PubMed Health⌕ Search

Biomedical subjects

Kent E Wallner

Publications and source records attributed to Kent E Wallner.

12 recordsLinked to original sources
PubMed2003

Late rectal function after prostate brachytherapy.

PURPOSE: Using a patient-administered quality of life instrument, to evaluate the effect of permanent prostate brachytherapy on late rectal function. METHODS AND MATERIALS: One hundred eighty-nine prostate brachytherapy patients were mailed the Rectal Function Assessment Score (R-FAS), with a prestamped return envelope. The R-FAS consists of nine questions and a scoring range of 0-27, with higher scores indicative of poorer bowel function. One hundred eighty-seven (98.4%) surveys were returned. The median follow-up was 66.3 months (range 54-92 months). Clinical, treatment, and dosimetric parameters evaluated for bowel dysfunction included patient age, diabetes, hypertension, tobacco consumption, clinical T-stage, elapsed time since implant, prostate ultrasound volume, planning target volume, hormonal status, supplemental external beam radiation therapy (EBRT), isotope, average, median and maximum rectal doses, total implanted seed strength, values of the minimum dose received by 90% of the prostate gland (D(90)), and the percent prostate volume receiving 100%, 150%, and 200% of the minimum prescribed dose (V(100/150/200)). RESULTS: The R-FAS score for the evaluated cohort was 3.92, which represented a slight improvement from the 1999 survey score of 4.15 (p = 0.29). Of the evaluated clinical, treatment, and dosimetric parameters, the number of preimplant bowel movements, a history of tobacco consumption, and the median rectal dose correlated with the R-FAS. Although lower rectal doses were noted with Pd-103, isotope did not predict for bowel function. Only 12% (23/187) of patients reported their bowel function to be worse after implantation. Patient perception of overall rectal quality of life was inversely related to the use of supplemental EBRT (p = 0.007). CONCLUSION: Minor bowel changes are noted following prostate brachytherapy. The vast majority of patients did not report any deterioration in bowel function. In addition, the R-FAS continue to improve with time.

Aged↗
PubMed2003

Isodose patterns in patients with inadequate prostate brachytherapy coverage.

PURPOSE: The development of a practical, real-time dosimetry system should result in improved implant dose distributions and higher prostate cancer control rates. Our purpose here is to demonstrate that intraoperative isodose reconstruction in relation to the seed distribution, even without accurate registration with the prostatic volume, can likely identify an inadequate implant intraoperatively and guide corrective seed placement. METHODS AND MATERIALS: A total of 102 Pd-103 implants performed by standard techniques, using a modified peripheral loading pattern, were studied. A postimplant computed tomography (CT) scan was obtained 2-4 h after the implant. The contoured images and sources were entered into a Varian Variseed 7.0 treatment planning system. Dosimetric parameters analyzed included the percent of the postimplant prostate or rectal volume covered by the prescription dose (V100), and the dose that covers 90% of the postimplant prostate volume (D90). Isodose patterns were analyzed at midprostate, and for the entire prostate. Adverse isodose patterns were defined as gaps, holes, islands. Isodose gaps are subprescription intervals between the prostatic margin and the prescription isodose. Isodose holes are regions of subprescription dose within the prostate. Isodose islands are isolated regions > or =prescription dose inside the prostatic margins. RESULTS: Characteristic isodose patterns were predictive for V100 values. Midprostatic isodose holes were seen in 55% of patients with a V100 < 80%, 5% of patients with a V100 of 80-90%, and only 1% of patients with a V100 > 90%. When analyzing the entire prostate, isodose holes were seen in 55% of patients with a V100 < 80%, 18% of patients with a V100 of 80-90%, and 9% of patients with a V100 > 90%. Midprostatic isodose islands were seen in 55% of patients with a V100 < 80%, 5% of patients with a V100 of 80-90%, and no patient with a V100 > 90%. When analyzing the entire prostate, isodose islands were seen in all patients with V100 < 80%, 36% of patients with a V100 of 80-90%, and only 1% of patients with a V100 > 90%. The likelihood of a V100 less than 80% was best predicted by the presence of isodose holes or islands at midprostate. Patients with either finding had an 86% chance of having a V100 < 80%. CONCLUSIONS: These semiquantitative findings can provide practical guidelines for intraoperative dosimetry, to provide a more rational guide to intraoperative postimplant assessment and modification. If isodose holes or islands are seen within the implanted volume, additional seeds are added to the affected region to obtain a V100 > 80%.

