Biomedical subjects

Steven A Leibel

Publications and source records attributed to Steven A Leibel.

At least 19 recordsLinked to original sources

PubMed2006

Intensity-modulated radiotherapy in high-grade gliomas: clinical and dosimetric results.

PURPOSE: To report preliminary clinical and dosimetric data from intensity-modulated radiotherapy (IMRT) for malignant gliomas. METHODS AND MATERIALS: Fifty-eight consecutive high-grade gliomas were treated between January 2001 and December 2003 with dynamic multileaf collimator IMRT, planned with the inverse approach. A dose of 59.4-60 Gy at 1.8-2.0 Gy per fraction was delivered. A total of three to five noncoplanar beams were used to cover at least 95% of the target volume with the prescription isodose line. Glioblastoma accounted for 70% of the cases, and anaplastic oligodendroglioma histology (pure or mixed) was seen in 15% of the cases. Surgery consisted of biopsy only in 26% of the patients, and 80% received adjuvant chemotherapy. RESULTS: With a median follow-up of 24 months, 85% of the patients have relapsed. The median progression-free survival time for anaplastic astrocytoma and glioblastoma histology was 5.6 and 2.5 months, respectively. The overall survival time for anaplastic glioma and glioblastoma was 36 and 9 months, respectively. Ninety-six percent of the recurrences were local. No Grade IV/V late neurologic toxicities were noted. A comparative dosimetric analysis revealed that regardless of tumor location, IMRT did not significantly improve target coverage compared with three-dimensional planning. However, IMRT resulted in a decreased maximum dose to the spinal cord, optic nerves, and eye by 16%, 7%, and 15%, respectively, owing to its improved dose conformality. The mean brainstem dose also decreased by 7%. Intensity-modulated radiotherapy delivered with a limited number of beams did not result in an increased dose to the normal brain. CONCLUSIONS: It is unlikely that IMRT will improve local control in high-grade gliomas without further dose escalation compared with conventional radiotherapy. However, it might result in decreased late toxicities associated with radiotherapy.

Adult↗

PubMed2005

Whole pelvic radiotherapy for prostate cancer using 3D conformal and intensity-modulated radiotherapy.

PURPOSE: To investigate the correlations between observed clinical morbidity and dosimetric parameters for whole pelvic radiotherapy (WPRT) for prostate cancer using either three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT). METHODS AND MATERIALS: Between December 1996 and January 2002, 27 patients with prostate adenocarcinoma were treated with conformal WPRT as part of their definitive treatment. WPRT was delivered with 3D-CRT in 14 patients and with IMRT in 13 patients. For each of the patients treated with IMRT, optimized conventional two-dimensional (2D) and 3D-CRT plans were retrospectively generated for the whole pelvic phase of the treatment. Dose-volume histograms for the bowel, bladder, and rectum were compared for the three techniques. Acute toxicities were evaluated for all 27 patients, and late toxicities were evaluated for 25 patients with sufficient follow-up. Toxicities were scored according to the Radiation Therapy Oncology Group morbidity grading scales. Median follow-up was 30 months. RESULTS: Three-dimensional-CRT resulted in a 40% relative reduction (p < 0.001) in the volume of bowel receiving 45 Gy compared with 2D, and IMRT provided a further 60% reduction relative to 3D-CRT (p < 0.001). Compared with either 2D or 3D-CRT, IMRT reduced the volume of rectum receiving 45 Gy by 90% (p < 0.001). Overall, 9 patients (33%) experienced acute Grade 2 gastrointestinal (GI) toxicity, and only 1 of these patients was treated with IMRT. Antidiarrhea medication was required for 6 patients (22%). However, 5 of these 6 patients also received chemotherapy, and none were treated with IMRT. No Grade 3 or higher acute or late GI toxicities were observed. No cases of late radiation enteritis were observed. Acute and late genitourinary toxicity did not appear significantly increased by the addition of conformal WPRT. CONCLUSIONS: Compared to conventional 2D planning, conformal planning for WPRT resulted in significant reductions in the doses delivered to the bowel, rectum, and bladder. IMRT was superior to 3D-CRT in limiting the volume of bowel and rectum within high-dose regions. These dosimetric findings correlated with low rates of acute and late GI morbidity.

Adult↗

PubMed2005

Correlation of dosimetric factors and radiation pneumonitis for non-small-cell lung cancer patients in a recently completed dose escalation study.

