Defining biochemical failure following radiotherapy with or without hormonal therapy in men with clinically localized prostate cancer: recommendations of the RTOG-ASTRO Phoenix Consensus Conference

In 1996 the American Society for Therapeutic Radiology and Oncology (ASTRO) sponsored a Consensus Conference to establish a definition of biochemical failure after external beam radiotherapy (EBRT). The ASTRO definition defined prostate specific antigen (PSA) failure as occurring after three consecutive PSA rises after a nadir with the date of failure as the point halfway between the nadir date and the first rise or any rise great enough to provoke initiation of therapy. This definition was not linked to clinical progression or survival; it performed poorly in patients undergoing hormonal therapy (HT), and backdating biased the Kaplan-Meier estimates of event-free survival. A second Consensus Conference was sponsored by ASTRO and the Radiation Therapy Oncology Group in Phoenix, Arizona, on January 21, 2005, to revise the ASTRO definition. The panel recommended: (1) a rise by 2 ng/mL or more above the nadir PSA be considered the standard definition for biochemical failure after EBRT with or without HT; (2) the date of failure be determined "at call" (not backdated). They recommended that investigators be allowed to use the ASTRO Consensus Definition after EBRT alone (no hormonal therapy) with strict adherence to guidelines as to "adequate follow-up." To avoid the artifacts resulting from short follow-up, the reported date of control should be listed as 2 years short of the median follow-up. For example, if the median follow-up is 5 years, control rates at 3 years should be cited. Retaining a strict version of the ASTRO definition would allow comparisons with a large existing body of literature.

Ten-year follow-up of radiation therapy oncology group protocol 92-02: a phase III trial of the duration of elective androgen deprivation in locally advanced prostate cancer

PURPOSE

To determine whether adding 2 years of androgen-deprivation therapy (ADT) improved outcome for patients electively treated with ADT before and during radiation therapy (RT).

PATIENTS AND METHODS

Prostate cancer patients with T2c-T4 prostate cancer with no extra pelvic lymph node involvement and prostate-specific antigen (PSA) less than 150 ng/mL were included. All patients received 4 months of goserelin and flutamide before and during RT. They were randomized to no further ADT (short-term ADT [STAD] + RT) or 24 months of goserelin (long-term ADT [LTAD] + RT). A total of 1,554 patients were entered. RT was 45 Gy to the pelvic nodes and 65 to 70 Gy to the prostate. Median follow-up of all survival patients is 11.31 and 11.27 years for the two arms.

RESULTS

At 10 years, the LTAD + RT group showed significant improvement over the STAD + RT group for all end points except overall survival: disease-free survival (13.2% v 22.5%; P < .0001), disease-specific survival (83.9% v 88.7%; P = .0042), local progression (22.2% v 12.3%; P < .0001), distant metastasis (22.8% v 14.8%; P < .0001), biochemical failure (68.1% v 51.9%; P <or= .0001), and overall survival (51.6% v 53.9%, P = .36). One subgroup analyzed consisted of all cancers with a Gleason score of 8 to 10 cancers. An overall survival difference was observed (31.9% v 45.1%; P = .0061), as well as in all other end points herein.

CONCLUSION

LTAD as delivered in this study for the treatment of locally advanced prostate cancer is superior to STAD for all end points except survival. A survival advantage for LTAD + RT in the treatment of locally advanced tumors with a Gleason score of 8 to 10 suggests that this should be the standard of treatment for these high-risk patients.

Phase III trial of long-term adjuvant androgen deprivation after neoadjuvant hormonal cytoreduction and radiotherapy in locally advanced carcinoma of the prostate: the Radiation Therapy Oncology Group Protocol 92-02

PURPOSE

Radiation Therapy Oncology Group (RTOG) Protocol 92-02 was a randomized trial testing long-term (LT) adjuvant androgen deprivation (AD) after initial AD with external-beam radiotherapy (RT) in patients with locally advanced prostate cancer (PC; T2c-4) and with prostate-specific antigen level less than 150 ng/mL.

PATIENTS AND METHODS

Patients received a total of 4 months of goserelin and flutamide, 2 months before and 2 months during RT. A radiation dose of 65 to 70 Gy was given to the prostate and a dose of 44 to 50 Gy to the pelvic lymph nodes. Patients were randomly assigned to receive no additional therapy (short-term [ST]AD-RT) or 24 months of goserelin (LTAD-RT); 1,554 patients were entered onto the study.

RESULTS

The LTAD-RT arm showed significant improvement in all efficacy end points except overall survival (OS; 80.0% v 78.5% at 5 years, P =.73), compared with the STAD-RT arm. In a subset of patients not part of the original study design, with tumors assigned Gleason scores of 8 to 10 by the contributing institutions, the LTAD-RT arm had significantly better OS (81.0% v 70.7%, P =.044). There was a small but significant increase in the frequency of late radiation grades 3, 4, and 5 gastrointestinal toxicity ascribed to the LTAD-RT arm (2.6% v 1.2% at 5 years, P =.037), the cause of which is not clear.

CONCLUSION

The RTOG 92-02 trial supports the addition of LT adjuvant AD to STAD with RT for T2c-4 PC. In the exploratory subset analysis of patients with Gleason scores 8 to 10, LT adjuvant AD resulted in a survival advantage.

Phase III trial of androgen suppression using goserelin in unfavorable-prognosis carcinoma of the prostate treated with definitive radiotherapy: report of Radiation Therapy Oncology Group Protocol 85-31

PURPOSE

Although androgen suppression results in a tumor response/remission in the majority of patients with carcinoma of the prostate, its potential value as an adjuvant has not been substantiated.

MATERIALS AND METHODS

In 1987, the Radiation Therapy Oncology Group (RTOG) initiated a randomized phase III trial of adjuvant goserelin in definitively irradiated patients with carcinoma of the prostate. A total of 977 patients had been accessioned to the study. Of these, 945 remained analyzable: 477 on the adjuvant arm and 468 on the observation arm.

RESULTS

Actuarial projections show that at 5 years, 84% of patients on the adjuvant goserelin arm and 71% on the observation arm remain without evidence of local recurrence (P < .0001). The corresponding figures for freedom from distant metastases and disease-free survival are 83% versus 70% (P < .001) and 60% and 44% (P < .0001). If prostate-specific antigen (PSA) level greater than 1.5 ng is included as a failure (after > or = 1 year), the 5-year disease-free survival rate on the adjuvant goserelin arm is 53% versus 20% on the observation arm (P < .0001). The 5-year survival rate (for the entire population) is 75% on the adjuvant arm versus 71% on the observation arm (P = .52). However, in patients with centrally reviewed tumors with a Gleason score of 8 to 10, the difference in actuarial 5-year survival (66% on the adjuvant goserelin arm v 55% on the observation arm) reaches statistical significance (P = .03).