Brachytherapy↗
PubMed2003

Long-term urinary quality of life after permanent prostate brachytherapy.

PURPOSE: To evaluate late urinary function after permanent prostate brachytherapy using a validated, patient-administered quality-of-life instrument. METHODS AND MATERIALS: A total of 225 consecutive patients underwent prostate brachytherapy between April 1995 and March 1998. Of the 225 patients, 17 had died and 3 had been institutionalized secondary to Alzheimer's disease. Of the remaining 205 patients, each was mailed a self-administered questionnaire (the urinary function component of the Expanded Prostate Cancer Index [EPIC] and the International Prostate Symptom Score [IPSS]). Of the 205 surveys mailed, 195 (95.1%) were returned. The mean and median follow-up was 66.3 and 64.0 months, respectively. The clinical parameters evaluated included age, pretreatment prostate-specific antigen level, Gleason score, stage, risk group, prostate volume, presence of diabetes and hypertension, and tobacco consumption. The treatment parameters included the ultrasound planning volume, hormonal status, use of supplemental external beam radiotherapy, isotope, and follow-up. The dosimetric parameters included values of the minimal dose received by 90% of the prostate gland and the percentage of prostate volume receiving 100%, 150%, and 200% of the prescribed minimal peripheral dose. Because detailed baseline urinary function was not available, a cross-sectional survey was performed in which 51 newly diagnosed prostate cancer patients of comparable demographics served as controls. RESULTS: When the survey scores for the implant patients were compared with the control group, no significant differences in either the IPSS or function, bother, incontinence, or irritation/obstruction subscales of the urinary EPIC were discernible. In addition, no significant difference was observed between the implant and control groups when the EPIC and IPSS surveys were evaluated by each individual question. Of all the evaluated parameters, the use of tobacco was the best predictive variable for diminished quality of life. CONCLUSION: No significant difference was noted in the overall long-term urinary quality of life when brachytherapy patients were compared with a group of newly diagnosed prostate cancer patients of comparable demographics. Of all parameters evaluated, tobacco consumption was the single strongest predictor of late urinary function.

Aged↗
PubMed2003

Dysuria after permanent prostate brachytherapy.

PURPOSE: Although numerous prostate cancer quality-of-life studies have been reported, a paucity of data exists regarding brachytherapy-related dysuria. In this study, we evaluated the incidence and temporal resolution of dysuria, along with the influence of multiple treatment, clinical, and dosimetric parameters. MATERIALS AND METHODS: Five hundred eighty-one consecutive patients without a preimplant history of transurethral resection of the prostate underwent brachytherapy between January 1998 and December 2001 for clinical T1c-T3a (1997 AJCC) adenocarcinoma of the prostate gland. The evaluated population consisted of the 546 patients who had completed at least two postimplant dysuria evaluations. The median patient follow-up was 26.4 months. In all patients, alpha-blocker therapy was initiated before implantation and continued at least until the International Prostate Symptom Score (IPSS) returned to baseline. The frequency of dysuria was assessed on a 1-5 scale using the IPSS scoring criteria. The dysuria severity was scored on a 1-10 scale. The clinical parameters evaluated included age, T stage, preimplant IPSS, ultrasound volume, and elapsed time since implantation. The treatment parameters included the use of neoadjuvant hormonal manipulation, use of supplemental external beam radiotherapy, isotope, and total implanted seed strength. The dosimetric parameters included values of the minimal dose received by 90% of the prostate, the percentage of prostate volume receiving 100%, 150%, and 200% of the prescribed minimal peripheral dose, and the median and maximal urethral doses. RESULTS: The incidence of dysuria peaked at 52% 1 month after implantation. The median dysuria frequency score was 0 of 5 for all patients and 2 of 5 for those reporting dysuria. The median severity score was 0 of 10 for the entire cohort and 3 of 10 for those reporting dysuria. For the entire group, both the frequency and the severity of dysuria steadily improved with time, with near complete resolution of dysuria at 45 months. For those patients reporting dysuria, neither the frequency nor the severity revealed any durable improvement for approximately 36 months. Patients with dysuria displayed higher postimplant IPSSs. Of the 7 IPSS questions, nocturia and incomplete voiding were the best surrogates for dysuria. The isotope, supplemental external beam radiotherapy, hormonal status, minimal dose received by 90% of the prostate, and urethral dose did not predict for dysuria. CONCLUSIONS: After permanent prostate brachytherapy, dysuria is a relatively common event, but only rarely severe in frequency or intensity. At approximately 45 months after brachytherapy, dysuria appears to resolve in almost all patients.