PURPOSE: To determine dosimetric factors for lung, lung subregions, and heart that correlate with radiation pneumonitis (Radiation Therapy Oncology Group Grade 3 or more) in the 78 evaluable patients from a Phase I dose escalation study (1991-2003) of three-dimensional conformal radiation therapy (3D-CRT) of non-small-cell lung cancer. METHODS AND MATERIALS: There were 10 > or = Grade 3 pneumonitis cases within 6 months after treatment. Dose-volume factors analyzed for univariate correlation with > or = Grade 3 pneumonitis were mean dose (MD), effective uniform dose (d(eff)), normal tissue complication probability (NTCP), parallel model f(dam) and V(D) for 5 < or = D < or = 60 Gy for whole, ipsilateral, contralateral, upper and lower halves of the lungs and heart D05, and mean and maximum doses. RESULTS: The most significant variables (0.005 < p < 0.006) were ipsilateral lung V(D) for D < 20 Gy. Also significant (p < 0.05) for ipsilateral lung were V(D) for D < 50 Gy, MD, f(dam) and d(eff); for total lung V(D) (D < 50 Gy), MD, f(dam), d(eff) and NTCP; for lower lung V(D) (D < 60 Gy), MD, f(dam) and d(eff). All variables for upper and contralateral lung were insignificant, as were heart variables. CONCLUSIONS: Previously reported correlations between severe pneumonitis and whole lung V13 and with other dose-volume factors of total lung and lower lung are confirmed. The most significant correlations were for (V05-V13) in ipsilateral lung.

Adult↗

PubMed2005

Results of a phase I dose-escalation study using three-dimensional conformal radiotherapy in the treatment of inoperable nonsmall cell lung carcinoma.

BACKGROUND: The objective of this study was to report the results of a Phase I dose-escalation study using three-dimensional conformal radiation therapy (3D-CRT) for the treatment of patients with nonsmall cell lung carcinoma (NSCLC). METHODS: Between 1991 and 2003, 104 patients were enrolled for 3D-CRT at Memorial Sloan-Kettering Cancer Center. The median patient age was 69 years. Twenty-eight percent of patients had Stage I-II NSCLC, 33% of patients had Stage IIIA NSCLC, 32% of patients had Stage IIIB NSCLC, and 6% of patients had recurrent NSCLC. Induction chemotherapy was received by 16% of patients. Radiation was delivered in daily fractions of 1.8 grays (Gy) for doses < or = 81.0 Gy and in daily fractions of 2.0 Gy for higher doses. Accrual at a dose level was complete when 10 patients received the intended dose without unacceptable acute morbidity. RESULTS: After an incident of fatal acute radiation pneumonitis at the starting dose of 70.2 Gy, the protocol was modified to limit normal tissue complication probabilities (NTCP) to < 25%. The dose was then escalated from 70.2 Gy, to 75.6 Gy, 81.0 Gy, and 84.0 Gy, with at least 10 patients treated at each dose level. Unacceptable pulmonary toxicity occurred at 90.0 Gy. Subsequently, another 10 patients were accrued at the 84.0 Gy level with acceptable toxicity. Thus, 84.0 Gy was the maximum tolerated dose (MTD). The crude late pulmonary toxicity rate was 7%, the 2-year local control rate was 52%, the disease-free survival rate was 33%, and the overall survival rate was 40%. The median survival was 21.1 months. Overall survival was improved significantly in patients who received > or = 80.0 Gy. CONCLUSIONS: The MTD of 3D-CRT for NSCLC with an NTCP constraint of 25% was 84.0 Gy in the current study. There was a suggestion of improved survival in patients who received 80.0 Gy.

Adult↗

PubMed2005

Multifractionated image-guided and stereotactic intensity-modulated radiotherapy of paraspinal tumors: a preliminary report.

