be at risk for greater morbidity when treated with brachytherapy. This analysis examines the morbidity following brachytherapy using the real-time method to determine if patients with a history of TURP are at increase risk for developing complications. MATERIALS AND METHODS: An ultrasound-guided transperineal interactive prostate seed was implanted in 419 patients with T1-T2 prostate cancer. All patients were implanted using a peripheral weighting of sources (75%) with the interior sources placed at least 5 mm from the urethra. The patients were divided into two groups: group 1 consisted of 376 patients (89.7%) without a prior TURP, and group 2 consisted of 43 patients (10.3%) who had a TURP prior to their implant. The mean age, prostate-specific antigen level, Gleason score, clinical stage, prostate volume, isotope implanted, and number of patients treated with neoadjuvant hormone therapy were comparable for both groups. RESULTS: Median follow-up for group 1 was 12 months and for group 2 was 18 months. No patients suffered from radiation-related proctitis or cystitis in either group of patients. Two patients in group 2 implanted with iodine 125 and who had a history of two prior TURPs developed mild superficial urethral necrosis (SUN). The actuarial freedom from developing superficial urethral necrosis at 4 years was 84% in patients with a history of prior TURP. There were no episodes of SUN in group 1 and no cases of incontinence reported in either group of patients. The actuarial rate of potency was 78% at 2 years. CONCLUSION: Whereas other techniques of seed implantation report incontinence in patients who had a prior open prostatectomy or TURP, the real-time method combined with peripheral loading avoids this complication.

Adult↗

PubMed2000

Use of radioimmunoscintigraphy with indium-111-labeled CYT-356 (ProstaScint) scan for evaluation of patients for salvage brachytherapy.

PURPOSE: Indium 111 capromab pendetide radioimmunoscintigraphy (ProstaScint) has been used to detect occult recurrent carcinoma after radical prostatectomy. MATERIALS AND METHODS: We evaluated the role of ProstaScint in 24 men with rising prostate-specific antigen (PSA) level following definitive radiation therapy to differentiate between local and distant recurrence in this patient population. RESULTS: ProstaScint scan detected prostatic uptake only in 16 patients, extraprostatic uptake in 5, both prostatic and extraprostatic uptake in 1, and no uptake in 2. Ten of 21 patients with prostatic uptake had positive biopsies, 5 had negative biopsies, and 6 were not biopsied. Two of the three patients with negative scans had positive biopsies, and the third patient was not biopsied. Three patients had evidence of osseous metastasis on radionuclide bone scan, two corresponding to the sites detected on ProstaScint. All three patients had abnormal uptake beyond the prostatic fossa with (n =2) or without (n = 1) prostatic uptake. There were no positive bone scans in patients without extraprostatic uptake on ProstaScint. CONCLUSIONS: ProstaScint scan is useful in detecting occult recurrence outside the prostate in patients with rising PSA following radiation therapy. Compared to data from radical prostatectomy, ProstaScint scans in these patients reveal a higher prevalence of abnormal uptake in the prostate and less frequent extraprostatic uptake.

Aged↗

PubMed2000

Effects of neoadjuvant hormonal therapy on prostate biopsy results after (125)I and (103)Pd seed implantation.

BACKGROUND: Androgen ablation may improve the efficacy of radiation therapy. PATIENTS AND METHODS: A total of 296 patients who had either (125)I (206; 70%) or (103)Pd (90; 30%) transperineal prostate brachytherapy (no external-beam radiation) had routine transrectal ultrasound-guided needle biopsy (minimum six cores) 2 years after treatment without regard to disease status. Neoadjuvant hormonal therapy (NHT: leuprolide acetate and flutamide) was used in 115 patients (39%) for 3 months prior to and 3 months after the implant. RESULTS: Of the 296 patients, 30 (10%) had positive prostate biopsies. Biopsies were positive in 4 of 115 (3.5%) v 26 of 181 (14%) of those who received or had not received NHT, respectively (P = 0.002). When patients were separated into low risk (PSA < or = 10 ng/mL, stage < or = T(2a), and Gleason score < or = 6) and high risk (all others), it was seen that low-risk patients did not benefit from NHT (3.8 v 7.7% positive biopsy rate; P = 0.5) whereas high-risk patients did (3.4% v 21.1%; P = 0.003). CONCLUSION: Prostate brachytherapy yields high negative biopsy rates (90%) 2 years after treatment. Neoadjuvant hormonal therapy can improve the local control rates (as determined by biopsy) in patients undergoing (125)I or (103)Pd seed implantation. These results are most significant for patients who present with PSA >10 ng/mL, stage > or = T(2b) diseases, or Gleason score > or = 7 (high-risk status).