Aged↗
PubMed2003

Permanent interstitial brachytherapy for the management of carcinoma of the prostate gland.

PURPOSE: We summarize the permanent prostate brachytherapy literature, including biochemical outcomes, quality of life parameters and areas of controversy. MATERIALS AND METHODS: The permanent prostate brachytherapy literature was reviewed using MEDLINE searches to ensure completeness. RESULTS: Using various planning and intraoperative techniques the majority of the brachytherapy literature demonstrates durable biochemical outcomes for patients with low, intermediate and high risk features. For low risk patients there is no advantage to combining supplemental external beam radiation therapy with brachytherapy. In addition, supplemental external beam radiation therapy may not improve biochemical outcomes for patients at intermediate and high risk if the target volume consists of the prostate with a generous periprostatic margin. There is no defined role for adjuvant hormonal manipulation. Although a reliable set of pretreatment criteria to predict implant related morbidity is not available, severe urinary and rectal morbidity is rare. The incidence of brachytherapy induced erectile dysfunction is significantly greater than initially reported but the majority of patients respond favorably to sildenafil. CONCLUSIONS: Continued refinements in brachytherapy planning and implementation techniques, postimplantation evaluation and continued elucidation of the etiology of urinary, bowel and sexual dysfunction should result in further improvements in biochemical and quality of life outcomes.

Brachytherapy↗
PubMed2003

Management of sexual dysfunction after prostate brachytherapy.

Erectile dysfunction is a common sequela following potentially curative local treatment for early-stage carcinoma of the prostate gland. With larger studies and longer follow-up, it is clear that erectile dysfunction following prostate brachytherapy is more common than previously reported, with a myriad of previously unrecognized sexual symptoms. Approximately 50% of patients develop erectile dysfunction within 5 years of implantation. Several factors including preimplant potency, patient age, the use of supplemental external-beam irradiation, radiation dose to the prostate gland, radiation dose to the bulb of the penis, and diabetes mellitus appear to exacerbate brachytherapy-related erectile dysfunction. The majority of patients with brachytherapy-induced erectile dysfunction respond favorably to sildenafil citrate (Viagra). Despite reports questioning the potency-sparing advantage associated with brachytherapy, recent elucidations of brachytherapy-related erectile dysfunction may result in refinement of treatment techniques, an increased likelihood of potency preservation, and ultimately, improved quality of life.

Adult↗
PubMed2002

Ultrasonography and fluoroscopic fusion for prostate brachytherapy dosimetry.

