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

[Radiotherapy of stage T1-T2 M0 prostatic adenocarcinoma. Analysis of the carcinologic results of a multicenter study of 610 patients. Groupe Radiothérapie de la Commission de Coopération Médicale Intercentres (CCMI)]

PURPOSE

Retrospective analysis of the results of radiotherapy in localized prostatic adenocarcinoma. Complications were excluded.

PATIENTS AND METHODS

Six-hundred-and-ten T1-T2 adenocarcinomas of the prostate were treated with continuous courses of external beam radiation therapy in 19 participating Institutes between January 1983 and January 1988. The mean follow-up was 10.4 years; the mean age of patients at the beginning of radiotherapy was 68.5 years.

RESULTS

A 10-year, local control had been achieved in 86% of T1-T2 (81.4% for T2). The 5- and 10-year metastatic relapse rates were 25.3% and 30% (29% and 38.1% for T2), respectively. At 10 years, 62.4% of T1-T2 were recurrence-free; overall survival rate was 45.8% and cause-specific survival rate was 70.5%; 29.9% of T1-T2 patients were alive and disease-free. T category (TNM), pathologic grade, pelvic lymph node status, local tumor control, and obstructive ureteral symptoms were correlated with survival. The influence of pelvic nodes radiation, dose, overall treatment time, previous endocrine treatment, and transuretral resection was not significant for disease-free survival (alive and disease-free) and other endpoints.

CONCLUSION

There was no difference between the French series (1975-1982 and 1983-1988). The results of the literature are comparable to ours. As far as prognostic factors are concerned, this report provides evidence that the explainable variables which influence survival depend on the tumor and patient status.

Combined orchiectomy and external radiotherapy versus radiotherapy alone for nonmetastatic prostate cancer with or without pelvic lymph node involvement: a prospective randomized study

PURPOSE

We compare the combination of orchiectomy and radiotherapy to radiotherapy alone as treatment for pelvic confined prostate cancer, that is T1-4, pN0-3, M0 (TNM classification).

MATERIALS AND METHODS

In this prospective study 91 patients with clinically localized prostate cancer were, after surgical lymph node staging, randomized to receive definitive external beam radiotherapy (46) or combined orchiectomy and radiotherapy (45). Patients treated with radiotherapy alone had androgen ablation at clinical disease progression. The effects on progression-free, disease specific and overall survival rates were calculated.

RESULTS

After a median followup of 9.3 years (range 6.0 to 11.4) clinical progression was seen in 61% of the radiotherapy only patients (group 1) and in 31% of the combined treatment patients (group 2) (p = 0.005). The mortality was 61 and 38% (p = 0.02), and cause specific mortality was 44 and 27%, respectively (p = 0.06), in groups 1 and 2. The differences in favor of combined treatment were mainly caused by lymph node positive tumors. For node negative tumors there was no significant difference in survival rates.

CONCLUSIONS

The progression-free, disease specific and overall survival rates for patients with prostate cancer and pelvic lymph node involvement are significantly better after combined androgen ablation and radiotherapy than after radiotherapy alone. These results strongly suggest that early androgen deprivation is better than deferred endocrine treatment for these patients.

[Indications and results of exclusive radiotherapy in early prostatic adenocarcinoma]

Prostate adenocarcinoma incidence are rising rapidly, especially in early stages. Even if some of these carcinomas may be latent or slow growing either spontaneously or under hormonal therapy, most patients 75 years old or less presenting a localized tumor, T1b-c, T2, T3, N0, M0, whatever the grading, will require treatment with curative intent: radical prostatectomy, external beam radiation therapy (ERT) and/or brachytherapy. After ERT limited to the prostate or including seminal vesicles and/or pelvic lymph nodes, the overall survival and the survival without clinical evolution at 5, 10 and 15 years are good. However survival rates without biochemical evolution are about 30% lower and 70% or less at 5 years for the more favorable group (T < or = T2a and Gleason < 7 and PSA < 10 ng/mL). Brachytherapy alone yields good results for the same favorable group. In the unfavorable group (T > or = 2c and Gleason > or = 7 and PSA > or = 20 ng/mL), adjuvant hormonal therapy improves survival. Conformal radiation therapy allows an increase in dose to the tumor by about 15% without increasing complications. It can increase the biological remission rate in the intermediate group (T < or = 2a or Gleason > or = 7 or PSA > or = 20 ng/mL).

[Locally advanced prostate carcinoma (T2b-T4 N0) without and with clinical evidence of local progression (Tx N+) with lymphatic metastasis. Is radiotherapy for pelvic lymphatic metastasis indicated or not?]

BACKGROUND

There is a greater controversy regarding the indication of radiotherapy of the pelvic lymphatics in patients with suspected lymph node metastases in locally advanced prostate cancer (T2b-4 N0) on the one hand and in patients with pathologically proven lymph node metastases in locoregional advanced prostate cancer (Tx pN+) on the other hand following definitive radiotherapy and radical prostatectomy. This paper investigates the possible indications for radiotherapy of the pelvic lymphatics in the light of data from the literature.

PATIENTS AND METHODS

Because data from several retrospective studies concerning radiotherapy of the pelvic lymphatics indicated a better outcome, the RTOG conducted 2 prospective randomised studies (RTOG 75-06, 77-06) to address these questions. However, the results of these studies showed no better survival or cause specific survival for patients treated for the paraaortal or pelvic lymphatics and therefore, radiotherapy of the pelvic lymphatics was no more advocated. A reanalysis showed several problems of the study design and it was concluded that the studies couldn't prove the question of elective radiotherapy of the pelvic lymphatics. In RTOG 77-06 patients with T1b/T2 tumors were investigated. Therefore, there is no prospective study investigating the elective radiotherapy in patients with T3-tumors, who are at high risk of pelvic lymph node metastases.

RESULTS

Today there is no indication for treating the paraaortal lymphatics in patients with locoregional advanced prostate cancer. Many radiotherapists perform the elective radiotherapy of pelvic lymphatics when the risk of metastases is above 15 to 20% because retrospective data indicate a better outcome. On the other hand, many others don't treat them because RTOG 75-06 and 77-06 didn't demonstrate a better outcome. Laparoscopic lymphadenectomy with low morbidity seems to be helpful as in pN0 patients radiotherapy is not necessary. Where performing laparoscopic pelvine lymphadenectomy is impossible the probability of the frequency of lymph node metastases can be estimated using the clinical tumor stage, the Gleason-score and the pretherapeutic PSA. In case of proven metastases (pN+) some retrospective data indicate that patients with micrometastasis could profit from aggressive treatment. In case of proven metastases and extirpation by lymphadenectomy it seems that patients with hormonal therapy and radiotherapy have a longer tumor-free interval. However, there are no data from randomized trials.

CONCLUSIONS

Every radiotherapist has to make his own decision for radiotherapy of the pelvic lymphatics as there is no standard treatment. Two randomised studies are open and recruiting patients. These are one study of the ARO, investigating patients with histologically proven lymph node metastases and one study of the RTOG (RTOG 9413), investigating patients with an estimated risk of lymph node metastases > 15%. In case of radiotherapy of the pelvic lymphatics a dose of 45 Gy for suspected metastases and 50.4 Gy for proven metastases is recommended.