Androgen Antagonists↗

PubMed1999

Does prostate brachytherapy treat the seminal vesicles? A dose-volume histogram analysis of seminal vesicles in patients undergoing combined PD-103 prostate implantation and external beam irradiation.

PURPOSE: Combined brachytherapy of the prostate and external beam irradiation (EBRT) of the prostate and seminal vesicles (SV) is becoming a popular treatment for high-risk prostate cancer. Dose-volume histogram (DVH) analysis of the SV in patients undergoing this treatment was performed to determine the dose distribution to the SV and the adequacy of this treatment in patients with potential SV involvement. METHODS AND MATERIALS: Twenty-five consecutive patients were treated with a Pd-103 implant of the prostate alone and 45 Gy of EBRT to the prostate and SV. Attempts were not made to implant the SV but seeds were routinely placed at the junction of the prostate and SV. All patients underwent CT-based postimplant dosimetric analysis 1 month after implantation. As part of this analysis, DVH were generated for the prostate and total SV volume (SVT). In addition, the SV was divided into 6-mm-thick volumes identified as SV1, SV2, SV3, SV4, and SV5 starting from the junction of the prostate and SV and extending distally. DVH were also generated for these structures. Delivered dose was defined as the D90 (dose delivered to 90% of the organ on DVH). RESULTS: The median volumes in cc of the prostate, SVT, SV1, SV2, SV3, SV4, and SV5 were 34.33, 9.75, 2.7, 3.48, 2.92, 3.18, and 1.96 respectively. The SVT contained from 0-9 seeds (median 2). There was little dose delivered to the SVT and SV volumes from the implanted prostate. The median D90 values for the prostate, SVT, SV1, SV2, SV3, SV4, and SV5 were 8615 cGy, 675 cGy, 3100 cGy, 1329 cGy, 553 cGy, 246 cGy, and 67 cGy, respectively. The dose delivered to the prostate covered small percentages of SV. The percents of SV volumes covered by the prostate D90 were 11, 35, 3.3, 0, 0, and 0 for SVT, SV1, SV2, SV3, SV4, and SV5, respectively. CONCLUSIONS: DVH analysis of the SV reveals that dose generated from an implanted prostate contributes little to the SV. Those patients at high risk for SV involvement may be undertreated with combined EBRT to prophylactic doses and prostate implantation.

Brachytherapy↗

PubMed1999

Rectal cancer and inflammatory bowel disease: natural history and implications for radiation therapy.