PURPOSE: The use of image-guided and stereotactic intensity-modulated radiotherapy (IMRT) techniques have made the delivery of high-dose radiation to lesions within close proximity to the spinal cord feasible. This report presents clinical and physical data regarding the use of IMRT coupled with noninvasive body frames (stereotactic and image-guided) for multifractionated radiotherapy. METHODS AND MATERIALS: The Memorial Sloan-Kettering Cancer Center (Memorial) stereotactic body frame (MSBF) and Memorial body cradle (MBC) have been developed as noninvasive immobilizing devices for paraspinal IMRT using stereotactic (MSBF) and image-guided (MBC) techniques. Patients were either previously irradiated or prescribed doses beyond spinal cord tolerance (54 Gy in standard fractionation) and had unresectable gross disease involving the spinal canal. The planning target volume (PTV) was the gross tumor volume with a 1 cm margin. The PTV was not allowed to include the spinal cord contour. All treatment planning was performed using software developed within the institution. Isocenter verification was performed with an in-room computed tomography scan (MSBF) or electronic portal imaging devices, or both. Patients were followed up with serial magnetic resonance imaging every 3-4 months, and no patients were lost to follow-up. Kaplan-Meier statistics were used for analysis of clinical data. RESULTS: Both the MSBF and MBC were able to provide setup accuracy within 2 mm. With a median follow-up of 11 months, 35 patients (14 primary and 21 secondary malignancies) underwent treatment. The median dose previously received was 3000 cGy in 10 fractions. The median dose prescribed for these patients was 2000 cGy/5 fractions (2000-3000 cGy), which provided a median PTV V100 of 88%. In previously unirradiated patients, the median prescribed dose was 7000 cGy (5940-7000 cGy) with a median PTV V100 of 90%. The median Dmax to the cord was 34% and 68% for previously irradiated and never irradiated patients, respectively. More than 90% of patients experienced palliation from pain, weakness, or paresthesia; 75% and 81% of secondary and primary lesions, respectively, exhibited local control at the time of last follow-up. No cases of radiation-induced myelopathy or radiculopathy have thus far been encountered. CONCLUSIONS: Precision stereotactic and image-guided paraspinal IMRT allows the delivery of high doses of radiation in multiple fractions to tumors within close proximity to the spinal cord while respecting cord tolerance. Although preliminary, the clinical results are encouraging.

Adult↗

PubMed2005

Does registration of PET and planning CT images decrease interobserver and intraobserver variation in delineating tumor volumes for non-small-cell lung cancer?

PURPOSE: To compare tumor volume delineation using registered positron emission tomography (PET)/CT vs. side-by-side image sets. METHODS AND MATERIALS: A total of 19 patients with non-small-cell lung cancer had 18-fluorine-deoxyglucose (FDG)-PET scans registered with planning CT scans. The disease was Stage I-II in 26%, IIIA in 42%, and IIIB in 32%. Two radiation oncologists contoured 9 tumor volumes using registered images (registered) and 10 using separate FDG-PET images as a guide (nonregistered). A third physician, who had done the treatment planning for these patients a median of 40 months before using registered images, repeated all contours: 10 on registered images (registered/registered) and 9 without registration (registered/nonregistered). Each pair of volumes (A and B) was compared. Quantitative comparison used the concordance index, (A intersection B)/(A union or logical sum B). For qualitative analysis, pairs of volumes were projected onto digitally reconstructed radiographs. The differences were graded as insignificant, minor, moderate, or major. RESULTS: The median interobserver percentage of concordance among nonregistered pairs was 61% vs. 70% in the registered group (p <0.05). On qualitative analysis, in the nonregistered group, the differences were insignificant in 5, minor in 3, and moderate in 2 of 10. The differences in the registered group were insignificant in 7 and minor in 2 of 9. The median intraobserver percentage of concordance in the registered/nonregistered group was 58% vs. 71% in the registered/registered group (p = 0.10). On qualitative analysis, the intraobserver differences in the registered/nonregistered group were insignificant in 2, minor in 2, moderate in 0, and major in 5 of 9. In the registered/registered group, the differences were insignificant in 2, minor in 6, moderate in 2, and major in 0 of 10. CONCLUSION: Registration of FDG-PET and planning CT images results in greater consistency in tumor volume delineation.

Adult↗

PubMed2005

Outcome predictors for the increasing PSA state after definitive external-beam radiotherapy for prostate cancer.

PURPOSE: To identify predictors of distant metastases (DM) among patients who develop an isolated prostate-specific antigen (PSA) relapse after definitive external-beam radiotherapy for clinically localized prostate cancer. MATERIALS AND METHODS: A total of 1,650 patients with clinical stage T1 to T3 prostate cancer were treated with high-dose three-dimensional conformal radiotherapy. Of these, 381 patients subsequently developed three consecutive increasing PSA values and were characterized as having a biochemical relapse. The median follow-up time was 92 months from the completion of radiotherapy. RESULTS: The 5-year incidence of DM after an established PSA relapse was 29%. In a multivariate analysis, PSA doubling time (PSA-DT; P < .001), the clinical T stage (P < .001), and Gleason score (P = .007) were independent variables predicting for DM after established biochemical failure. The PSA-DT for favorable-, intermediate-, and unfavorable-risk patients who developed a biochemical failure was 20.0, 13.2, and 8.2 months, respectively (P < .001). The 3-year incidence of DM for patients with PSA-DT of 0 to 3, 3 to 6, 6 to 12, and more than 12 months was 49%, 41%, 20%, and 7%, respectively (P < .001). Patients with PSA-DT of 0 to 3 and 3 to 6 months demonstrated a 7.0 and 6.6 increased hazard of developing DM or death, respectively, compared with patients with a DT more than 12 months. CONCLUSION: In addition to clinical stage and Gleason score, PSA-DT was a powerful predictor of DM among patients who develop an isolated PSA relapse after external-beam radiotherapy for prostate cancer. Patients who develop biochemical relapse with PSA-DT < or = 6 months should be considered for systemic therapy or experimental protocols because of the high propensity for rapid DM development.