Impact of surgical staging in evaluating the radiotherapeutic outcome in RTOG #77-06, a phase III study for T1BN0M0 (A2) and T2N0M0 (B) prostate carcinoma

PURPOSE

To evaluate survival and time to metastatic disease in patients treated for localized prostatic carcinoma in a Phase III radiotherapy (RT) protocol, Radiation Therapy Oncology Group (RTOG) 77-06. Patients with T18N0M0 (A2) or T2N0M0 (B) disease after lymphangiogram (LAG) or staging laparotomy (SL) were randomized between prophylactic radiation to the pelvic lymph nodes and prostatic bed vs. prostatic bed alone. The outcome of both treatment arms, as well as a comparison of the LAG group, to that of the SL group, are updated.

METHODS AND MATERIALS

A total of 449 eligible males were entered into RTOG protocol 7706 between 1978 and 1983. Lymph node staging was mandatory but at the physician's discretion; 117 (26%) patients had SL, while 332 (74%) had LAG. Follow-up was a median of 12 years and a maximum of 16 years. For those randomized to receive prophylactic pelvic lymph nodal irradiation, 45 Gy of megavoltage RT was delivered via multiple portals in 4.5-5 weeks, while all patients received 65 Gy in 6.5-8 weeks to the prostatic bed.

RESULTS

There was no significant difference in survival whether treatment was administered to the prostate or prostate and pelvic lymph nodes. The SL group had greater 12-year survival than the LAG group (48% vs. 38%, p = 0.02). Disease-free survival was statistically significant, with 38% for the SL group vs. 26% for the LAG group (p = 0.003). Bone metastasis was less common in the SL group (14%) than the LAG group (27%) (p = 0.003).

CONCLUSION

At 12-year median follow-up, there still was no survival difference in those patients treated prophylactically to the pelvic nodes and prostatic bed vs. the prostatic bed alone. Those patients not surgically staged with only LAG for lymph node evaluation were less accurately staged, as reflected by a statistically significant reduced survival and earlier metastases.

The location of the prostatic apex on retrograde urethrography and its relationship to the bottom of the ischial tuberosities

To determine the proportion of patients undertreated if the inferior border of the prostate field is set at the bottom of the ischial tuberosities, we reviewed the ports of 80 patients with prostate cancer who had retrograde urethrography as part of simulation for radiation therapy. For the 75 evaluable urethrograms, the mean distance from the top of the urethrogram cone to the bottom of ischial tuberosities was 1.38 cm (range, -0.48-2.90 cm). A comparison of the inferior border defined by the bottom of the ischial tuberosities and retrograde urethrography showed that 47 of 75 (62.7%) patients would have been undertreated if a margin of 1.5 cm was employed, and the prostatic apex was thought to be directly above the urethrogram cone. If the apex was thought to be 1 cm above the cone, six of 75 (8.0%) patients would have been undertreated, using a margin of 1.5 cm. Although previously published reports have established that using the bottom of the ischial tuberosities as the inferior border of the prostate field results in 10-45% undertreatment, our findings, when adjusted for the variability of prostatic apex location and margin of normal tissue employed, indicate that only 8% may actually be undertreated.

Enhancement of prostate tumor volume definition with intravesical contrast: a three-dimensional dosimetric evaluation

PURPOSE

To assess the impact of intravesical contrast during computed tomography (CT) simulation on prostate tumor volume definition and dose distribution.

METHODS AND MATERIALS

Sixteen patients with localized adenocarcinoma of the prostate underwent CT-based virtual simulation in preparation for definitive radiotherapy. Patients were immobilized with a foam cradle and an initial CT was performed after oral but without intravesical contrast (noncontrast scan). A second scan was performed following administration of intravesical contrast (contrast scan). Beam apertures were designed on the noncontrast scans and digitized into the contrast scan file. Beam apertures were also designed on the contrast scans. Isodose plans were generated for several beam apertures and arrangements.

RESULTS

There was enhanced visualization of the prostate at the cephalad portion of the field for 15 of the 16 cases. The mean differences between the noncontrast and contrast volumes was significant (p = 0.0001). The mean percent underdosage to the prostate ranged from 3.9% to 18.6%, depending upon the target volume and beam arrangement.

CONCLUSION

This study demonstrates the necessity of using intravesical contrast for defining the location of the prostate during CT simulation. The underestimation of the extent of the prostate when omitting intravesical contrast leads to significant underdosage. The value of intravesical contrast is most evident when small (prostate only) conformal fields are used.

Bladder carcinoma and other second malignancies after radiotherapy for prostate carcinoma

BACKGROUND

Radiation therapy (RT) to the pelvis has been associated with an increased risk of bladder carcinoma, as well as other malignancies. However, no controlled studies have previously explored the risk of second malignancies after RT for prostate carcinoma.

METHODS

A retrospective cohort study was conducted utilizing data from the Surveillance, Epidemiology, and End Results Program (SEER) of the U. S. National Cancer Institute from 1973-1990. The standardized incidence ratio (SIR), adjusted for age, was calculated as an estimate of the relative risk (RR) of developing a second malignancy after prostate carcinoma for radiated and nonradiated prostate carcinoma patients separately.

RESULTS

The cohort was comprised of 34,889 prostate carcinoma patients who had undergone RT, and 106,872 who had not. After 8 years, the risk of bladder carcinoma was elevated for the RT group (RR 1.5; 95% confidence interval [CI], 1.1-2.0) but not for the non-RT group (RR 1.0; 95% CI, 0.7-1.2). There was an elevated risk of bladder carcinoma for the RT group at 5-8 years as well (RR 1.3; 95% CI, 1.0-1.7). No elevations in risk were observed for rectal carcinoma, acute nonlymphocytic leukemia, or chronic lymphocytic leukemia for either RT patients or non-RT patients.

CONCLUSIONS

The risk of bladder carcinoma is elevated several years after RT for prostate carcinoma, but this elevation is not dramatic. There is no increased risk of rectal carcinoma or leukemia after this type of radiation exposure.

Nonrandomized evaluation of pelvic lymph node irradiation in localized carcinoma of the prostate

PURPOSE

A great deal of controversy exists regarding the potential benefit of pelvic lymph node irradiation compared with treatment to the prostate only in patients with localized prostate cancer. Despite numerous reports, including a randomized study, this issue has not been completely elucidated.

METHODS AND MATERIALS

A total of 963 patients with histologically proven localized adenocarcinoma of the prostate treated with definitive radiation therapy alone were analyzed. Median follow-up was 6.5 years (minimum: 2 years, maximum: 22 years). Pelvic lymph nodes received 40 to 55 Gy with anteroposterior/posteroanterior and sometimes lateral stationary portals in 1.8 Gy daily fractions; an additional dose was delivered to the prostate with 120 degrees bilateral are rotation to complete doses of 65 to 68 Gy for Stage A2 and B tumors and 68 to 71 Gy for Stage C tumors. The same total doses were delivered with smaller fields when the prostate only was treated.