PURPOSE: To investigate the feasibility of performing postimplant and intraoperative dosimetry for prostate brachytherapy by fusing transrectal ultrasound (TRUS) and fluoroscopic data. METHODS AND MATERIALS: Registration of ultrasound (prostate boundary) and fluoroscopic (seed) data requires spatial markers that are detectable by both imaging modalities. In this study, the needle tips were considered as such fiducials. Prostate phantoms were implanted with the seeds, and four localization needles were inserted. In the TRUS frame of reference, the longitudinal coordinate of the needle tip was determined by advancing the needle until the echo from its tip just registered at a known probe depth. The tip's transverse coordinates were determined from the associated TRUS slice. The three-dimensional needle tip positions were also calculated in the fluoroscopic coordinate system using a seed reconstruction method. The transformation between the TRUS and fluoroscopy coordinate systems was established by the least-squares solution using the singular value decomposition. RESULTS: With three of four needle tips as fiducials and the one remaining needle as a test target, the mean fiducial registration error was 0.8 mm and the test target registration error was 2.5 mm. When all four points were used for registration, the errors decreased to 1.1 mm. A comparison between the proposed method and CT-based dosimetry yielded a percentage of prostate volume receiving 100% and 150% of the prescribed minimal peripheral dose and minimal dose received by 90% of the prostate gland that agreed within 0.4%, 2.7%, and 4.2%, respectively. CONCLUSION: The combination of TRUS and fluoroscopy is a feasible alternative to the currently used CT-based postimplant dosimetry. Furthermore, because of online imaging capability, the method lends itself to real-time intraoperative applications.

Brachytherapy↗
PubMed2002

The importance of radiation doses to the penile bulb vs. crura in the development of postbrachytherapy erectile dysfunction.

PURPOSE: Recent studies have implicated the proximal penis as a potential site-specific structure for radiation-related erectile dysfunction (ED). In this study, we evaluated by means of a validated patient-administered questionnaire whether radiation doses to the bulb of the penis and/or the proximal corporeal bodies were predictive for the development of brachytherapy-induced ED. METHODS AND MATERIALS: Thirty patients who underwent permanent prostate brachytherapy between April 1995 and October 1999 and developed brachytherapy-induced ED were paired with 30 similar men who maintained potency after implantation. None of the 60 patients received supplemental external beam radiation therapy, either before or after implantation. Potency was assessed by patient self-administration of the specific erectile questions of the International Index of Erectile Function. The questionnaire consisted of 5 questions with a maximum score of 25. Postimplant potency was defined as an International Index of Erectile Function score > or =11. Mean and median follow-up was 48.3 +/- 14.4 months and 48.0 months, respectively (range: 26.6-79.3 months). The bulb of the penis and the proximal crura were outlined at 0.5-cm intervals on the Day 0 postimplant CT scan. The radiation dose distribution to the bulb of the penis and adjacent crura was defined in terms of the minimum dose delivered to 25%, 50%, 70%, 75%, 90%, and 95% of the bulb (D(25), D(50), D(70), D(75), D(90), and D(95)). RESULTS: The radiation dose delivered to the bulb of the penis and the proximal crura in men with brachytherapy-induced ED was statistically greater for all evaluated dosimetric parameters (D(25), D(50), D(70), D(75), D(90), and D(95)). Stepwise linear regression analysis indicated that penile bulb dose parameter D(50), the postimplant prostate CT volume, and patient age at implant were predictive of postimplant ED, whereas the crura dose D(25) approached statistical significance. Seventy-five percent of the impotent men had a bulb D(25) >60% of prescribed minimum peripheral dose (mPD), whereas 80% of potent men had a bulb D(25) < or =60% mPD. Using the D(50) bulb parameter, 70% of ED men had a dose >40% mPD, whereas 90% of potent men had a dose < or =40% mPD. Similar cut points for D(25) and D(50) crura doses were 40% and 28% mPD. The crura D(25) cut point was exceeded by 50% of the ED patients and only 7% of the potent patients. CONCLUSION: This is the first study to evaluate potency preservation and radiation doses to the proximal penis by means of a validated patient-administered quality-of-life instrument. Our data confirm prior reports that radiation doses to the proximal penis are predictive of brachytherapy-induced ED. In a stepwise linear regression analysis, the strongest predictors of potency preservation were bulb D(50), postimplant prostate CT volume, and patient age. With Day 0 dosimetric evaluation, the penile bulb D(50) and D(25) should be maintained below 40% and 60% mPD, respectively, whereas the crura D(50) and D(25) should be maintained below 40% and 28% mPD, respectively, to maximize posttreatment potency.