Adult↗

PubMed2005

Tumor motion control in the treatment of non small cell lung cancer.

Tumor motion due to respiration during radiation therapy for non-small cell lung cancer is a significant problem. This article reports on two techniques used to control tumor motion: respiratory gating and the deep inspiration breath hold technique. This technique was implemented in 40 patients without significant difficulties and there are encouraging clinical outcomes.

Carcinoma, Non-Small-Cell Lung↗

PubMed2004

Improved local control with higher doses of radiation in large-volume stage III non-small-cell lung cancer.

PURPOSE: It has been suggested that larger tumor volume is associated with poor survival in patients with non-small-cell lung cancer (NSCLC). We investigated whether high-dose radiation improved local control in patients with large-volume Stage III NSCLC. METHODS AND MATERIALS: Seventy-two patients with Stage III NSCLC and gross tumor volumes (GTV) of greater than 100 cc were treated with three-dimensional conformal radiotherapy (3D-CRT). Patients were divided into two groups: those treated to less than 64 Gy (37 patients) and those treated to 64 Gy or higher (35 patients). RESULTS: The 1-year and 2-year local failure rates were 27% and 47%, respectively, for Stage III patients treated to 64 Gy or higher, and 61% and 76%, respectively, for those treated to less than 64 Gy (p = 0.024). The median survival time for patients treated to 64 Gy or higher was 20 months vs. 15 months for those treated to less than 64 Gy (p = 0.068). Multivariate analysis revealed that dose and GTV are predictors of local failure-free survival. A 10 Gy increase in dose resulted in a 36.4% decreased risk of local failure. CONCLUSIONS: Our data suggest that administration of higher doses using 3D-CRT improves local control in Stage III NSCLC patients with large GTVs.

Adult↗

PubMed2004

Intensity-modulated radiotherapy for soft tissue sarcoma of the thigh.

PURPOSE: Fracture of the femur is one of the late complications of adjuvant radiotherapy for patients with soft tissue sarcomas of the thigh, who receive external beam irradiation after limb-sparing surgery. When the target volume approximates the femur, it is often inevitable that a large segment of the femur will receive full prescription dose with conventional radiation techniques. We report the dosimetric feasibility of intensity- modulated radiation therapy (IMRT) techniques to achieve adequate target coverage and bone sparing. METHODS AND MATERIALS: Treatment planning was performed using both three-dimensional conformal radiotherapy (3D-CRT) and IMRT techniques for 10 patients with soft tissue sarcoma of the thigh with tumor approaching the femur. None of the patients had bony involvement. For all patients, the gross total volume (GTV) and the femur were contoured. The clinical target volume (CTV) was defined as the GTV with a 1.5-cm margin axially, except at the bone interface where the bone interface was used as CTV if the 1.5-cm axial margin extended beyond the bone interface. In the superior-inferior direction, the CTV margin placed around the GTV varied from 5 to 10 cm. The planning target volume (PTV) was defined as the CTV with 5-mm margin all around. The 3D conformal technique consisted primarily of two to three beams with wedges or partial transmission blocks as compensators. For the IMRT technique, five coplanar beams were used, chosen so as to spare much of the surrounding soft tissue and to clear the other extremity or groin areas. IMRT plans were designed to adequately treat the planning target volume and spare the femur as much as possible. RESULTS: Dose distributions and dose-volume histograms were analyzed. PTV coverage was comparable with both IMRT and 3D-CRT plans. Dose distributions were more conformal with IMRT, however, especially for patients with large variations of contours. The volume of the femur receiving at least full prescription (63 Gy) V100 decreased on average by approximately 57%, from 44.7 +/- 16.8% with 3D-CRT to 18.6 +/- 9.2% with IMRT (p < 0.01). For 3 patients with a GTV surrounding <50% of the circumference of the femur, the reduction in the V100 to the femur ranged from 61% to 79%. The hot spots in the femur, as measured by D05 (the dose encompassing 5% of volume), reduced on average from 67.2 +/- 1.8 Gy with 3D-CRT to 65.0 +/- 1.2 Gy with IMRT (p < 0.01). The mean dose to the femur was on average 38.5 +/- 11.5 Gy with IMRT, compared with 40.9 +/- 12.7 Gy with 3D-CRT. The volume of the surrounding soft tissues, defined as the ipsilateral limb excluding the PTV and the femur, receiving at least prescription dose (63 Gy) was reduced on average by about 78%, from 997 +/- 660 cc with 3D-CRT to 201 +/- 144 cc with IMRT (p < 0.01). The D05 to the surrounding soft tissues was on average 58.7 +/- 4.7 Gy with IMRT, compared to 67.8 +/- 1.3 Gy with 3D-CRT (p < 0.01), a reduction of approximately 13%. The mean dose to the surrounding soft tissues was comparable in both plans. The volume of the skin (from surface to 5 mm depth) receiving prescription dose (63 Gy) declined by roughly 45%, from 115 +/- 40 cc with 3D-CRT to 61 +/- 20 cc with IMRT (p < 0.01), with IMRT providing full skin dose coverage to scars. The hot spots in the skin decreased from 68.0 +/- 1.7 Gy with 3D-CRT to 65.2 +/- 1.2 Gy with IMRT (p < 0.01). The mean dose to the skin lessened from 51.5 +/- 4.7 Gy with 3D- CRT to 44.0 +/- 4.2 Gy with IMRT (p < 0.01), a reduction of 14%. CONCLUSIONS: Intensity-modulated radiation therapy techniques can reduce the dose to the femur without compromising target coverage by achieving concave dose distributions around the interface of the PTV and the femur. At the same time, IMRT can reduce the hot spots significantly in the surrounding soft tissues and skin. Whether such dosimetric improvements can translate into reduction of complications and/or improving local control needs to be investigated.