RESULTS

In Stage A2 (T1b,c) the 10-year clinical pelvic failure rate was 16% regardless of the volume irradiated or tumor differentiation. With Stage B (T2) well- or moderately differentiated tumors, the 10-year pelvic failure rates were 22% when pelvic lymph nodes were irradiated and 32% when prostate only was irradiated (p = 0.41). With Stage A2 (T1b,c) and B (T2) poorly differentiated tumors, the 10-year pelvic failure rates were 32% and 7%, respectively (p = 0.72). With clinical stage C (T3) well-differentiated tumors treated with 50 to 55 Gy to pelvic lymph nodes, the pelvic failure rate was 22% compared with 37% in those receiving 40 to 45 Gy (p < or = 0.07). A significant reduction in pelvic failures was noted with Stage C poorly differentiated tumors when the pelvic lymph nodes received doses higher than 50 Gy (23%) compared with lower doses (46%) (p < or = 0.01). Volume or doses of irradiation did not influence incidence of distant metastases in any stage or tumor differentiation group. Disease-free survival did not correlate with volume treated in any clinical stage or tumor differentiation group. In 317 patients on whom pretreatment prostate-specific antigen levels were available, there is a suggestion that those treated to the pelvic lymph nodes had a higher chemical disease-free survival than those receiving prostate irradiation only. Follow-up is short, and differences are not statistically significant in any of the groups. Morbidity of therapy was slightly higher in patients treated to the pelvic lymph nodes, but in Stages A2 (T1b,c) and B (T2) differences are not statistically significant (4 to 6%). Stage C patients treated to the pelvic lymph nodes with 50 Gy had a 12% incidence of Grade 2 rectosigmoid morbidity compared with 6% in those treated with 40 Gy (p = 0.26).

CONCLUSIONS

In this retrospective analysis, pelvic lymph node irradiation did not influence local/pelvic tumor control, incidence of distant metastases, or disease-free survival in patients with clinical Stage A2 (T1b,c) or B (T2) localized carcinoma of the prostate. In patients with Stage C (T3) disease, irradiation of the pelvic lymph nodes with doses of 50 to 55 Gy resulted in a lower incidence of pelvic recurrences and improved disease-free survival. Morbidity of therapy was acceptable, although patients with Stage C disease had a somewhat higher incidence of Grade 2 rectosigmoid morbidity. Pelvic lymph node irradiation is being elucidated in properly designed prospective, randomized protocols.

Prostate specific antigen findings and biopsy results following interactive ultrasound guided transperineal brachytherapy for early stage prostate carcinoma

BACKGROUND

Interactive, transrectal, ultrasound-guided transperineal implantation is a new technique for performing permanent brachytherapy implants of the prostate. Prostate specific antigen (PSA) findings, biopsy results, and morbidity are examined to demonstrate its efficacy and safety in treating early stage prostate carcinoma.

METHODS

Ninety-seven patients underwent permanent implants for classifications T1 to T2 adenocarcinoma of the prostate gland with a median follow-up of 18 months (range: 6-51 months). Seventy-nine patients had negative laparoscopic pelvic lymph node dissections prior to implantation. Patients with positive lymph nodes were not implanted. The radioactive isotope used was I-125 in 71 patients and Pd-103 in 26 patients.

RESULTS

PSA failure was defined as two consecutive increases in PSA above the nadir level. The actuarial freedom from PSA failure (FFPF) at 2 years was 76% for the entire group. Stage significantly affected FFPF. Patients classified as T1b to T2a (35) had a FFPF of 91% at 2 years compared with 68.5% for patients classified as T2b to T2c (62) (P = 0.04). The pre-treatment PSA also significantly affected FFPF. Patients with PSA values of < or = 10 ng/mL (44) had a FFPF of 83% at 2 years. A similar rate of 82% was found in patients with PSA values of 10.1 to 20 ng/mL (29). Patients with PSA values > 20 ng/mL (24) had a significantly poorer FFPF at 2 years of 58% (P = 0.02). The PSA values of patients free from a PSA failure (82) ranged from 0.1 to 12.9 ng/mL with a median of 0.8 ng/mL. Transrectal prostate biopsies were performed 18 to 36 months posttreatment in 39 patients. Negative biopsies were found in 74% (29/39) of cases. The procedure was associated with an actuarial preservation of erectile function rate and sexual potency at 2 years of 96% and 79%, respectively. There were no cases of urinary incontinence or radiation cystitis. Associated morbidity included urinary retention requiring catheterization in 4% of the patients, outlet obstruction requiring a transurethral resection of the prostate in 2% and Grade 2 rectal complications in 1%.

CONCLUSIONS

Interactive, ultrasound-guided transperineal brachytherapy results in a low PSA failure rate, high negative biopsy rate, and is associated with low morbidity and preservation of erectile function.

Sexual potency following interactive ultrasound-guided brachytherapy for prostate cancer

PURPOSE

The effect of a therapeutic modality on sexual potency is often an important consideration for patients choosing a treatment for prostate cancer. We prospectively assessed patients' penile erectile function before and following interactive ultrasound-guided transperineal permanent radioactive seed implantation to determine its effect on sexual function.

METHODS AND MATERIALS

Eighty-nine patients underwent permanent radioactive seed implantation from June 1990 to April 1994 for localized prostate cancer (T1-T2) and were followed for a median of 15 months (1.5-52 months). 125I seeds were implanted in 73 patients with a combined Gleason grade of 2-6, and 103Pd seeds were implanted in 16 patients with higher grade lesions. The sexual potency of these patients was assessed prior to, at 3 and 6 months, and every 6 months after implantation. Erectile function was graded using a numerical score of 0 to 3 (0 = impotent (no erections), 1 = ability to have erections but insufficient for vaginal penetration, 2 = erectile function sufficient for vaginal penetration but suboptimal, 3 = normal erectile function). The pretreatment potency scores were as follows: 0 in 24 patients, 1 in 6 patients, 2 in 22 patients, and 3 in 37 patients.

RESULTS

The actuarial impotency rates (score = 0) following implantation for those patients possessing some degree of erectile function prior to implantation (65 patients) were 2.5% at 1 year and 6% at 2 years. The actuarial decrease in sexual function rates (a drop in score of at least one point) were 29% at 1 year and 39% at 2 years. Only two patients became impotent following treatment and this occurred at 1 year and 16 months. The time period for a decrease in erectile function to occur ranged from 1.8 months to 32.7 months, with a median of 6.8 months. Patients with higher grade tumors showed a greater decrease in potency score compared to patients with lower grade tumors.

CONCLUSION

Interactive ultrasound-guided transperineal brachytherapy for the treatment of localized prostate cancer is associated with preservation of erectile function in the vast majority of patients, although a minor decrease in potency is not uncommon.

Prostate-specific antigen for pretreatment prediction and posttreatment evaluation of outcome after definitive irradiation for prostate cancer

PURPOSE

This study was undertaken to assess the predictive value of pretreatment prostate-specific antigen (PSA) and the difference between clinical and PSA disease-free status in patients with long-term follow-up after irradiation for prostatic carcinoma. Comparison of the distribution of prognostic factors between surgical and radiation series was also made.

METHODS AND MATERIALS

From 1975-1989, 652 patients with clinical Stage A2-C prostatic adenocarcinoma were definitively irradiated using external beam therapy. One hundred and fifty patients with banked serum and up to 14 years follow-up have pretreatment PSA levels and 355 patients with up to 17 years follow-up have posttreatment values. Treatment failure was analyzed by tumor stage, grade, and four pretreatment PSA categories. Disease-progression was evaluated by clinical and biochemical (PSA) endpoints. Prognostic factors were compared to two surgical series.