CONCLUSION

Application of androgen suppression as an adjuvant to definitive radiotherapy has been associated with a highly significant improvement in local control and freedom from disease progression. At this point, with a median follow-up time of 4.5 years, a significant improvement in survival has been observed only in patients with centrally reviewed tumors with a Gleason score of 8 to 10.

Dose escalation with 3D conformal treatment: five year outcomes, treatment optimization, and future directions

PURPOSE

To report the 5-year outcomes of dose escalation with 3D conformal treatment (3DCRT) of prostate cancer.

METHODS AND MATERIALS

Two hundred thirty-two consecutive patients were treated with 3DCRT alone between 6/89 and 10/92 with ICRU reporting point dose that increased from 63 to 79 Gy. The median follow-up was 60 months, and any patient free of clinical or biochemical evidence of disease was termed bNED. Biochemical failure was defined as prostate-specific antigen (PSA) rising on two consecutive recordings and exceeding 1.5 ng/ml. Morbidity was reported by the Radiation Therapy Oncology Group (RTOG) scale, the Late Effects Normal Tissue (LENT) scale, and a Fox Chase modification of the latter (FC-LENT). All patients were treated with a four-field technique with a 1 cm clinical target volume (CTV) to planning target volume (PTV) margin to the prostate or prostate boost; the CTV and gross tumor volume (GTV) were the same. Actuarial rates of outcome were calculated by Kaplan-Meier and cumulative incidence methods and compared using the log rank and Gray's test statistic, respectively. Cox regression models were used to establish prognostic factors predictive of the various measures of outcome. Five-year Kaplan-Meier bNED rates were utilized by dose group to estimate logit response models for bNED and late morbidity.

RESULTS

PSA <10 ng/ml: No dose response was demonstrated using estimated bNED rates or by analysis of PSA nadir vs. dose. PSA 10-19.9 ng/ml: A bNED dose response was demonstrated (p = 0.02) using the log rank test. The logit response model showed 5-year bNED rates of 35% at 70 Gy and 75% at 76 Gy (p = 0.0049) and illustrated the relative ineffectiveness of conventional dose treatment. PSA 20+ ng/ml: A bNED dose response was demonstrated (p = 0.02) using the log rank test. The logit response model indicated a 5-year bNED rate of 10% at 70 Gy and 32% at 76 Gy (p = 0.10). Morbidity: Dose response was demonstrated for FC-LENT grade 2 and grade 3,4 GI morbidity and for LENT grade 2 GU sequelae. RTOG grade 3,4 GI morbidity at 5 years was <1%. Factors associated with bNED, cause-specific survival, and metastasis were studied using Cox multivariate analysis. Pretreatment PSA (p = 0.0001), Gleason score 7-10 (p = 0.0001), and dose (p = 0.017) were significantly predictive of bNED. For each 1 Gy increase in dose, the hazard of bNED failure decreased by 8%. Palpation stage was associated with cause-specific survival (p = 0.002) and distant metastasis (p = 0.0004). Gleason score was also predictive of distant metastasis (p = 0.02).

CONCLUSIONS

A dose response was observed for patients with pretreatment PSA >10 ng/ml based on 5-year bNED results. No dose response was observed for patients with pretreatment PSA < 10 ng/ml. Dose response was observed for FC-LENT grade 2 and grade 3,4 GI sequelae and for LENT grade 2 GU sequelae. Optimization of treatment was made possible by the results in this report. The improvement in 5-year bNED rates for patients with PSA levels > 10 ng/ml strongly suggests that clinical trials employing radiation should investigate the use of 3DCRT and prostate doses of 76-80 Gy.

Radiation therapy for clinically localized prostate cancer: a multi-institutional pooled analysis

CONTEXT

Prostate-specific antigen (PSA) evaluation leads to the early detection of both prostate cancer and recurrences following primary treatment. Prostate-specific antigen outcome information on patients 5 or more years following treatment is limited and available mainly as single-institution reports.

OBJECTIVES

To assess the likelihood and durability of tumor control using PSA evaluation 5 or more years after radical external beam radiation therapy and to identify pretreatment prognostic factors in men with early prostate cancer treated since 1988, the PSA era.

DESIGN AND SETTING

Retrospective, nonrandomized, multi-institutional pooled analysis of patients treated with external beam radiation therapy alone between 1988 and 1995 at 6 US medical centers. Follow-up lasted up to a maximum of 9 years. Outcome data were analyzed using Cox regression and recursive partitioning techniques.

PATIENTS

A total of 1765 men with stage T1b, T1c, and T2 tumors treated between 1988 and 1995 with external beam radiation. The majority (58%) of patients were older than 70 years and 24.2% had initial PSA values of 20 ng/mL or higher. A minimum of 2 years of subsequent follow-up was required for participation.

MAIN OUTCOME MEASURE

Actuarial estimates of freedom from biochemical failure.

RESULTS

The 5-year estimates of overall survival, disease-specific survival, and the freedom from biochemical failure are 85.0% (95% confidence interval [CI], 82.5%-87.6%), 95.1% (95% CI, 94.0%-96.2%), and 65.8% (95% CI, 62.8%-68.0%), respectively. The PSA failure-free rates 5 and 7 years after treatment for patients presenting with a PSA of less than 10 ng/mL were 77.8% (95% CI, 74.5%-81.3%), and 72.9% (95% CI, 67.9%-78.2%). Recursive partitioning analysis of initial PSA level, palpation stage, and the Gleason score groupings yielded 4 separate prognostic groups: group 1, included patients with a PSA level of less than 9.2 ng/mL; group 2, PSA level of at least 9.2 but less than 19.7 ng/mL; group 3, PSA level at least 19.7 ng/mL and a Gleason score of 2 to 6; and group 4, PSA level of at least 19.7 ng/mL and a Gleason score of 7 to 10. The estimated rates of survival free of biochemical failure at 5 years are 81 % for group 1, 69% for group 2, 47% for group 3, and 29% for group 4. Of the 302 patients followed up beyond 5 years who were free of biochemical disease, 5.0% relapsed from the fifth to the eighth year.

CONCLUSIONS

Estimated PSA control rates in this pooled analysis are similar to those of single institutions. These rates indicate the probability of success for subsets of patients with tumors of several prognostic category groupings. These results represent a multi-institutional benchmark for evidence-based counseling of prostate cancer patients about radiation treatment.