Femur↗

PubMed2004

Salvage radiotherapy for recurrent prostate cancer after radical prostatectomy.

CONTEXT: Salvage radiotherapy may potentially cure patients with disease recurrence after radical prostatectomy, but previous evidence has suggested that it is ineffective in patients at the highest risk of metastatic disease progression. OBJECTIVE: To delineate patients who may benefit from salvage radiotherapy for prostate cancer recurrence by identifying variables associated with a durable response. DESIGN, SETTING, AND PATIENTS: Retrospective review of a cohort of 501 patients at 5 US academic tertiary referral centers who received salvage radiotherapy between June 1987 and November 2002 for detectable and increasing prostate-specific antigen (PSA) levels after radical prostatectomy. MAIN OUTCOME MEASURE: Disease progression after salvage radiotherapy, defined as a serum PSA value > or =0.1 ng/mL above the postradiotherapy PSA nadir confirmed by a second PSA measurement that was higher than the first by any amount, by a continued increase in PSA level after treatment, or by the initiation of androgen deprivation therapy after treatment. RESULTS: Over a median follow-up of 45 months, 250 patients (50%) experienced disease progression after treatment, 49 (10%) developed distant metastases, 20 (4%) died from prostate cancer, and 21 (4%) died from other or unknown causes. The 4-year progression-free probability (PFP) was 45% (95% confidence interval [CI], 40%-50%). By multivariable analysis, predictors of progression were Gleason score of 8 to 10 (hazard ratio [HR], 2.6; 95% CI, 1.7-4.1; P<.001), preradiotherapy PSA level greater than 2.0 ng/mL (HR, 2.3; 95% CI, 1.7-3.2; P<.001), negative surgical margins (HR, 1.9; 95% CI, 1.4-2.5; P<.001), PSA doubling time (PSADT) of 10 months or less (HR, 1.7; 95% CI, 1.2-2.2; P =.001), and seminal vesicle invasion (HR, 1.4; 95% CI, 1.1-1.9; P =.02). Patients with no adverse features had a 4-year PFP of 77% (95% CI, 64%-91%). When treatment was given for early recurrence (PSA level < or =2.0 ng/mL), patients with Gleason scores of 4 to 7 and a rapid PSADT had a 4-year PFP of 64% (95% CI, 51%-76%) and of 22% (95% CI, 6%-38%) when the surgical margins were positive and negative, respectively. Patients with Gleason scores of 8 to 10, positive margins, and receiving early salvage radiotherapy had a 4-year PFP of 81% (95% CI, 57%-100%) when the PSADT was longer than 10 months and of 37% (95% CI, 16%-58%) when the PSADT was 10 months or less. CONCLUSIONS: Gleason score, preradiotherapy PSA level, surgical margins, PSADT, and seminal vesicle invasion are prognostic variables for a durable response to salvage radiotherapy. Selected patients with high-grade disease and/or a rapid PSADT who were previously thought to be destined to develop progressive metastatic disease may achieve a durable response to salvage radiotherapy.