RESULTS

A significant difference was seen in clinical and PSA disease-free (PSA < or = 4.0 ng/ml) status based on tumor grade, stage, and pretreatment PSA category. Although the expected clinical outcome has been well-documented previously, results based on posttreatment PSA levels show 5-year disease-free survivals reduced by 10-16% and 10-year survivals lessened by 15-39% depending upon the particular tumor grade and stage. The earlier stage, lower grade tumors showed the largest difference between clinical and biochemical recurrence rates at the longest interval from treatment. Even more notable were the differences in the clinical and PSA disease-free rates based on the pretreatment PSA level. Comparing the irradiated patients to two surgical series showed that the former had a larger percentage of more advanced stage tumors with more unfavorable PSA levels as compared to prostatectomy patients.

CONCLUSION

With long-term follow-up, the pretreatment PSA level continues to be a powerful predictor of clinical and biochemical outcome in patients irradiated for apparently localized prostate cancer. Differences between clinical and PSA outcome can be considerable, but oftentimes clinically insignificant. The distribution of prognostic factors between radiation and prostatectomy series seems to favor the latter.

Primary radiation therapy in the treatment of localized prostatic cancer

Prostatic carcinoma is one of the leading causes of male cancer deaths. However, the routine diagnostic and therapeutic strategies have not yet been established. Although the outcome of surgical and radiotherapeutical approaches has frequently been reported to be comparable, the profile of side effects is different. This could offer the basis for selecting the treatment of choice in individual cases. During the last decade the radiotherapeutical technique has markedly improved, in part due to the achievements in the field of computer assisted tomography planning and conformal technique; the outcome of side-effects has decreased with concurrent increase in the rate of local control. The prescribing, recording and reporting of irradiation have also recently developed, as well as the staging of the disease. Therefore we consider it timely to review progress in this subject and to emphasize the role of radiotherapy in the treatment of localized prostatic cancer.

Influence of radiotherapy on node-positive prostate cancer treated with androgen ablation

PURPOSE

Patients with node-positive prostate cancer that is regionally localized (T1-4, N1-3, M0) have a relatively poor prognosis when a single-treatment modality such as radical surgery, definitive radiotherapy, or androgen ablation is used. While promising results using radical surgery and androgen ablation have been reported, there are no data to support an analogous approach using local radiotherapy and androgen ablation. In this retrospective review, the outcome after local radiotherapy and early androgen ablation (XRT/HORM) was compared to early androgen ablation alone (HORM).

METHODS AND MATERIALS

Between 1984 and 1992 there were 181 patients treated with HORM and 27 patients treated with XRT/HORM at the University of Texas M. D. Anderson Cancer Center. The nodal status of all patients was established pathologically by lymph node dissection, which was terminated after frozen section confirmation of involvement. In the majority of cases androgen ablation was by orchiectomy. The median dose to the prostate in XRT/HORM group was 66 Gy. The median follow-up was 45 months; 49 months for the HORM group and 25 months for the XRT/HORM group.

RESULTS

The distribution of prognostic factors between the HORM and XRT/HORM groups was similar, with the exception of tumor grade. There was a significantly larger proportion of high grade tumors in the HORM group. In terms of actuarial disease outcome, at 4 years the results of patients in the HORM group were significantly worse, including a rising prostate specific antigen (PSA) of 53%, any disease progression of 32%, a rising PSA or disease progression of 55%, and local progression of 22%. None of the patients in the XRT/HORM group failed biochemically or clinically. To determine the impact of grade on these findings, the analyses were repeated, using only those with grade 2 tumors. A similar pattern was evidenced with significantly worse actuarial outcome at 4 years for the HORM group using the endpoints of a rising PSA (46%), any disease progression (24%), and a rising PSA or disease progression (47%).

CONCLUSION

Node-positive prostate cancer patients with regionally localized disease fared significantly better when combined local radiotherapy and early androgen ablation were used, as compared to early androgen ablation alone. Although the number of patients in the XRT/HORM group was small and follow-up was short, the combined treatment had a dramatic effect on disease outcome and, therefore, a larger prospective randomized trial is warranted.

Radiotherapy of prostate cancer: established results and new developments

Radical radiotherapy has been established as an effective modality for eradicating localised prostate cancer. No satisfactory comparisons have been made with patients treated by total prostatectomy, but in surgically staged patients with negative lymph nodes survival after radiotherapy exceeds that of an aged matched population, cancer deaths occurring in only 6-15% of patients and 85% remaining free of local recurrence after 10 years. Results are predictably less satisfactory in surgically unstaged cases and for more advanced localised presentations. Nevertheless, radical radiotherapy achieves local control of disease in the majority of patients. Improved local control may be obtained by increasing radiation dose but at the expense of increased radiation-induced side-effects. Conformal radiotherapy and combined modality treatment with the neoadjuvant or adjuvant androgen deprivation show considerable promise as novel methods to improve the therapeutic ratio, and prospective randomised studies are underway to test these approaches.

Early prostate cancer: the national results of radiation treatment from the Patterns of Care and Radiation Therapy Oncology Group studies with prospects for improvement with conformal radiation and adjuvant androgen deprivation

Long-term outcome of the Patterns of Care Study and the Radiation Therapy Oncology Group are used to demonstrate the national average results of treating early prostate cancer in the United States. A group of patients with stage T1B2 disease and pathologically negative lymph nodes showed excellent 10-year survival rates and freedom from clinical evidence of disease, while prostate specific antigen (PSA) correlations in 10-year survivors indicate that 88% were clinically free of cancer and had a PSA level of less than 4.0 mg./nl., and 65% had a PSA level of less than 1.5 ng./ml. The latter group represented clinical and biochemical cures. The improvement noted in outcome of locally advanced prostate cancer treatment by Radiation Therapy Oncology Group prospective trials combining androgen deprivation and radiation therapy is presented. These trials will be extended to the poor prognosis group with stage T1,2 disease. The advantages of conformal therapy in acute and late morbidity are illustrated with preliminary evidence of improved PSA response as a result of improved technique and higher dose associated with conformal 3-dimensional treatment.

Indications for and the significance of seminal vesicle irradiation during 3D conformal radiotherapy for localized prostate cancer

PURPOSE

To evaluate the use of pretreatment prostate specific antigen, Gleason score, and clinical stage as predictors of the risk of seminal vesicle involvement in patients with clinically localized prostatic cancer, and to determine the impact of excluding the seminal vesicles on the dose received by surrounding normal tissues.

METHODS AND MATERIALS

An empirically derived equation combining the preoperative prostate specific antigen and Gleason score was applied to 188 patients treated with radical prostatectomy, for whom pathologic evaluation of the seminal vesicles was available. High and low risk groups for seminal vesicle involvement were defined using this equation. The observed risks of seminal vesicle involvement was compared to the predicted risk using the preoperative prostate specific antigen, Gleason score or clinical stage alone or using the empirical equation. Dose-volume histograms for five patients treated using six-field conformal radiotherapy were compared including and excluding the seminal vesicles.