PURPOSE: There exists little information concerning the natural history of rectal cancer in patients with inflammatory bowel disease (IBD). In addition, the tolerance of pelvic irradiation in these patients is unknown. We analyzed the largest series of patients with IBD and rectal cancer in order to determine the natural history of the disease as well as the effect and tolerance of pelvic irradiation. METHODS AND MATERIALS: A retrospective analysis of 47 patients with IBD and rectal cancer treated over a 34-year period (1960-1994) was performed. Thirty-five patients had ulcerative colitis and 12 patients had Crohn's disease. There were 31 male patients and 16 female patients. The stage (AJC) distribution was as follows: stage 0 in 5 patients, stage I in 13 patients, stage II in 7 patients, stage III in 13 patients, and stage IV in 9 patients. Surgical resection was performed in 44 patients. In two of these patients, preoperative pelvic irradiation was given followed by surgery. Twenty of these patients underwent postoperative adjuvant therapy (12 were treated with chemotherapy and pelvic irradiation and 8 with chemotherapy alone). Three patients were found to have unresectable disease and were treated with chemotherapy alone (2 patients) or chemotherapy and radiation therapy (RT) (1 patient). Radiation complications were graded using the RTOG acute and late effects scoring criteria. Follow-up ranged from 4 to 250 months (median 24 months). RESULTS: The 5-year actuarial results revealed an overall survival (OS) of 42%, a disease-free survival (DFS) of 43%, a pelvic control rate (PC) of 67% and a freedom from distant failure (FFDF) of 47%. DFS decreased with increasing T stage with a 5-year rate of 86% for patients with Tis-T2 disease compared to 10% for patients with T3-T4 disease (p < 0.0001). The presence of lymph node metastases also resulted in a decrease in DFS with a 5-year rate of 67% for patients with NO disease compared to 0% for patients with N1-N3 disease (p < 0.0001). DFS decreased with increasing histopathologic grade with 5-year DFS rates of 71%, 52%, and 24% for grades 1, 2, and 3 respectively (p = 0.03). The T and N stages showed a statistically significant effect on pelvic control, with 5-year PC rates of 60% for Tis-2 versus 26% for T3-4 (p = 0.002) and 79% for NO versus 51% for N1-3 (p = 0.007). The histopathologic grade of the tumor did not significantly affect pelvic control. An analysis of high-risk patients (30) with T3-T4 or N1-N3 disease revealed at 5 years an OS of 9%, a DFS of 10%, a PC rate of 26%, and FFDF of 20%. In this subset of patients, there was a trend toward improved pelvic control in patients receiving RT (14 patients) with a 5-year PC of 60% compared to a rate of 23% for those patients not irradiated (16 patients). Acute complications (grade 3 or >) were noted in three patients (20%) receiving pelvic irradiation +/- chemotherapy and these included two cases of grade 3 skin reactions and one case of grade 4 gastrointestinal toxicity. Two patients (13%) developed small bowel obstruction at 2 and 4 months, respectively, postirradiation which were managed conservatively. There were no long-term complications in patients irradiated. CONCLUSION: Treatment results are comparable to those historically reported for non-IBD-related rectal cancer although the subset of high-risk patients appeared to have a poorer outcome. In light of this finding and the ability of these patients to tolerate chemotherapy and pelvic irradiation, aggressive adjuvant therapy should be given to IBD-associated rectal cancer patients with high-risk features.

Adolescent↗

PubMed1999

PSA kinetics following I-125 radioactive seed implantation in the treatment of T1-T2 prostate cancer.

Although there is renewed interest in prostate brachytherapy, little information is available on the effect of the procedure on prostate-specific antigen (PSA) changes over time. This study describes PSA kinetics after iodine-125 (I-125) transrectal ultrasound-guided transperineal implantation of the prostate. From February 1991-September 1997, 207 patients were treated with an I-125 prostate implant alone for T1-T2 prostate cancer. PSA values were obtained prior to treatment and at 1-73 months (median, 24 months). The change in PSA after implantation of the prostate was measured as a fraction of the pretreatment PSA (PSA at follow-up/pretreatment PSA). PSA failure was defined as two elevations in PSA or PSA > 1 ng/ml. One hundred fifty-five patients had PSA values recorded at the 1-month time period. A PSA value greater than the pretreatment PSA at 1 month was found in 27% (42/155). This had no significant effect on future PSA failure. The median percentage change in PSA after implantation for all patients were as follows: 1 month, 0.73; 3 months, 0.30; 6 months, 0.18; 12 months, 0.12; 18 months, 0.12; 24 months, 0.08; 30 months, 0.07; 36 months, 0.08; 42 months, 0.08; and 48 months, 0.05. The most significant decline occurred in the first 12 months. This was followed by a more gradual decline between 12-24 months. There was little change in PSA values after 24 months. The 1-year PSA value had a significant effect on PSA failure. Patients with a 1-year PSA <1 ng/ml (66) had an actuarial 4-year freedom-from-failure rate of 90%, compared to a rate of 62% for those with values >1 ng/ml (69) (P = 0.002). Twenty-seven patients developed PSA failure. The time to PSA failure ranged from 12-48 months (median, 24 months), but most (20/27) failures occurred after 18 months. We conclude that the greatest decline in PSA after I-125 implantation of the prostate occurs during the first year, and little change occurs after 2 years. A 1-year PSA value > 1 ng/ml is highly predictive of eventual PSA failure, which occurs in most patients after 18 months posttreatment.