Adult↗

PubMed2004

Five-year outcomes after neoadjuvant chemotherapy and conformal radiotherapy in patients with high-risk localized prostate cancer.

OBJECTIVES: To describe the 5-year outcomes of patients with high-risk localized prostate cancer treated with neoadjuvant estramustine and vinblastine followed by concurrent chemotherapy and three-dimensional conformal radiotherapy (3D-CRT). METHODS: A total of 23 patients completed therapy consisting of two 8-week cycles of vinblastine, weekly as 4 mg/m2, followed by 8 weeks of concomitant chemotherapy and 3D-CRT. Estramustine was given daily at 10 mg/kg in three divided doses. 3D-CRT consisted of a total dose of 7560 cGy. RESULTS: Assessable patients include 9 with Stage T3 or greater tumors and 5 with lymph node metastasis at diagnosis. All patients had a Gleason score 7 or greater. The median follow-up was 60 months. Of the 23 assessable patients, 15 (65%) experienced biochemical relapse by American Society for Therapeutic Radiology Oncology criteria. The median time to prostate-specific antigen relapse was 12 months (range 7 to 16). Five patients (22%) developed metastases. The median time to metastasis had not been reached by last follow-up. Of the 23 assessable patients, 11 (48%) received no additional therapy and had noncastrate testosterone levels. Six patients had no evidence of disease and 9 patients were receiving androgen blockade. Three patients died (one of prostate cancer and two of other diseases). CONCLUSIONS: A substantial proportion of patients with unfavorable-risk localized prostate cancer achieved long-term disease control with estramustine and vinblastine and concurrent 3D-CRT, no significant long-term toxicities were seen and 48% underwent no further therapy after RT. These long-term findings support the continued study of chemotherapy combined with RT as a potential alternative to prolonged androgen deprivation.

Adenocarcinoma↗

PubMed2004

Intensity-modulated stereotactic radiotherapy of paraspinal tumors: a preliminary report.

OBJECTIVE: Radioresistant paraspinal tumors may benefit from conformal treatment techniques such as intensity-modulated radiotherapy (IMRT). Local tumor control and long-term palliation for both primary and metastatic tumors may be achieved with IMRT while reducing the risk of spinal cord toxicity associated with conventional radiotherapy techniques. In this article, we report our initial clinical experience in treating 16 paraspinal tumors with IMRT in which the planning target volume was 2 mm or greater from the spinal cord. METHODS: IMRT was administered by using a linear accelerator mounted with a multileaf collimator. Two immobilization body frames developed at Memorial Sloan-Kettering Cancer Center were used for patients with and without spinal implants. During a 30-month period, 16 patients underwent IMRT for metastatic and primary tumors. Eleven patients were treated for symptomatic recurrences after undergoing surgery and prior external beam radiotherapy, and one patient was treated after undergoing radiotherapy for a metastatic pancreatic gastrinoma with overlapping ports to the spine. Four patients with primary tumors were treated after primary resection that resulted in positive histological margins. Twelve patients were symptomatic with pain, functional radiculopathy, or both. Tumoral doses were determined on the basis of the relative radiosensitivity of tumors. Patients with metastatic tumors were administered a median tumoral dose of 20 Gy in four to five fractions and a spinal cord maximum dose of 6.0 Gy in addition to the full tolerance dose administered in previous radiation treatments. The primary tumors were delivered a median dose of 70 Gy in 33 to 37 fractions and a spinal cord maximum dose of 16 Gy. The median tumoral volume was 7.8 cm(3). RESULTS: Of the 15 patients who underwent radiographic follow-up, 13 demonstrated either no interval growth or a reduction in tumor size in a median follow-up period of 12 months (range, 2-23 mo). Two patients, one with a thoracic chondrosarcoma and one with a chordoma, showed tumor progression 1 year after undergoing IMRT. Pain symptoms improved in 11 of 11 patients, and 4 of 4 patients had significant improvement in their functionally significant radiculopathy and/or plexopathy. Pain relief was durable in all patients except the two with tumor progression. No patient showed signs or symptoms of radiation-induced myelopathy, radiculopathy, or plexopathy, including 12 patients with a median follow-up of 18 months. CONCLUSION: IMRT was effective for treating pain and improving functional radiculopathy in patients with metastatic and primary tumors. Although long-term tumor control is not established in this study, high-dose tumoral irradiation can be performed without causing radiation myelopathy in more than 1 year of follow-up.

Adult↗

PubMed2003

Pretreatment nomogram that predicts 5-year probability of metastasis following three-dimensional conformal radiation therapy for localized prostate cancer.