RESULTS

Using the empirically derived equation, a low risk group of 109 patients was identified with a calculated risk of seminal vesicle involvement of < or = 13% and an observed incidence of 7.3%. Among the high risk group of 79 patients, which included all patients with a calculated risk > 13%, 37% had seminal vesicle involvement (p < 0.001 low vs. high risk). Twenty percent of the rectal volume received on average above 86% of the total dose for the five plans which included the seminal vesicles compared to 68% for the five plans excluding the seminal vesicles. The doses to 40% of the rectal volume were 64% and 37% if the seminal vesicles were included and excluded, respectively. The dose to the bladder and femoral heads was also decreased but to a lesser extent.

CONCLUSION

The empirical formula predicts risk of seminal vesicle involvement with a higher degree of significance for a larger number of patients than either Gleason score, clinical stage, or prostate specific antigen alone. Based on an analysis of our first 100 patients treated with definitive conformal therapy alone, approximately 47% of those patients could have been treated excluding the seminal vesicles. Excluding the seminal vesicles may allow us to go to a higher total dose with less rectal toxicity.

Location of the prostatic apex and its relationship to the ischial tuberosities

PURPOSE

Although modern computerized tomography scans have revolutionized the three-dimensional treatment planning for external beam radiation therapy for prostate cancer, the prostate apex is often difficult to precisely define. Some institutions routinely use the ischial tuberosities to define the lower border of external beam fields for prostate cancer, while others recommend a retrograde urethrogram. This study was undertaken to estimate the accuracy of using the bottom of the ischial tuberosities to define the lower border of the external beam fields for Stages T1, T2, and T3 prostate cancer.

METHODS AND MATERIALS

The anatomic location of the apex of the prostate was determined in 153 implant patients either by direct surgical exposure of the prostate (133 patients) or by using transrectal ultrasound (20 patients). The prostate apex position relative to the ischial tuberosities was determined and plotted on a schematic of the bony pelvic structures drawn to scale.

RESULTS

There was excellent agreement in the estimate of the location of the prostate apex between the two methods (surgery vs. ultrasound) used. The prostate apex was located above the ischial tuberosities in 152 of the 153 patients studied (99.3%). Seven of the 153 patients (4.6%) had a prostate apex which was less than 1.5 cm above the ischial tuberosities and 3 of the 153 patients (2%) had an apex-tuberosity distance of less than 1 cm.

CONCLUSION

This study indicates that locating the inferior border of the external beam fields at the ischial tuberosity adequately treats at least 95.4% of all prostate patients with a margin of 1.5 centimeters or more below the prostate apex. In addition, the external beam policy of locating the inferior border at the ischial tuberosities has produced: (a) excellent 10-year clinical local control rates of 88% for Stage T1 and T2 patients and 82% for Stage T3 patients, and (b) 5-year and 10-year biochemical (normal prostate specific antigen) and clinical disease free survival rates for T1 and T2 patients which are similar to surgery.

Surgically staged patients with prostatic carcinoma treated with definitive radiotherapy: fifteen-year results

OBJECTIVE

To assess the long-term outcome of patients with lymphadenectomy-staged prostate cancer treated with external beam radiotherapy.

METHODS

A retrospective analysis was performed on all patients with prostate cancer who underwent staging pelvic lymphadenectomy before treatment with definitive radiotherapy from 1970 to February 1978. This included 71 patients who were evaluated for a minimum of fifteen years. No patients were lost to follow-up. Thirty-five patients were node negative and 36 were node positive.

RESULTS

Fifteen-year actuarial overall survival, cause-specific survival, and local control for the 20 patients with clinically organ-confined disease (T1b-T2 N0M0) was 40 percent, 75 percent, and 92 percent, respectively. The results for the 15 T3 N0M0 patients were 15 percent, 22 percent, and 60 percent. Patients with positive nodes did much worse, with rates of 5 percent, 6 percent, and 45 percent. Thirty-four patients received hormonal therapy at the time of first failure. No patient who was clinically free of disease at fifteen years had an elevated level of prostate-specific antigen (PSA).

CONCLUSIONS

Our data suggest excellent results in a cohort of patients (T1b-T2 N0M0) treated with primary radiotherapy who would be considered candidates for radical prostatectomy. Outcome is significantly worse in patients with T3 lesions and node-positive disease.

Patterns of Care and RTOG studies in prostate cancer: long-term survival, hazard rate observations, and possibilities of cure

PURPOSE

This study was undertaken to show the long-term survival and probability of cure of prostate cancer patients treated with external beam radiation in USA national surveys and in the prospective clinical trials of the RTOG.

METHODS AND MATERIALS

Two national patterns of care surveys of patients treated in 1973 and 1978 are reported along with two RTOG prospective trials (7506 and 7706). Hazard rates represent the risk of death and are compared to the rate expected for a normal population.

RESULTS

For patients with Stage A cancers, the survival is not different from the expected survival for any of the reported surveys. The hazard rate for death does not significantly exceed the expected hazard rate out to 15 years. For patients with Stage B cancer, there is a decrease in survival below expected and hazard rates show a continuing excess mortality as long as 15 years after treatment. For patients with Stage C cancers, there is a more rapid decrease in survival that then becomes parallel to the expected survival. Hazard rates indicate there has been a return to expected mortality at 15 years.

CONCLUSION

These data make a strong argument for the long-term cure of prostate cancer by external beam radiation, and support the continued use and study of radiation therapy as a curative modality in prostate cancer. No similar national data is available for any other method of management.

The effects of local and regional treatment on the metastatic outcome in prostatic carcinoma with pelvic lymph node involvement

PURPOSE

The effect of local and regional treatment on the development of distant metastases in patients with localized node negative and node positive carcinoma of the prostate is examined.

METHODS AND MATERIALS

Distant metastases-free survival was evaluated in 1078 patients with Stage B-C node negative (733 patients) or node positive (345 patients) carcinoma of the prostate, staged with pelvic lymph node dissection and treated with retropublic 125I implantation at the Memorial Sloan-Kettering Cancer Center between 1970 and 1985.

RESULTS

The 15-year actuarial distant metastases-free survival rate for the entire group of patients was 27%. Lymph node involvement was the most significant covariate affecting distant metastases-free survival, although local failure, stage, and grade were also independent variables. Distant metastases-free survival varied with the extent of lymph node involvement (N0 vs. N1, p < 0.0001; N1 vs. N2, p < 0.0001). However, the difference between N1 and N2 patients was due to a faster rate of development of distant metastases in N2 patients. The ultimate 10-year distant metastases-free survival rate was similar for the two patient groups (11% for N1 and 9% for N2). Local failure correlated with the metastatic outcome in patients with B-C/N0 disease (p < 0.00001), but not in N1 or N2 patients. Although distant metastases-free survival in locally controlled N1 patients was improved compared to N2 patients (p = 0.004), when stratified by primary tumor stage and grade, the differences were no longer significant.

CONCLUSION

Essentially all node positive patients with carcinoma of the prostate will develop distant metastatic disease if followed for sufficiently long periods of time. This is consistent with the hypothesis that in such patients distant micrometastatic dissemination already exists at the time of initial diagnosis. The data suggest that clinical trials designed to test whether improvements in local therapy impact on survival should be restricted to node negative patients. The data also raise concerns regarding the therapeutic value of elective whole pelvic irradiation.