Age Factors↗
PubMed2002

Prostate-specific antigen spikes after permanent prostate brachytherapy.

PURPOSE: To evaluate whether any clinical, treatment, or dosimetric parameters correlated with the development of a prostate-specific antigen (PSA) spike after permanent prostate brachytherapy. METHODS AND MATERIALS: The evaluated population consisted of 218 hormone-naive patients free of biochemical or clinical failure who underwent permanent prostate brachytherapy with or without supplemental external beam radiotherapy for clinical Stage T1b-T3a adenocarcinoma of the prostate gland (1997 AJCC) between August 1995 and November 1999. No patient underwent pre- or postimplant hormonal manipulation, pretreatment seminal vesicle biopsy, or pathologic lymph node staging. In addition, none of the 218 patients possessed equivocal biochemical results (one or two consecutive PSA rises or a declining PSA >1.0 ng/mL). The median patient follow-up was 46.2 months. A PSA spike was defined as a rise of >or=0.2 ng/mL, followed by a durable decline. The clinical parameters evaluated included patient age, clinical T stage, Gleason score, pretreatment PSA level, prostate volume, brachytherapy planning volume, and patient follow-up in months. The evaluated treatment parameters included isotope and use of supplemental external beam radiotherapy. The dosimetric parameters evaluated included the minimal dose received by 90% of the prostate gland (D(90)), the percentage of the prostate volume receiving 100% (V(100)), 150%, and 200% (V(200)) of the prescribed minimal peripheral dose, and the mean, median, maximal, and minimal urethral doses. Biochemical disease-free survival was defined by the American Society for Therapeutic Radiology and Oncology consensus definition with the additional constraint that the most recent PSA level was 0.2 to 0.5 to 1.0 ng/mL (20%, 50%, and 80%, respectively, p <0.001). In Cox multivariate regression analysis, patient age, clinical stage, first postimplant PSA level, and V(150) were predictive for the development of a PSA spike. A postimplant dosimetric threshold of either <115% of the minimal peripheral dose for D(90) or <55% of the prostate volume for V(150) was strongly predictive of a spike. When the variables only determinable after the occurrence of the PSA spike were included in the multivariate analysis, V(150), preimplant PSA level, and nadir PSA were the significant predictors. CONCLUSION: Of the patients, 23.9% developed a PSA spike with a median time to development of 16.3 months and a median prespike and median postspike PSA of 0.50 ng/mL and 0.90 ng/mL, respectively. In multivariate analysis, patient age, clinical stage, first postimplant PSA level, and V(150) were predictive for the development of a PSA spike. At approximately 66 months after implantation, the PSA curves converged for spike and nonspike patients, with a median PSA level <0.1 ng/mL.

Adenocarcinoma↗
PubMed2002

Penile bulb imaging.