Updated results of the phase III Radiation Therapy Oncology Group (RTOG) trial 85-31 evaluating the potential benefit of androgen suppression following standard radiation therapy for unfavorable prognosis carcinoma of the prostate

PURPOSE

To determine the potential advantage of androgen ablation following standard external-beam radiation therapy in patients with locally advanced (clinical or pathologic T3; clinical or pathologic node positive) carcinoma of the prostate.

METHODS AND MATERIALS

In 1987 the RTOG initiated a Phase III trial of long-term adjuvant goserelin in definitively irradiated patients with carcinoma of the prostate. A total of 977 patients were accrued to the study of which 945 remain analyzable: 477 on the adjuvant hormone arm (Arm I); and 468 on the radiation only arm (Arm II) with hormones initiated at relapse. The initial results were reported in the Journal of Clinical Oncology in 1997.

RESULTS

With a median follow up of 5.6 years for all patients and 6.0 years for living patients local failure at 8 years was 23% for Arm I and 37% for Arm II (p < 0.0001). Distant metastasis was likewise favorably impacted with the immediate use of hormonal manipulation with a distant metastasis rate in Arm I of 27% and 37% in Arm II (p < 0.0001). Disease-free survival (NED survival) and NED survival with PSA of 1.5 ng/mL (bNED) or less were both statistically significant in favor of the immediate hormone arm (both p < 0.0001). Cause-specific failure was not statistically different with a cause-specific failure of 16% for Arm I and 21% in Arm II (p = 0.23). Overall survival was likewise not statistically different between two arms, with a 49% overall survival at 8 years in Arm I and 47% in Arm II (p = 0.36). Subset analysis of centrally reviewed Gleason 8-10 patients who did not undergo prostatectomy showed that for patients receiving radiation therapy plus adjuvant hormones there was a statistically significant improvement in both absolute (p = 0.036) and cause-specific survival (p = 0.019).

CONCLUSIONS

Use of long-term adjuvant androgen deprivation in addition to definitive radiation therapy results in a highly significant improvement in regards to local control, freedom from distant metastasis, and biochemical free survival in unfavorable prognosis patients with carcinoma of the prostate.

Long-term treatment sequelae following external beam irradiation for adenocarcinoma of the prostate: analysis of RTOG studies 7506 and 7706

Significant late intestinal and urinary morbidity from external beam irradiation for adenocarcinoma of the prostate has been a constant concern of both the urologist and the radiation oncologist. We analyzed two large Radiation Therapy Oncology Group trials (7506 and 7706) using primary irradiation in the treatment of local or locoregional adenocarcinoma of the prostate to assess morbidity via the Radiation Therapy Oncology Group scoring scheme (grade 1-5). One thousand twenty patients were treated in total with a minimum follow-up of 7 years in the surviving patients. There was a 3.3% incidence of intestinal complications defined as grade 3 toxicity or more with .6% of patients experiencing bowel obstruction or perforation. Urinary complications defined as grade 3 toxicity or more were found in 7.7% of patients with only 0.5% experiencing morbidity that would require a major surgical intervention such as laparotomy, cystectomy, or prolonged hospitalization. Intestinal and urinary complications were evaluated in reference to several parameters that might have an impact on their incidence (i.e., previous laparotomy, stage of disease, hypertension, positive lymph nodes, previous transurethral resection, total dose, and energy of accelerator used). Only total dose (greater than 70 Gray) was found to have a significant impact on the incidence of the urinary complications. None of these factors had a significant impact on the incidence of intestinal complications. These data from two large multi-institutional trials represent a fair estimate of the actual incidence of major intestinal and urinary complications from external beam irradiation in the management of local and locoregional adenocarcinoma of the prostate. Since the incidence of these major complications remains very low, we believe that external beam irradiation remains an excellent alternative to radical prostatectomy in the management of these patients.

Late GI and GU complications in the treatment of prostate cancer

PURPOSE

To assess the factors that predict late GI and GU morbidity in radiation treatment of the prostate.

METHODS AND MATERIALS

Seven hundred twelve consecutive prostate cancer patients treated at this institution between 1986 and 1994 (inclusive) with conformal or conventional techniques were included in the analysis. Patients had at least 3 months follow-up and received at least 65 Gy. Late GI Grade 3 morbidity was rectal bleeding (requiring three or more procedures) or proctitis. Late Grade 3 GU morbidity was cystitis or stricture. Multivariate analysis (MVA) was used to assess factors related to the complication-free survival. The factors assessed were age, occurrence of side effects > or = Grade 2 during treatment, irradiated volume parameters (use of pelvic fields, treatment of seminal vesicles to full dose or 57 Gy, and use of additional rectal shielding), dose, comorbidities, and other treatments (hormonal manipulation, TURP).

RESULTS

Acute GI and GU side effects (Grade 2 or higher) were noted in 246 and 201 patients, respectively; 67 of these patients exhibited both. GI side effects were not correlated with GU side effects acutely. Late and acute morbidities were correlated (both GI and GU). Fifteen of the 712 patients expressed Grade 3 or 4 GI injuries 3 to 32 months after the end of treatment, with a mean of 14.3 months. One hundred fifteen patients expressed Grade 2 or higher GI morbidity (mean: 13.7 months). The 43 Grade 2 or higher GU morbidities occurred significantly later (mean: 22.7 months). Central axis dose was the only independent variable significantly related to the incidence of late GI morbidity on MVA. No treatment volume parameters were significant for Grade 3. The following parameters were significantly related (by MVA) to Grade 2 GI morbidity: central axis dose, use of the increased rectal shielding, androgen deprivation therapy starting before RT. Acute and late GI morbidities were highly correlated. History of diabetes, treatment of pelvic nodes, and age less than 60 years were significantly related to acute GI side effects. The parameters significantly related to late Grade 2 or higher GU morbidity were central axis dose, androgen deprivation therapy (Zoladex or Lupron) prior to radiation therapy (RT), history of obstructive symptoms, and acute GU side effects. There were too few late Grade 3 GU morbidities to perform multivariate analysis. Acute GU side effects were highly correlated with late GU injury. The following were correlated with acute GU side effects: history of diabetes (+), treatment with conformal fields (-), TURP before RT (-), presentation with urinary obstructive symptoms.