Rate of relapse following treatment for localized prostate cancer: a critical analysis of retrospective reports

PURPOSE

Controversy exists over the optimal treatment for patients with clinically localized prostate cancer. Almost all of the treatment results are from non-randomized trials and interseries comparison is difficult since the apparent success of a treatment, as judged by the actuarial freedom from relapse and survival data, depends on patient selection criteria and post-treatment evaluation, in addition to the efficacy of the therapeutic intervention. In this report the calculation of a hazard function is used to estimate and compare the rate of relapse for the different treatments.

METHODS AND MATERIALS

Clinical reports from major surgery and radiation oncology treatment institutions were analyzed. The actuarial recurrence data were used to calculate the annual rate of recurrence within each series.

RESULTS

For all but the lowest volume tumors, patients continue to be at risk of relapse for as long as these series have been followed. Despite the heterogeneity of patient populations, the recurrence rates by stage are similar for patients treated with surgery or irradiation. This result is consistent with pathologic data from prostatectomy specimens which indicate that for lesions > 12 cm3 (approx. 3 cm in diameter) there is high likelihood of extraprostatic disease.

CONCLUSION

Treatment outcome for patients with localized prostate cancer may be more dependent on the inherent tumor biology than the particular type of treatment. Accordingly, the expectation and recommendation of a treatment must take into consideration the continued risk of relapse with either radiation therapy or surgery. There are, as yet, insufficient data regarding the impact of screening and earlier diagnosis on the curability of patients with localized prostate cancer.

Predicting the risk of lymph node involvement using the pre-treatment prostate specific antigen and Gleason score in men with clinically localized prostate cancer

PURPOSE

To evaluate the predictive value of an empirically derived equation for identifying patients with clinically localized prostate cancer at low and high risk for harboring occult lymph node metastasis.

METHODS AND MATERIALS

A simple equation for estimating the risk of positive lymph nodes was empirically derived from a nomogram published by Partin et al. demonstrating the value of combining the pre-treatment prostate specific antigen and Gleason Score in predicting the risk of lymph node metastasis for patients with clinically localized prostate cancer. The risk of positive nodes (N+) was calculated using the equation; N+ = 2/3(PSA) + (GS-6) x 10, where PSA and GS are the pre-treatment prostate specific antigen and Gleason Score respectively, and the calculated risk is constrained between 0-65% for a PSA < or = 40 ng/ml (as in the nomogram). To test the general applicability of this equation, we reviewed the pathologic features of 282 of our patients who had undergone a radical prostatectomy.

RESULTS

Based on 212 patients for whom the pre-operative prostate specific antigen's and Gleason Scores were available, we identified 145 patients with a calculated risk of positive nodes of < 15%, (low risk group) and 67 patients with a calculated risk as > or = 15% (high risk group). The observed incidence of positive nodes was 6% and 40% among the low and high risk groups respectively (p < 0.001). When used alone neither clinical stage, pre-treatment prostate specific antigen nor the pre-treatment Gleason Score was as useful in identifying the largest low and high risk groups.

CONCLUSION

Using the equation described we confirmed the general applicability of the nomogram reported by Partin et al. and identified patients at low and high risk for lymph node involvement. Based on these data we have adopted a policy of omitting whole pelvic irradiation in patients identified as low risk.

Localized carcinoma of the prostate (stages T1B, T1C, T2, and T3). Review of management with external beam radiation therapy

BACKGROUND

Optimal treatment for patients with localized carcinoma of the prostate is controversial. Radiation therapy is an established modality in the management of these patients, and several reports indicate the results are comparable to those achieved with radical prostatectomy. Recently effectiveness of therapy for carcinoma of the prostate is being evaluated in light of post-treatment prostate-specific antigen (PSA) determinations.

METHODS

A review was performed of multiple publications and data from selected institutions with large experience in the management of carcinoma of the prostate. Survival and clinical incidence of local recurrence and distant metastases were analyzed as well as preliminary data on postirradiation PSA levels. Factors that affect the outcome of therapy and relevant clinical trials are discussed.

RESULTS

Reported differences in the age of patients treated with radical prostatectomy (59-63 years), irradiation (63-69 years), or observation (69-75.5 years) were identified. The effect of surgical staging on outcome of irradiation was significant. In multiple series of patients clinically and radiographically staged, the 5-year disease-free survival (DFS) with external irradiation was 95-100% for clinical stage T1a, 80-90% for Stage T1b,c, and 50-70% for clinical Stage T3. A correlation has been identified between the initial PSA levels and the probability from freedom of chemical failure (PSA elevation) after definitive irradiation. In five series comprising 814 patients with Stage T1c and T2 tumors, the DFS (end point chemical failure) was 95%, with initial PSA of less than 4 ng/ml, 83-92% with 4.1-10 ng/ml, 35-85% with 10.1-20 ng/ml, and 10-63% with PSA higher than 20 ng/ml. In the various series, follow-up ranged from a median of 1.5 years to a minimum of 4 years. In two series of 225 and 201 patients receiving doses of 7500-8000 cGy, less morbidity has been observed with three-dimensional treatment planning conformal radiation therapy than with conventional irradiation. New directions for future clinical trials are discussed, including dose escalation studies; use of high linear energy transfer to improve locoregional tumor control; and combination of irradiation and androgen suppression to enhance local tumor control, decrease distant metastasis, and improve survival. Preliminary results of a randomized study recently reported by RTOG strongly suggest that the use of goserelin acetate and flutamide decreases the incidence of clinical local recurrence (12.4% in 225 patients) compared with a control group treated with irradiation alone (25.2% in 230 patients) and enhances disease-free survival.

CONCLUSIONS

Although modern approaches to the management of patients with localized carcinoma of the prostate with irradiation are effective, investigators must continue to critically assess policies of treatment, develop appropriately designed prospective clinical trials, and define the optimal management of patients with localized carcinoma of the prostate.

Prostate-specific antigen density: a new prognostic indicator for prostate cancer

PURPOSE

Prostate specific antigen density, previously described as a ratio of serum prostate specific antigen to the volume of the prostate, has been shown to be an important factor in the discrimination of patients with occult metastatic disease and patients with benign versus malignant prostatic disease. We undertook a retrospective study to determine if prostate specific antigen density was a predictor of outcome following definitive conformal radiation therapy.

METHODS AND MATERIALS

Between January 1989 and August 1991, 86 patients with localized prostate cancer (confined to the prostate, periprostatic tissue, or seminal vesicles) were treated in the Department of Radiation Oncology, Columbia-Presbyterian Medical Center with definitive radiation therapy using computed tomography-guided conformal technique. Thirteen patients were excluded on the basis of prior prostatectomy, hormonal therapy, or no pretreatment prostate specific antigen measurement. Seventy-three patients were evaluable: 19% (14/73) American Urologic Association Stage A (T1), 41% (30/73) B (T2), and 40% (29/73) C (T3). Prostate specific antigen density was defined as the ratio of the pretreatment serum prostate specific antigen to the prostate volume as determined from computed tomography treatment planning scans. Pretreatment prostate specific antigen density was calculated for each patient and ranged from 0.04-3.85 with a mean and median value of 0.66 and 0.33, respectively. Prostate specific antigen failure was defined as a rise above normal level or, for patients whose nadir was above 4 ng/ml, an increase of greater than 10% above nadir. Mean prostate specific antigen follow-up was 13 months (range 2.3-31 months) by which time 66% of patients had normal prostate specific antigen (< or = 4 ng/ml) levels.