PURPOSE: There are several nomograms for the patient considering radiation therapy for clinically localized prostate cancer. Because of the questionable clinical implications of prostate-specific antigen (PSA) recurrence, its use as an end point has been criticized in several of these nomograms. The goal of this study was to create and to externally validate a nomogram for predicting the probability that a patient will develop metastasis within 5 years after three-dimensional conformal radiation therapy (CRT). PATIENTS AND METHODS: We conducted a retrospective, nonrandomized analysis of 1,677 patients treated with three-dimensional CRT at Memorial Sloan-Kettering Cancer Center (MSKCC) from 1988 to 2000. Clinical parameters examined were pretreatment PSA level, clinical stage, and biopsy Gleason sum. Patients were followed until their deaths, and the time at which they developed metastasis was noted. A nomogram for predicting the 5-year probability of developing metastasis was constructed from the MSKCC cohort and validated using the Cleveland Clinic series of 1,626 patients. RESULTS: After three-dimensional CRT, 159 patients developed metastasis. At 5 years, 11% of patients experienced metastasis by cumulative incidence analysis (95% CI, 9% to 13%). A nomogram constructed from the data gathered from these men showed an excellent ability to discriminate among patients in an external validation data set, as shown by a concordance index of 0.81. CONCLUSION: A nomogram with reasonable accuracy and discrimination has been constructed and validated using an external data set to predict the probability that a patient will experience metastasis within 5 years after three-dimensional CRT.

Adenocarcinoma↗

PubMed2003

Patterns of failure using a conformal radiation therapy tumor bed boost for medulloblastoma.

PURPOSE: To assess the patterns of failure for patients with medulloblastoma receiving a conformal tumor bed boost rather than a boost to the entire posterior fossa. PATIENTS AND METHODS: From 1994 to 2002, 32 consecutive patients with newly diagnosed medulloblastoma treated at Memorial Sloan-Kettering Cancer Center (New York, NY) received a conformal boost to the tumor bed in conjunction with craniospinal radiation therapy. Twenty-eight patients also received chemotherapy. The median age was 9 years (range, 3 to 34 years), and the male to female ratio was 3:1. Twenty-seven patients had standard-risk disease, and five patients had high-risk disease. Craniospinal doses ranged from 23.4 to 39.6 Gy, and total tumor bed doses ranged from 54 to 59.4 Gy. RESULTS: With a median follow-up of 56 months, six patients have relapsed; five relapsed outside of the posterior fossa, and one failed within the posterior fossa, outside of the high-dose boost volume. Five-year actuarial disease-free and overall survival rates were 84% and 85%, respectively. Freedom from posterior fossa failure was 100% and 86% at 5 and 10 years, respectively. Freedom from distant failure was 84% at 5 years, with a trend for improvement when full-dose craniospinal radiation (36 to 39.6 Gy) was used compared with a reduced dose (23.4 Gy) of radiation (100% v 63%, respectively; P =.06). No other predictive variables were identified. CONCLUSION: Conformal treatment to the tumor bed allows for significant sparing of critical structures. The posterior fossa failure rate in this series is similar to that reported when the entire posterior fossa is treated. This approach should be investigated further in a phase III trial.

Adolescent↗

PubMed2003

The prognostic significance of Gleason Grade in patients treated with permanent prostate brachytherapy.

PURPOSE: To assess the difference in biochemical freedom from relapse (BFR) between patients with clinically localized prostate cancer having Gleason Grade (GG) 3 + 4 vs. 4 + 3 disease treated with permanent prostate brachytherapy (PPB). METHODS AND MATERIALS: One thousand twenty-nine consecutive T1/T2 patients underwent PPB with Gleason sum 6, 7, or 8 adenocarcinoma of the prostate. Treatment consisted of transperineal ultrasound-guided implant as monotherapy or in combination with external beam radiation and/or neoadjuvant androgen ablation (NAAD). The Kattan modification of the ASTRO consensus definition that censors patients with rising follow-up PSA values early was used to measure BFR. Kaplan-Meier actuarial survival was calculated and compared using the log-rank test. Cox proportional hazards regression was performed to assess the role of Gleason grade, initial PSA value, stage, the addition of external beam radiotherapy, and the addition of NAAD. RESULTS: The median follow-up for all 1029 patients is 46 months (range: 3-108 months) with a BFR at 5 years of 78.2% and at 7 years of 76.2%. The 7-year BFR for patients with GG 3 + 3 was 81.8%, GG 3 + 4 was 78.4%, GG 4 + 3 was 56.7%, and GG 4 + 4 was 50.7% (p < 0.0001). Cox regression analysis identified that the Gleason grade (p < 0.0001), initial PSA value (p = 0.001), D90% (p < 0.0001), and clinical stage (p = 0.016) were associated with biochemical recurrence, whereas NAAD (p = 0.057) and external beam radiotherapy (p = 0.356) were not. CONCLUSIONS: Gleason sum 7 tumors in patients treated with PPB represent a heterogeneous group of patients based on the differentiation of Gleason Grade 3 + 4 tumors vs. 4 + 3 disease. This information confirms similar conclusions identified in patients treated with external beam radiation and is useful when determining prognosis after PPB.