CONCLUSION

Both late GI and GU morbidity demonstrate a dose dependence, but only the volume dependence observed is a reduction in late Grade 2-4 GI morbidity by increasing the rectal shielding in the lateral fields for the final 10 Gy. Moreover, both late GI and GU morbidity was increased in patients treated with hormone manipulation prior to RT. GI and GU injuries were correlated with their corresponding acute side effects. GI and GU complications must not be combined for analysis to determine the factors related to their occurrence.

Pretreatment and treatment factors associated with improved outcome in squamous cell carcinoma of the uterine cervix: a final report of the 1973 and 1978 patterns of care studies

The Patterns of Care Study (PCS) conducted two national surveys of patients treated in 1973 and 1978 for squamous cell cancer of the uterine cervix. In addition, a survey of patients treated in 1973 from selected large facilities was conducted to establish outcome with "optimal" radiotherapy. The large facility survey consistently reported improved outcome compared to both national average surveys when analyzed by stage and other significant pretreatment factors. That improved outcome was associated with the paracentral (PCS point A) dose and the use of intracavitary irradiation. In this study, we report the pretreatment and treatment factors associated with improved outcome in squamous cell carcinoma of the uterine cervix by analysis of the 1973 and 1978 PCS data. Pretreatment factors associated with improved pelvic control in multivariate analysis include higher Karnofsky Performance Status (KPS) (Stage I and II), older age (Stage I and II), unilateral parametrial involvement (Stage IIB), and unilateral sidewall involvement (Stage III). The only treatment factor associated with improved pelvic control in multivariate analysis is the use of intracavitary irradiation. However, a dose response for infield pelvic control was demonstrated only in Stage III cervix cancer with the highest rate of pelvic control with paracentral (PCS point A) dose greater than 8500 cGy. Multivariate analysis revealed that unilateral parametrial involvement for Stage IIB and unilateral sidewall involvement for Stage III are significant positive prognostic factors with respect to survival after treatment with radiotherapy. No FIGO substage significantly affected survival after radiotherapy. Although FIGO staging is the single most important pretreatment prognostic factor with respect to survival and infield pelvic failure, FIGO substaging deserves reappraisal and further refinement. Major complications were seen in only 9.5% of patients treated with radiotherapy and were stage but not survey related. There is a significant relationship between PCS point A dose and complications with the highest rate of complications for PCS point A dose greater than 8500 cGy. A significant relationship between lateral (external iliac lymph nodes or PCS point P) dose and major complications is also found, and doses greater than 5000 cGy are associated with a significant increase in complications. The PCS has established two sequential national benchmarks of treatment outcome for squamous cell carcinoma of the uterine cervix treated with radiotherapy with respect to survival, infield pelvic control, and complications.(ABSTRACT TRUNCATED AT 400 WORDS)

The influence of treatment time on outcome for squamous cell cancer of the uterine cervix treated with radiation: a patterns-of-care study

PURPOSE

To analyze the effect of total treatment time on infield pelvic control and survival for squamous cell carcinoma of the uterine cervix using the combined 1973 and 1978 Patterns of Care (PCS) data base.

METHODS AND MATERIALS

Eight hundred thirty-seven evaluable patients were analyzed for the effect of total treatment time on outcome. The Kaplan-Meier method was used to estimate time-to-outcome annual rates. Comparisons of time to failure were performed with the log rank test. Multivariate analysis was performed using the Cox regression analysis.

RESULTS

A highly significant decrease in survival (p = .0001) and pelvic control (p = .0001) was demonstrated as the total treatment time was increased from < 6, 6 to 7.9, 8 to 9.9, and 10+ weeks. Stage III accounted for the majority of the adverse effect from the prolongation of total treatment time. Multivariate analysis of total treatment time in addition to previously reported significant pretreatment and treatment factors from the PCS data base revealed three independent factors for infield recurrence, namely Stage I versus II versus III (p = .0001), total treatment time < 6 versus 6 to 7.9 versus 8 to 9.9 versus 10+ weeks (p = .003), and age > 50 versus < or = 50 years (p = .01). When the analysis was performed by stage to evaluate the effect of overall treatment time with respect to the extent of pelvic disease as defined by PCS, total treatment time continued to be an independent prognosticator for infield pelvic control (p = .01) and survival (p = .02) for Stage III but not Stages I and II.

CONCLUSION

This study demonstrates a significant adverse effect on survival and pelvic control with prolongation of the total radiation treatment time for Stage III squamous cell cancer of the uterine cervix in multivariate analysis. In the future design of clinical trials, limitations on total treatment time should be rigorously controlled, and the effect of variations in this important factor by altered fractionation schemes should be studied.

The effect of dose on local control of prostate cancer

Three patterns of care outcome surveys in prostate cancer totalling 1516 patients had been combined and analyzed for the effect of dose on infield recurrence. There are significant dose effects observed in the overall data (1516 patients, p = .003), Stage B cancers (725 patients, p = .004) and Stage C cancers (624 patients, p = .059). No dose effect was observed for Stage A cancers (168 patients, p = .217) within the dose range observed (5500 cGy to greater than 7000 cGy). For patients with Stage B cancer one may conclude that dose between 6000 cGy and 6999 cGy is appropriate. Patients treated to less than 6000 cGy show a highly significant increase in local failure. Patients treated to greater than 7000 cGy do not show a demonstrable improvement in local control, but do show an increase in complications. Patients with Stage C cancer appear to require dose that is equal or greater than 7000 cGy to obtain the best local control, and the potential increased morbidity of these high doses appears to be justified in this stage of the disease. Patients who have been given hormonal therapy more than 1 month prior to radiation therapy show an increase in local failure rate for all stages of cancer. This is presumed to be the selection of poor risk patients for adjuvant hormonal treatment or by referring non-responding hormone treated patients for radiation therapy. Histologic grade exerts a major influence on local failure for patients with Stage C disease (p = less than .001), identifying an important stratification point for prospective clinical trials and a sub-group for which it is important to develop strategies for improving local control. The policy of treating all stages of prostate cancer with the same dose is not supported by these data.

Preliminary report of toxicity following 3D radiation therapy for prostate cancer on 3DOG/RTOG 9406

PURPOSE

A prospective Phase I dose escalation study was conducted to determine the maximally-tolerated radiation dose in men treated with three-dimensional conformal radiation therapy (3D CRT) for localized prostate cancer. This is a preliminary report of toxicity encountered on the 3DOG/RTOG 9406 study.