RESULTS

Nine patients experienced prostate specific antigen failure. The mean prostate specific antigen density of patients with disease-free survival versus failures was 0.53 and 1.6, respectively (p < 0.05). Kaplan-Meier analysis showed that patients with a prostate specific antigen density < or = 0.3 (n = 30) had 100% actuarial disease-free survival at 30 months compared with 62% for patients with prostate specific antigen density > 0.3 (n = 43, p < 0.01). Patients with a prostate specific antigen density < or = 0.6 (n = 52) and > 0.6 (n = 21) had an 88% and 57% actuarial disease-free survival at > 24 months (p < 0.05).

CONCLUSION

Prostate specific antigen density was an excellent predictor of disease-free survival (p < 0.01) and was superior to clinical stage (p > 0.05), Gleason's score (p > 0.05), and pretreatment prostate specific antigen (p < 0.05). These results suggest that patients with low prostate specific antigen density (< or = 0.3), including those with locally advanced clinical stage, high Gleason's score, or elevated pretreatment prostate specific antigen, do well with conventional radiation therapy and should not be subjected to high risk protocols. Further follow-up will be required to determine if patients with low prostate specific antigen density will have improved overall survival.

Technical and tumor-related factors affecting outcome of definitive irradiation for localized carcinoma of the prostate

PURPOSE

The influence of some tumor-related and technical factors on therapeutic outcome is analyzed in 738 patients with histologically confirmed carcinoma of the prostate treated with definitive irradiation.

METHODS AND MATERIALS

This is a retrospective study of the records of the Radiation Oncology Center. The information was coded on computer-compatible forms and analyzed with multiple cross-reference checks to ensure data reliability. Detailed analysis of portal films and dose distribution isodose curves was carried out in 310 patients on whom this information was readily available. All patients were followed-up for a minimum of 3 years (median observation, 6.5 years).

RESULTS

Disease-free survival rates in Stages A2 (T1b) and B (T2) were 76% at 5 years and 62% at 10 years; in Stage C (T3) it was 57% at 5 years and 38% at 10 years. Overall, prostate recurrence rates were: 8% for Stage A2, 17% for Stage B, 28% for Stage C, and 46% for Stage D1 (T4). The 10-year actuarial local failure rate by stage was 20% in Stage A2 (T1b), 24% in Stage B (T2), 40% in Stage C (T3), and 70% in Stage D1 (T4) tumors. When the inferior margin of the portals was at or caudal to the ischial tuberosity, the actuarial 5-year pelvic failure rate was 0% for Stage A2 (T1b), 18% for Stage B (T2), and 20% for Stage C (T3), in contrast to 60% for Stage A2 (T1b), 27% for Stage B (T2), and 38% for Stage C (T3) when the inferior margin was cephalad to the ischial tuberosity (p = 0.05 in Stage C). Local tumor control was comparable in Stages A2 (T1b) and B (T2) when either small fields limited to the prostate and periprostatic tissues were used or, in addition, the pelvic lymph nodes were irradiated (85% and 80%, respectively). In Stage C (T3) there was significantly better pelvic tumor control (80% of 274 patients) when all of the pelvic (including common iliac) lymph nodes were treated compared with 65% in a group of 137 patients on whom the lymph nodes were irradiated with smaller fields (14 x 14 cm) (p = 0.01). In Stage C (T3), 30 patients treated with doses less than 6000 cGy had a 50% overall pelvic failure rate compared with 35% in 20 patients receiving 6500 cGy and 24% in 362 patients treated with 7000 cGy (p = 0.01). Pelvic tumor control or failure was closely associated with development of distant metastasis. In patients with pelvic tumor control, the distant metastasis rate was 18% for stages A2 (T1b) and B (T2) and 30% for stage C (T3), in contrast to 30% (p = 0.02) and 65% (p < 0.01), respectively, when prostate/pelvic failure was detected.

CONCLUSION

Volume treated and dose of irradiation are important factors influencing local/pelvic recurrence rate in carcinoma of the prostate, particularly in stage C tumors. With recent advances in three-dimensional treatment planning and conformal radiation therapy techniques, it is imperative to determine optimal volumes and doses of irradiation to be delivered to these patients while minimizing morbidity to enhance the role of irradiation in the management of localized carcinoma of the prostate.

The effect of advanced age on the efficacy of radiation therapy for early breast cancer, local prostate cancer and grade III-IV gliomas

PURPOSE

This study was undertaken to determine the effect of advanced age on radiation therapy outcomes for early breast cancer, local prostate cancer and Grade 3-4 gliomas of the brain.

METHODS AND MATERIALS

Radiation therapy outcomes for three malignancies (N = 1,401) were determined for a geriatric cancer population defined as 70 years of age or older and compared to a non-geriatric cancer population defined as less than 70 years of age. The three patient groups studied were: (a) primary breast cancer patients with clinical Stage I or II disease treated with lumpectomy and radiation therapy (N = 994), (b) local prostate cancer patients with Stage A2, B, or C disease treated with radical radiation therapy (N = 294), and (c) patients with Grade 3-4 gliomas of the brain treated with high dose radiation therapy (N = 113).

RESULTS

For Stage I and II breast cancer, there was no statistically significant difference in the overall 10-year survival rates (63% vs. 73%), 10-year cause-specific disease-free survival rates (70% vs. 63%), and 10-year local breast recurrence free survival rates (76% vs. 79%) comparing the geriatric cancer population to the non-geriatric cancer population. For local prostate cancer, there was no statistically significant difference in the 10-year survival rates (38% vs. 41%) or in the 10-year cause-specific disease-free survival rates (58% vs. 52%) in the geriatric population compared with the non-geriatric population. On the other hand, the use of high dose radiation therapy for malignant gliomas resulted in statistically significant inferior 1-year (18% vs. 38%) and 2-year (0% vs. 10%) survival rates for the geriatric population versus the non-geriatric population.

CONCLUSION

This study strongly supports the use of standard radiation therapy programs for early breast and prostate cancer patients age 70 years or more. However, our study raises questions about the efficacy of radiation therapy in patients over the age of 70 years with Grade 3-4 gliomas.

The role of the urethrogram during simulation for localized prostate cancer

Urethrograms on 89 consecutive patients with localized prostate cancer were evaluated retrospectively, and the inferior border of the treatment field based on this study was compared with the inferior border that would have been defined by using the lower border of the ischial tuberosities. An analysis of the relationship between the margin used and the dose at the inferior border of the prostate supported our policy of requiring a 2 cm margin for optimal coverage of the prostate. Inclusion of at least 1 cm of proximal penile urethra was essential to ensure this 2 cm margin. Based on this assumption, twenty-five percent of patients would have had an inadequate margin if the lower border of the ischial tuberosities had been used instead of the urethrogram to define the inferior border of the treatment field. Assuming that a margin of more than 3 cm inferiorly is excessive, 11% of patients would have had excessive urethral irradiation if the bottom of the ischial tuberosities had been used to define the inferior border. Combining these two extremes, more than one in three patients would have had an inappropriate inferior margin if the bottom of the ischial tuberosities had been used to define the inferior border of the treatment field. There was no apparent increase in morbidity as a result of the urethrograms or an increase in treatment related toxicity in association with using the treatment fields defined by urethrography. Computed tomography was complimentary in defining the apex of the prostate. These data support the routine use of the urethrograms during simulation for localized prostate cancer. The use of the lower border of the ischial tuberosities to define the inferior border of the treatment field is associated with an unacceptable risk of either underdosing the apical portion of the prostate or overdosing the urethra.