Adenocarcinoma↗

PubMed2003

Adenovirus-mediated heat-activated antisense Ku70 expression radiosensitizes tumor cells in vitro and in vivo.

Ku70 is one component of a protein complex, Ku70 and Ku80, that functions as a heterodimer to bind DNA double-strand breaks and activates DNA-dependent protein kinase. Our previous study with Ku70-/- and Ku80-/- mice, and cell lines has shown that Ku70- and Ku80-deficiency compromises the ability of cells to repair DNA double-strand breaks, increases radiosensitivity of cells, and enhances radiation-induced apoptosis. In this study, we examined the feasibility of using adenovirus-mediated, heat-activated expression of antisense Ku70 RNA as a gene therapy paradigm to sensitize cells and tumors to ionizing radiation. First, we performed experiments to test the heat inducibility of heat shock protein (hsp) 70 promoter and the efficiency of adenovirus-mediated gene transfer in rodent and human cells. Replication-defective adenovirus vectors were used to introduce a recombinant DNA construct, containing the enhanced green fluorescent protein (EGFP) under the control of an inducible hsp70 promoter, into exponentially growing cells. At 24 h after infection, cells were exposed to heat treatment, and heat-induced EGFP expression at different times was determined by flow cytometry. Our data clearly show that heat shock at 42 degrees C, 43 degrees C, or 44 degrees C appears to be equally effective in activating the hsp70 promoter-driven EGFP expression (>300-fold) in various tumor cells. Second, we have generated adenovirus vectors containing antisense Ku70 under the control of an inducible hsp70 promoter. Exponentially growing cells were infected with the adenovirus vector, heat shocked 24 h later, and the radiosensitivity determined 12 h after heat shock. Our data show that heat shock induces antisense Ku70 RNA, reduces the endogenous Ku70 level, and significantly increases the radiosensitivity of the cells. Third, we have performed studies to test whether Ku70 protein level can be down-regulated in a solid mouse tumor (FSa-II), and whether this results in enhanced radiosensitivity in vivo, as assessed by in vivo/in vitro colony formation and by the tumor growth delay. Our data demonstrate that heat-shock-induced expression of antisense Ku70 RNA attenuates Ku70 protein expression in FSa-II tumors, and significantly sensitizes the FSa-II tumors to ionizing radiation. Taken together, our results suggest that adenovirus-mediated, heat-activated antisense Ku70 expression may provide a novel approach to radiosensitize human tumors.

Adenocarcinoma↗

PubMed2003

Predictors of biochemical outcome with salvage conformal radiotherapy after radical prostatectomy for prostate cancer.

PURPOSE: To identify predictors of biochemical outcome following radiotherapy in patients with a rising prostate-specific antigen (PSA) after radical prostatectomy for prostate cancer. PATIENTS AND METHODS: One hundred fifteen patients with a rising PSA after radical prostatectomy received salvage three-dimensional conformal radiotherapy (3D-CRT) alone or with neoadjuvant androgen deprivation. Tumor-related and treatment-related factors were evaluated to identify predictors of subsequent PSA failure. RESULTS: The median follow-up time after 3D-CRT was 42 months. The 4-year actuarial PSA relapse-free survival, distant metastasis-free survival, and overall survival rates were 46%, 83%, and 95%, respectively. Multivariate analysis, which was limited to 70 patients receiving radiation without androgen deprivation therapy, showed that negative/close margins (P =.03), absence of extracapsular extension (P <.01), and presence of seminal vesicle invasion (P <.01) were independent predictors of PSA relapse after radiotherapy. Neoadjuvant androgen deprivation did not improve the 4-year PSA relapse-free survival in patients with positive margins, extracapsular extension, and no seminal vesicle invasion (P =.24). However, neoadjuvant androgen deprivation did improve PSA relapse-free survival when one or more of these variables were absent (P =.03). CONCLUSIONS: Salvage 3D-CRT can provide biochemical control in selected patients with a rising PSA after radical prostatectomy. Among patients with positive margins and no poor prognostic features, 77% achieved PSA control after salvage 3D-CRT. Salvage neoadjuvant androgen deprivation therapy may improve short-term biochemical control, but it requires further study.

Adult↗