METHODS AND MATERIALS

Each participating institution was required to implement data exchange with the RTOG 3D quality assurance (QA) center at Washington University in St. Louis. 3D CRT capabilities were strictly defined within the study protocol. Patients were registered according to three stratification groups: Group 1 patients had clinically organ-confined disease (T1,2) with a calculated risk of seminal vesicle invasion of < 15%. Group 2 patients had clinical T1,2 disease with risk of SV invasion > or = 15%. Group 3 (G3) patients had clinical local extension of tumor beyond the prostate capsule (T3). All patients were treated with 3D techniques with minimum doses prescribed to the planning target volume (PTV). The PTV margins were 5-10 mm around the prostate for patients in Group 1 and 5-10 mm around the prostate and SV for Group 2. After 55.8 Gy, the PTV was reduced in Group 2 patients to 5-10 mm around the prostate only. Minimum prescription dose began at 68.4 Gy (level I) and was escalated to 73.8 Gy (level II) and subsequently to 79.2 Gy (level III). This report describes the acute and late toxicity encountered in Group 1 and 2 patients treated to the first two study dose levels. Data from RTOG 7506 and 7706 allowed calculation of the expected probability of observing a > or = grade 3 late effect more than 120 days after the start of treatment. RTOG toxicity scores were used.

RESULTS

Between August 23, 1994 and July 2, 1997, 304 Group 1 and 2 cases were registered; 288 cases were analyzable for toxicity. Acute toxicity was low, with 53-54% of Group 1 patients having either no or grade 1 toxicity at dose levels I and II, respectively. Sixty-two percent of Group 2 patients had either none or grade 1 toxicity at either dose level. Few patients (0-3%) experienced a grade 3 acute bowel or bladder toxicity, and there were no grade 4 or 5 toxicities. Late toxicity was very low in all patient groups. The majority (81-85%) had either no or mild grade 1 late toxicity at dose level I and II, respectively. A single late grade 3 bladder toxicity in a Group 2 patient treated to dose level II was recorded. There were no grade 4 or 5 late effects in any patient. Compared to historical RTOG controls (studies 7506, 7706) at dose level I, no grade 3 or greater late effects were observed in Group 1 and Group 2 patients when 9.1 and 4.8 events were expected (p = 0.003 and p = 0.028), respectively. At dose level II, there were no grade 3 or greater toxicities in Group 1 patients and a single grade 3 toxicity in a Group 2 patient when 12.1 and 13.0 were expected (p = 0.0005 and p = 0.0003), respectively. Multivariate analysis demonstrated that the relative risk of developing acute bladder toxicity was 2.13 if the percentage of the bladder receiving > or = 65 Gy was more than 30% (p = 0.013) and 2.01 if patients received neoadjuvant hormonal therapy (p = 0.018). The relative risk of developing late bladder complications also increased as the percentage of the bladder receiving > or = 65 Gy increased (p = 0.026). Unexpectedly, there was a lower risk of late bladder complications as the mean dose to the bladder and prescription dose level increased. This probably reflects improvement in conformal techniques as the study matured. There was a 2.1 relative risk of developing a late bowel complication if the total rectal volume on the planning CT scan exceeded 100 cc (p = 0.019).

CONCLUSION

Tolerance to high-dose 3D CRT has been better than expected in this dose escalation trial for Stage T1,2 prostate cancer compared to low-dose RTOG historical experience. With strict quality assurance standards and review, 3D CRT can be safely studied in a co

A comparison of daily CT localization to a daily ultrasound-based system in prostate cancer

PURPOSE

Daily CT localization has been demonstrated to be a precise method of correcting radiation field placement by reducing setup and organ motion variations to facilitate dose escalation in prostate carcinoma. The purpose of this study was to evaluate the feasibility and accuracy of daily ultrasound-guided localization utilizing daily CT as a standard. The relatively simple computer-assisted ultrasound-based system is designed to be an efficient means of achieving daily accuracy.

METHODS AND MATERIALS

After five weeks of conformal external beam radiation therapy, 23 patients underwent a second CT simulation. Prostate-only fields based on this scan were created with no PTV margin. On each of the final conedown treatment days, a repeat CT simulation and isocenter comparison was performed. Ten of the above patients also underwent prostate localization with a newly developed ultrasound-based system (BAT) that is designed to facilitate patient positioning at the treatment machine. The portable system, which electronically imports the CT simulation target contours and isocenter, is situated adjacent to the treatment couch. Transverse and sagittal suprapubic ultrasound images are captured, and the system overlays the corresponding CT contours relative to the machine isocenter. The CT contours are maneuvered in three dimensions by a touch screen menu to match the ultrasound images. The system then displays the 3-D couch shifts required to produce field alignment.

RESULTS

The BAT ultrasound system produced good quality images with minimal operator training required. The localization process was completed in less than 5 min. The absolute magnitude difference between CT and ultrasound was small (A/P range 0 to 5.9 mm, mean 3 mm +/- 1.8; Lat. range 0 to 7.9 mm, mean 2.4 mm +/- 1.8; S/I range 0 to 9 mm, mean 4.6 mm +/- 2.8). Analysis confirmed a significant correlation of isocenter shifts (A/P r = 0.66, p < 0.0001; Lat. r = 0.58, p < 0.003; S/I r = 0.78, p < 0.0001) in all dimensions, and linear regression confirmed the equivalence of the two modalities.

CONCLUSIONS

Daily CT localization is a precise method to improve daily target localization in prostate carcinoma. However, it requires significant human and technical resources that limit its widespread applicability. Conversely, localization with the BAT ultrasound system is simple and expeditious by virtue of its ability to image the prostate at the treatment machine in the treatment position. Our initial evaluation revealed ultrasound targeting to be functionally equivalent to CT. This ultrasound technology is promising and warrants further investigation in more patients and at other anatomical sites.

Long-term results of infusional 5-FU, mitomycin-C and radiation as primary management of esophageal carcinoma