Adenoma↗

PubMed1999

Prostate brachytherapy: treatment strategies.

PURPOSE: Patients who present with localized and locally advanced prostate cancer may be candidates for prostate brachytherapy. We evaluated the treatment outcomes in a diverse group of prostate cancer patients who presented with low, moderate and high risk features. MATERIALS AND METHODS: A total of 301 patients who presented with T1 to T3 prostate cancer were treated with brachytherapy alone or combined with hormonal therapy and/or external beam irradiation. Of these patients 109 at low risk with prostate specific antigen (PSA) 10 ng./ml. or less, Gleason score 6 or less and clinical stage T2a or less were treated with 125iodine alone, 152 at moderate risk with PSA greater than 10 ng./ml., Gleason score greater than 6 or stage T2b or greater were treated with 125iodine or 103palladium or combined implant alone with 5 months of hormonal therapy, and 40 at high risk with PSA greater than 15 ng./ml., Gleason 8 or greater, clinical stage T2c to T3 or positive seminal vesicle biopsy (20) were treated with combination brachytherapy, external beam irradiation and 9 months of hormonal therapy. Patients with a positive seminal vesicle biopsy (T3c disease) and negative pelvic lymph nodes were included in the high risk group, and the walls of the seminal vesicles were also treated with implantation. Followup was performed every 6 months with digital rectal examination and ultrasound evaluation. Prostate biopsy was routinely recommended 2 years after completion of the radiation. Failure was defined as PSA increase on 2 consecutive determinations above 1 ng./ml. or evidence of local recurrence on digital rectal examination, transrectal ultrasound or biopsy. Kaplan-Meier projections were used to calculate progression-free survival rates. RESULTS: Of the 109 patients at low risk followed from 1 to 7 years (median 18 months) 91% were free of PSA failure at 4 years. No patient experienced urinary incontinence following implantation, although grade 1 to 2 radiation proctitis occurred in 5 (4.5%). Of the 152 patients at moderate risk 73 received implantation and 79 received implantation combined with hormonal therapy. The 4-year biochemical freedom from failure rate for the hormone group was 85% versus 58% for the no hormone group (p = 0.08). The difference was more significant for those with Gleason score 7 or greater (90 versus 43%, p = 0.01) and for those with PSA greater than 10 ng./ml. (87 versus 59%, p = 0.04). Grade 1 to 2 radiation proctitis occurred in 1 of the 79 patients (1.3%) receiving hormonal therapy and in 3 (4%) treated with implantation only. There were no cases of urinary incontinence. Of the 40 patients at high risk 71% were free of biochemical failure at 3 years. Of the 4 patients with failure (10%) 3 (75%) originally had positive seminal vesicle biopsies. Five patients experienced gastrointestinal complications, although none was grade 3 or 4. The actuarial freedom from grade 2 proctitis was 82%. No patient experienced urinary incontinence. Prostate biopsies were negative in 87% of the low risk, 96.8 (hormone group) versus 68.6% (no hormone group) of the moderate risk (p = 0.0023) and 86% of the high risk patients. CONCLUSIONS: Brachytherapy appears to offer comparable results to external beam irradiation and radical prostatectomy when patients are stratified by disease extent. Adopting a strategy of implant alone, implant with hormonal therapy or implant with hormonal therapy and external beam irradiation in patients who present with low to high risk features can improve the overall results in the more advanced cases.

Brachytherapy↗