PURPOSE: Because of the apparent relationship between potency loss and radiation doses to the erectile bodies, there is increasing rationale for incorporating penile bulb dosimetry into treatment planning and posttreatment evaluation. Because the location and shape of the penile bulb have not been described in detail on various imaging modalities, we herein describe the anatomic boundaries of the penile bulb on computed tomography (CT), magnetic resonance imaging (MR), and transrectal ultrasound (TRUS), before and after brachytherapy. METHODS AND MATERIALS: Nonenhanced axial CT images were taken on a CTi CT Scanner (General Electric Medical Systems, Milwaukee, WI) with the patient in the supine position. Settings were at 300 ma, 140 kvp, 4-s scan time per slice, and collimation of 3 mm with data obtained at 3-mm intervals. Nonenhanced MR images were obtained with a 1.5 Tesla Signa Horizon LX Scanner using fast spin-echo T1-weighted (TR/TE, 466/20) and T2-weighted (TR/TE, 8000/90) images, with a slice thickness of 2 mm and an interslice gap of 0.5 mm. TRUS images were obtained with a Siemens SONOLINE Prima ultrasound machine at 6.0 MHz and a Winston-Barzell stepper unit. RESULTS: The penile bulb is best visualized on T2-weighted MR images in the axial, sagittal, and coronal planes, appearing as an oval-shaped, hyperintense midline structure. On axial CT imaging, the bulb of the penis is typically readily identifiable, bounded by the paired crura laterally, the corpora spongiosum anteriorly, and the levator ani posteriorly. The penile bulb is typically well visualized on transverse TRUS, but usually only faintly seen on sagittal TRUS. The bulb is partially obscured on postimplant CT and MR images, presumably because of implant-related edema. Bulb volumes vary markedly from patient to patient, ranging from 5.6 to 12.4 cc (median: 8.1 cc). CONCLUSION: Closer attention to penile erectile tissue doses should lead to improved external beam radiation and brachytherapy delivery. It will benefit the radiation oncology community to become familiar with these imaging findings, so that penile bulb dosimetry can be incorporated into our daily practice.

Humans↗
PubMed2002

Prophylactic versus therapeutic alpha-blockers after permanent prostate brachytherapy.

OBJECTIVES: To evaluate the influence of prophylactic versus therapeutic alpha-blockers on urinary morbidity after permanent prostate brachytherapy. Multiple clinical and treatment parameters were evaluated to identify the factors associated with acute urinary morbidity. METHODS: A total of 234 consecutive patients underwent permanent prostate brachytherapy in one of two prospective randomized studies from October 1999 through February 2001 using either palladium-103 or iodine-125 for clinical Stage T1b-T2b (1997 American Joint Commission on Cancer staging system) prostate cancer at either the Schiffler Cancer Center or Puget Sound Health Care System. The mean and median follow-up was 8.8 +/- 4.6 months and 6 months, respectively. In 142 patients, an alpha-blocker was initiated before implantation and continued at least until the International Prostate Symptom Score (IPSS) returned to baseline levels; 92 patients either did not receive an alpha-blocker or received a therapeutic alpha-blocker after implantation because of urinary obstructive symptoms. The clinical and treatment parameters evaluated for urinary morbidity included prophylactic versus therapeutic alpha-blockers, age, preimplant IPSS, ultrasound volume, use of neoadjuvant hormones, use of supplemental external beam radiotherapy, isotope, urethral dose, and multiple dosimetric quality indicators (minimal dose received by 90% of the prostate gland and percentage of prostate volume receiving 100% or 200% of the prescribed minimal peripheral dose). Catheter dependency and the duration of alpha-blocker dependency were also evaluated. RESULTS: In both the prophylactic and the therapeutic cohorts, the IPSS peaked 1 month after implantation. Patients receiving a prophylactic alpha-blocker returned to baseline at a mean of 4 months and a median of 3 months postoperatively. For those patients not receiving prophylactic alpha-blockers, the IPSS returned to the antecedent value at a mean and median of 10 months and 6 months, respectively. Of the 125 patients receiving prophylactic alpha-blockers, 102 (81.2%) remained medication dependent at the conclusion of the study, and 140 (78.2%) of 179 patients receiving alpha-blockers other than for hypertensive purposes did so. The incidence of prolonged urinary catheter dependency (greater than 3 days) and the need for postimplant transuretheral incision of the prostate/transurethral resection of the prostate were not affected by alpha-blocker use. Cox regression analysis revealed that only the prophylactic use of alpha-blockers and the difference between the preimplant IPSS and the 1-month IPSS were predictive of the time to return to the referent zone. CONCLUSIONS: Prophylactic use of alpha-blockers results in significantly less urinary morbidity than either the absence or therapeutic use of alpha-blockers. In patients receiving prophylactic alpha-blockers, the IPSS normalized significantly faster but had no impact on urinary retention or the ultimate need for postimplant surgical intervention.

Adenocarcinoma↗