An analysis of the results of 90 patients with esophageal cancer treated prospectively with combined chemotherapy and radiation without surgery and with a median follow-up of 45 months is presented. Fifty-seven patients with Stage I or II disease received definitive treatment consisting of 6,000 cGy in 6 to 7 weeks and 5-FU (1,000 mg/m2/24 hr) as a continuous intravenous (IV) infusion for 96 hours, starting on days 2 and 29. Mitomycin C (10 mg/m2) was administered as a bolus injection on day 2. Thirty-three patients received palliative treatment (5,000 cGy plus above chemotherapy) for Stage III, IV, or otherwise advanced disease (extraesophageal spread, distant metastases, multiple primary tumors). Follow-up ranged from 1 month to 96 months. Overall median survival of Stage I and II patients was 18 months with 3- and 5-year actuarial survival of 29% and 18%, respectively, while the median disease specific survival was 20 months with an actuarial disease specific survival of 41% and 30% at 3 and 5 years, respectively. A multivariate analysis of sex, histology, tumor location, and tumor size on survival revealed that the effect of stage was highly significant (Stage I versus II, 73% versus 33% at 3 years, p = .01), whereas the effect of sex approached significance (females versus males, 57% versus 34% at 3 years, p = less than .1). The actuarially determined local relapse-free rate for Stage I and II patients at both 3 and 5 years was 70%. Multivariate analysis again indicated stage to be highly significant (Stage I versus II, 100% versus 60% at 3 years, p = less than .01), whereas sex approached significance (female versus male, 75% versus 66% at 3 years, p = .07). The pattern of failure may be altered with this treatment regimen from local to one dominated by distant metastases. Of 29 patients who have failed, 14 (48%) had any component of local failure, whereas 21 (72%) had a distant failure as a component of failure. The median survival of patients with Stage III or IV disease was 9 months and 7 months, respectively. Palliation in this group of patients with advanced disease was good as 77% were rendered free of dysphagia post-treatment, and 60% were without dysphagia until death with a median dysphagia-free duration of 5 months. Severe toxicities were uncommon and nearly all were transient. Eleven of 90 patients (12.2%) had severe acute toxicities, whereas only 3 patients (3.3%) developed significant late treatment-related complications requiring hospitalization for management.

Cardiovascular mortality after androgen deprivation therapy for locally advanced prostate cancer: RTOG 85-31

PURPOSE

Gonadotropin-releasing hormone (GnRH) agonists are associated with greater risk of coronary heart disease and myocardial infarction in men with prostate cancer, but little is known about potential impact on cardiovascular mortality. We assessed the relationship between GnRH agonists and cardiovascular mortality in a large randomized phase III trial of men treated with or without adjuvant goserelin after radiation therapy (RT) for locally advanced prostate cancer.

PATIENTS AND METHODS

Between 1987 and 1992, 945 men with locally advanced prostate cancer were randomly assigned to RT and adjuvant goserelin or RT alone. Fine and Gray's regression was used to evaluate treatment effect on cardiovascular mortality. Covariates included age, prevalent cardiovascular disease (CVD), hypertension, diabetes mellitus (DM), body mass index, race, Gleason score, stage, acid phosphatase level, prostatectomy history, and nodal involvement.

RESULTS

After a median follow-up of 8.1 years, there were 117 cardiovascular-related deaths but no treatment-related increase in cardiovascular mortality. At 9 years, cardiovascular mortality for men receiving adjuvant goserelin was 8.4% v 11.4% for men treated without adjuvant goserelin (Gray's P = .17). In multiple regression analyses, treatment arm was not significantly associated with increased risk of cardiovascular mortality (adjusted hazard ratio [HR] = 0.73; 95% CI, 0.47 to 1.15; P = .16; when censoring at time of salvage goserelin therapy, HR = 0.99; 95% CI, 0.58 to 1.69; P = .97). Traditional cardiac risk factors, including prevalent CVD and DM, were significantly associated with greater cardiovascular mortality.

CONCLUSION

GnRH agonists do not seem to increase cardiovascular mortality in men with locally advanced prostate cancer. Further studies are warranted to evaluate adverse effects of GnRH agonists in men with lower cancer-specific mortality.

Patterns of care outcome studies. Results of the national practice in cancer of the cervix

This report summarizes the national data collected by the Patterns of Care Study in the process and outcome of care in the treatment of carcinoma of the cervix. Substantial variation was found from a consensus of best current management, although training facilities tended to score higher than nontraining on a compliance measure. Four year national averages for control of cervical cancer are: Stage I, 87%, Stage II, 66%, Stage III, 28%. Factors relating to recurrences include failure to use intracavitary irradiation, the type of equipment, the central dose, and Karnofsky Score. The presence of complications is associated with daily dose, lateral dose and central dose, among other factors, and was shown to be unacceptably high in Stage I.

Increasing prostate-specific antigen profile following definitive radiation therapy for localized prostate cancer: clinical observations

PURPOSE

To examine the natural history of patients who have received definitive radiation therapy alone for clinically localized prostate cancer and have an increasing prostate-specific antigen (PSA) profile.

PATIENTS AND METHODS

One hundred fifty-one men with an increasing PSA profile after definitive radiotherapy were identified. The subsequent natural history of these men, including local recurrence, distant metastasis, and survival, was examined. In 119 men, posttreatment PSA doubling times (PSADT) were calculated using linear regression. Cox regression models were used to examine the effect of clinical and treatment variables on clinical failure and survival.

RESULTS

Patients with high pretreatment PSA values, high Gleason scores, and T3 tumors were more likely to develop a PSA elevation. The median calculated post-treatment PSADT was 13 months, and 95% of patients had posttreatment PSADT of less than 3 years. PSADT was correlated with tumor stage and Gleason score. Five years after PSA elevation, the estimated rate of clinical local recurrence is 26% and the estimated rate of distant metastases is 47%. Rapid PSADT (< 12 months) and a short interval from the end of treatment to PSA elevation (< 12 months) were significant independent predictors of distant metastases. The estimated rates of overall and cause-specific survival 5 years after PSA elevation are 65% and 76%, respectively. Gleason grade is the only significant independent predictor of overall and cause-specific survival after PSA elevation.

CONCLUSION

The natural history of men who have an increasing PSA profile following definitive radiotherapy is heterogeneous. In the absence of salvage therapy, at least three quarters of men will have clinical evidence of recurrent disease 5 years after a PSA elevation is detected. Men with a rapid posttreatment PSADT and a short interval from the end of treatment to an increasing PSA profile are at a very high risk of developing distant metastasis within 5 years of PSA elevation.

The Patterns of Care Outcome Study for cancer of the uterine cervix. Results of the Second National Practice Survey

This report summarizes the outcome results of the Patterns of Care Study (PCS) of cancer of the uterine cervix from 565 patients treated in 1978. The 5-year survival with no evidence of disease was: Stage I, 74%; Stage II, 56%; and Stage III, 33%. The 5-year local in-field failure rate was: Stage I, 12%, Stage II, 27%; and Stage III, 51%. Extent of parametrial involvement, unilateral versus bilateral, may be important in determining survival and local failure. The four-year actuarial survival was 58% for unilateral involvement versus 47% for bilateral (P = 0.06), and the local failure rate was 32% for unilateral versus 45% for bilateral (P less than 0.05). When analyzed by stage, patients with Stage IIb disease with unilateral parametrial involvement showed a trend toward improved survival and decreased local failure compared with those with bilateral Stage IIb cancers (P = 0.1). The use of intracavitary irradiation significantly improved survival and reduced local failures. Furthermore, the number of intracavitary applications was important. When two or more intracavitary applications were used compared with one application, local in-field failure was significantly reduced, 29% versus 17% at 4 years (P less than 0.001), and four-year survival was improved, 60% versus 73% (P = 0.01). The four-year actuarial rate of major complications depended on the stage: Stage I, 8%; Stage II, 15%; and Stage III, 13%. There was a statistically significant increase in major complications in patients undergoing laparotomy for staging versus no laparotomy 23% versus 11% at 4 years (P less than or equal to 0.01) and a trend toward increased major complications in patients who were thin or had prior abdominal surgery. This study confirmed the stage-dependent outcome of treatment of cancer of the uterine cervix with radiation and indicated that further division of Stage IIb to indicate prognostic significance of unilateral or bilateral parametrial involvement may be warranted. This study also confirmed the importance of intracavitary radiation in optimizing control established by the 1973 PCS. It further suggests that where possible, two intracavitary insertions may yield better results than one insertion.

Hypoxic prostate/muscle pO2 ratio predicts for biochemical failure in patients with prostate cancer: preliminary findings

OBJECTIVES

To investigate whether low partial pressure of oxygen (PO2) in prostate cancer (CaP) predicts for biochemical outcome after radiotherapy. We previously reported that hypoxic regions exist in human CaP.

METHODS

Custom-made Eppendorf PO2 microelectrodes were used to obtain approximately 100 PO2 readings from both pathologically involved regions of the prostate (as determined by sextant biopsies) and normal muscle (as an internal control). Fifty-seven patients with localized disease were prospectively studied; all received brachytherapy implants (48 low dose rate and 9 high dose rate) under spinal anesthesia. Nine patients had received prior hormonal therapy. Biochemical failure was defined as two consecutive rises in prostate-specific antigen level, without a return to baseline. Cox proportional hazards regression analysis was used to evaluate the influence of hypoxia on biochemical control, while adjusting for prostate-specific antigen, Gleason score, stage, implant type (low dose rate versus high dose rate), perineural invasion, hemoglobin level, use of hormonal therapy, average (mean) of the median prostate PO2, average median muscle PO2, and prostate/muscle PO2 (P/M) ratio.

RESULTS

With a median follow-up of 19 months (range 4 to 31), 9 patients developed biochemical failure. A threshold analysis of the P/M ratio demonstrated that biochemical control at 2 years differed significantly at a ratio of less than 0.05 versus 0.05 or greater (31% versus 92%, P <0.0001). However, the classic prognosticators were similar in these two groups. On multivariate analysis, the P/M ratio was the only predictor of biochemical control (P = 0.0002).

CONCLUSIONS

To our knowledge, this is the first study to correlate the degree of hypoxia in CaP with treatment outcome after radiotherapy. The P/M PO2 ratio was the strongest predictor for biochemical control on stepwise multivariate analysis. Longer follow up with more patients is planned to confirm this result.

Elective pelvic irradiation in stage A2, B carcinoma of the prostate: analysis of RTOG 77-06

From 1978 to 1983 the Radiation Therapy Oncology Group conducted a study to evaluate the role of elective pelvic lymph node irradiation in carcinoma of the prostate. Eligible patients were those with clinical Stage A2 (occult disease with more than 3 positive chips and poorly differentiated tumor) and Stage B without clinical (lymphangiogram) or biopsy evidence of lymph node involvement. The patients were randomized to receive 6.5 weeks of either prostatic bed irradiation only 6500 cGy at 180-200 cGy per treatment or pelvic node irradiation to 4500 cGy with a boost of 2000 cGy to the prostatic bed bringing the total dose to 6500 cGy. As of February, 1988, the median follow up has been 7 years and there were 445 analyzable cases who were evaluated for local control, incidence of distant metastases, ned (no evidence of disease) survival and survival. The results of the study revealed no statistically significant benefit of elective pelvic irradiation.

Cardiovascular mortality and duration of androgen deprivation for locally advanced prostate cancer: analysis of RTOG 92-02

OBJECTIVES

Gonadotropin-releasing hormone agonists (GnRHa) are associated with greater risk of coronary heart disease and myocardial infarction in men with prostate cancer, but little is known about their potential effects on cardiovascular mortality. We assessed the relationship between duration of GnRHa therapy and cardiovascular mortality in a large randomized trial of men treated with short-term versus longer-term adjuvant goserelin and radiation therapy (RT) for locally advanced prostate cancer.

METHODS

From 1992 to 1995, 1554 men with locally advanced prostate cancer (T2c-4, prostate-specific antigen [PSA] <150 ng/ml) received RT and 4 mo of goserelin and then were randomized to no additional therapy (arm 1) or 24 mo adjuvant goserelin (arm 2) in a phase 3 trial (Radiation Therapy Oncology Group [RTOG] 92-02). Cox regression analyses were performed to evaluate the relationship between treatment arm and cardiovascular mortality. Covariates included age, prevalent cardiovascular disease (CVD), hypertension, diabetes (DM), race, PSA, Gleason score, and stage.

RESULTS

After median follow-up of 8.1 yr, 185 cardiovascular-related deaths had occurred. No increase in cardiovascular mortality occurred for men receiving a longer duration of goserelin. At 5 yr, cardiovascular mortality for men receiving longer-term adjuvant goserelin was 5.9% versus 4.8% with short-term goserelin (Gray's p=0.16). In multivariate analyses, treatment arm was not significantly associated with increased risk of cardiovascular mortality (adjusted hazard ratio [HR]=1.09; 95% confidence interval [CI], 0.81-1.47; p=0.58; when censoring at time of salvage goserelin, HR=1.02, 95%CI, 0.73-1.43; p=0.9). Traditional cardiac risk factors, including age, prevalent CVD, and DM, were significantly associated with greater cardiovascular mortality.

CONCLUSIONS

Longer duration of adjuvant GnRHa therapy does not appear to increase cardiovascular mortality in men with locally advanced prostate cancer.

Diabetes mellitus: a predictor for late radiation morbidity

PURPOSE

Given the high frequency of diabetes, as well as prostate cancer in the elderly population, we sought to determine whether diabetic patients treated with three-dimensional conformal external-beam radiotherapy (3DCRT) had an increased risk of late gastrointestinal (GI) or genitourinary (GU) complications.

METHODS AND MATERIALS

Nine-hundred forty-four prostate cancer patients were treated between April 1989 and October 1996 using 3DCRT. Median patient age was 69 years (range 48-89), median center of prostate dose was 7211 cGy (range 6211-8074) and median follow-up was 36 months (range 2-99). Patients were evaluated every 6 months with digital rectal examinations, serum PSAs and symptom questionnaires. Radiation morbidity was quantified using Radiation Therapy Oncology Group (RTOG) and modified Late Effects Normal Tissue Task Force (LENT) scales. Patients with a preexisting history of either Type I or Type II diabetes mellitus were coded as diabetics.

RESULTS

One hundred twenty-one patients had diabetes (13% of total). Rates of acute morbidity did not differ between diabetics and nondiabetics; however, diabetics experienced significantly more late grade 2 GI toxicity (28% vs. 17%, p = 0.011) and late grade 2 GU toxicity (14% vs. 6%, p = 0.001). There was a trend toward increased late grade 3 and 4 GI complications in diabetics, but not for late grade 3 and 4 GU complications; however, the total number of recorded events for these categories was small. Examining the onset of late toxicity, diabetics developed GU complications earlier than nondiabetics (median: 10 months vs. 24 months, p = 0.02). Considering age, dose, rectal blocking, field size, and history of diabetes in a stepwise multivariate regression model for late grade 2 GI toxicity, dose (p = 0.0001), diabetes (p = 0.0110), and rectal blocking (p = 0.0163) emerged independently predictive for complications. For late grade 2 GU toxicity, only the presence of diabetes remained independently significant (p = 0.0014).

CONCLUSION

Diabetes mellitus is common in the elderly prostate cancer population. Diabetics are at a significant risk for the development of late grade 2 GI and GU complications after external-beam radiotherapy for prostate cancer. While diabetes, radiation dose, and rectal blocking predict for late GI complications, only the presence of diabetes influences late GU morbidity. Physicians may consider treatment modifications for diabetic patients, particularly those patients wishing to enter dose-escalation studies. Further study of the relationship between diabetes and late radiation complications is needed.

Lateral rectal shielding reduces late rectal morbidity following high dose three-dimensional conformal radiation therapy for clinically localized prostate cancer: further evidence for a significant dose effect

PURPOSE

Using conventional treatment methods for the treatment of clinically localized prostate cancer central axis doses must be limited to 65-70 Gray (Gy) to prevent significant damage to nearby normal tissues. A fundamental hypothesis of three-dimensional conformal radiation therapy (3DCRT) is that, by defining the target organ(s) accurately in three dimensions, it is possible to deliver higher doses to the target without a significant increase in normal tissue complications. This study examines whether this hypothesis holds true and whether a simple modification of treatment technique can reduce the incidence of late rectal morbidity in patients with prostate cancer treated with 3DCRT to minimum planning target volume (PTV) doses of 71-75 Gy.

METHODS AND MATERIALS

The 257 patients with clinically localized prostate cancer who completed 3DCRT by December 31, 1993 and received a minimum PTV dose of 71-75 Gy are included in this report. The median follow-up time was 22 months (range: 4-67 months); 98% of patients had follow-up of longer than 12 months. The calculated dose at the center of the prostate was < 74 Gy in 19 patients, 74-76 Gy in 206 patients, and > 76 Gy in 32 patients. Late rectal morbidity was graded according to the Late Effects Normal Tissue (LENT) scoring system. Eighty-eight consecutive patients were treated with a rectal block added to the lateral fields. In these patients the posterior margin from the prostate to the block edge was reduced from the standard 15 to 5 mm for the final 10 Gy, which reduced the dose to portions of the anterior rectal wall by approximately 4-5 Gy. Estimates of rates for rectal morbidity were determined by Kaplan-Meier actuarial analysis. Differences in morbidity percentages were evaluated by the Pearson chi-square test.

RESULTS

Grade 2-3 rectal morbidity developed in 46 out of 257 patients (18%) and in the majority of cases consisted of rectal bleeding. No patient has developed Grade 4 or 5 rectal morbidity. The actuarial rate of Grade 2-3 morbidity is 23% at 24 months and the median time to the development of Grade 2-3 complications is 15 months. A statistically significant dose effect is evident. The incidence of Grade 2-3 rectal morbidity increased as the dose at the center of the prostate increased (p = 0.05). In patients receiving minimum PTV doses of < or = 76 Gy the use of a rectal block significantly reduced the incidence of Grade 2-3 toxicity; 6 out of 88 (7%) with a block vs. 30 out of 137 (22%) without a block, (p = 0.003).

CONCLUSION

The incidence of late rectal morbidity with 3DCRT to minimum PTV doses of 71-75 Gy is acceptable and to date no Grade 4-5 rectal morbidities have been observed. In our experience, higher doses to the center of the prostate are associated with an increased likelihood of developing Grade 2-3 rectal morbidity but treatment techniques that reduce the total dose to the anterior rectal wall have reduced the incidence of late rectal morbidity. If clinical studies indicate improved tumor control with minimum PTV doses above 71 Gy, then dose escalation above 76 Gy to the center of the prostate should be pursued cautiously with treatment techniques that limit the total dose to the anterior rectal wall.

Patterns of care outcome studies: results of the national practice in adenocarcinoma of the prostate

The Patterns of Care Study reviewed the processes and outcome of 682 patients with carcinoma of the prostate treated with radiation therapy from 1973-1976. The study and patient sampling were designed to reflect a valid representation of how prostate cancer is treated by radiation oncologists in the United States. The outcome results represent national benchmarks. The three year actuarial survival was 91% for Stage A, 88% for Stage B, and 76% for Stage C. The three year relapse free survival rate was 85% for Stage A, 77% for Stage B, and 59% for Stage C. The infield recurrence rates were: Stage A--4%, Stage B--9%, and Stage C--20%. Stage, grade, elevated serum acid phosphatase, Karnofsky performance status, previous hormonal therapy, age, and prior transurethral resection were identified by multivariate regression analysis to be important independent prognostic variables. Local control was related to the dose of the primary site, paraprostatic region, and pelvic sidewall. Local control was significantly improved if the facility's best treatment equipment was a linear accelerator. Major complications occurred in 9% of patients with Stage A, 2% of Stage B, and 6% with Stage C disease. Complications were related to dose and treatment technique. The Patterns of Care Process Survey identified that only 60% of patients surveyed had the necessary pretreatment evaluation studies required for best current management of adenocarcinoma of the prostate. Variance occurred within each stratum of facilities sampled. Strict attention to the details of evaluation of therapy will help to enhance the delivery of optimal radiation therapy in the management of patients with carcinoma of the prostate.