Acute toxicity during external-beam radiotherapy for localized prostate cancer: comparison of different techniques

PURPOSE

The chronic and acute toxicities associated with conventional radiotherapy of localized prostate cancer are well documented. However, the degree and incidence of toxicities with conformal techniques are not known. Studying side effects associated with modern radiotherapeutic techniques is more important now since there has been a general trend to use computerized tomography-based techniques in recent years; beam's eye view-based conformal techniques are also becoming more commonplace. It is possible that the local disease control can be improved with the delivery of higher doses than currently used. Conformation of the treatment volume to the target volume may facilitate such dose-escalation. However, prior to such dose-escalation, it is important to know the toxicities associated with such techniques with conventional doses.

METHODS AND MATERIALS

We have compared week-by-week acute toxicities associated with conventional (Group A, 16 patients), computerized tomography-based, manual (Group B, 57 patients) and beam's eye view-based (Group C, 43 patients) techniques during 7 weeks of radiotherapy. Group B and C patients were treated contemporaneously (1988-1990).

RESULTS

Acute side effects gradually increased from week 1 through weeks 4-5 and generally declined or plateaued after that. The incidence of acute toxicities was significantly less with the beam's eye view/based technique than with the other two methods. For instance, the percentages of Grade 2 acute genitourinary toxicities for Groups A, B, and C were as follows: Week 1-0, 0, 0; Week 2-6, 0, 0; Week 3-6, 9, 2; Week 4-12, 14, 9; Week 5-35, 14, 9; Week 6-31, 16, 7; Week 7-33, 8, 8, respectively. The p values associated with differences in acute genitourinary toxicities for Weeks 1-7 using chi-square test were 0.072, 0.627, 0.389, 0.538, 0.123, 0.06, and 0.012; the p values for acute gastrointestinal toxicities were 0.512, 0.09, 0.031, 0.031, 0.003, < 0.0001, and 0.004, respectively. Pairwise comparison (Wilcoxon rank-sum test) showed statistically significant lower acute toxicity in Group C than Group B (e.g., p values, Weeks 1-7 for gastrointestinal toxicity: 0.633, 0.056, 0.010, 0.014, < 0.0001, < 0.0001, and < 0.0001, respectively) in the latter part of the treatment course. No correlation was found between the extent of toxicity and the patient age or the overall treatment time. Also, no correlation was found between the degree of toxicity and the radiation dose and fraction size, within the narrow ranges used (65-70 Gy and 180-200 cGy, respectively). A trend suggesting increased severity of toxicity with increase in the volume of treatment was seen.

CONCLUSION

The findings in this retrospective study need to be confirmed by other prospective studies.

Comparison of CT-based treatment planning and retrograde urethrography in determining the prostatic apex at simulation

In 20 consecutive patients who underwent treatment planning, localization of the prostatic apex with CT-based techniques at simulation was compared to location of the apex as defined by retrograde urethrography. In addition, the location of the urethrogram-defined prostatic apex was compared with the bottom of the ischial tuberosities, which is often recommended as the inferior margin of the field. In 15% of the patients there was agreement between the CT-defined apex and the urethrogram-defined apex; in 85% there was discordance. In a majority of patients with discordance, the urethrogram apex was located caudad to the CT-defined apex (71%) with a median difference of .65 cm. In 29% of the patients the urethrogram apex was located superior to the CT-defined apex. Overall, 75% of the patients had discordance between the urethrogram apex and the CT apex of 0.5 cm or greater; 30% had an absolute difference of 1.0 cm or greater. Comparing the location of the prostatic apex with the bottom of the ischial tuberosities revealed that in 15% of the patients the apex was 1.0 cm or less from the bottom of the tuberosities and in 45% it was less than 1.5 cm. This would place the apex of the prostate in the penumbra region of the field and risk undertreatment of the prostate if the bottom of the ischial tuberosities was the inferior margin of the field. Measuring the location of the prostatic apex from the top of the symphysis pubis revealed that a distance of 4.9 cm encompassed the apex in all 20 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiation therapy in prostate cancer: whole pelvis with prostate boost or small field to prostate?

The purpose of this retrospective study is to identify prostate cancer patients who would benefit from pelvic nodes irradiation (whole pelvis) as opposed to the small-field irradiation to the prostate only. Between 1975 and 1983, 126 patients were treated by whole pelvis (4,600-5,000 cGY) with prostate boost (2,000 cGY) radiation (WP + P). Median follow-up was six years and six months. Comparison was made with historic control of 116 patients irradiated at the same institutions between 1971 and 1977 by small field to the prostate (P) to a dose of 7,000-7,500 cGY. There was a significant five-year survival improvement in the current WP + P radiation in Stage C (72% vs 40%, p = 0.0004) and Stage B (92% vs 70%, p = 0.025) but not in Stage A2 patients. However, WP + P radiation significantly improved disease-free survival (DFS) in only well and moderately but not in poorly differentiated carcinoma with a combined well and moderately differentiated five-year DFS of 63 percent compared with the 45 percent in P radiation (p = 0.0228). Local tumor control was significantly improved in WP + P radiation in only Stage C cancers with their local recurrence rate 16 percent as compared with the 34 percent in P radiation (p = 0.0172). Although acute radiation reactions were more frequent in WP + P than P radiation (61% vs 41%, p = 0.0022), chronic radiation morbidity in both series were similar. Thus, whole pelvis with prostate boost radiation should be utilized in Stage B and Stage C cancers as this has shown to increase the survival of the patient without increasing chronic radiation morbidity.

The prognostic significance of race and survival from prostate cancer based on patients irradiated on Radiation Therapy Oncology Group protocols (1976-1985)

A number of studies have identified race as a prognostic factor for survival from prostate cancer. To evaluate the prognostic significance of race in a controlled setting, we evaluated 1294 patients treated on three prospective randomized trials conducted by the Radiation Therapy Oncology Group between 1976 to 1985. One-hundred and twenty (9%) of the patients were coded as black, while 1077 (83%) of the patients were coded as white. Protocol 7506 included 607 patients with clinical Stage T3-T4Nx or T1b-T2N1-2. Protocol 7706 included 484 patients with clinical Stage T1b or T2 who were node negative. Protocol 8307 included 203 Stage T2b-T4 patients with no lymph node involvement beyond the pelvis. Univariate and multivariate analyses were used to assess the possible independent significance of race and other prognostic factors, including Gleason score, serum acid phosphatase, nodal status, and hormonal status. Protocols 7706 and 8307 revealed that race was not of prognostic significance for disease-free or overall survival by either univariate or multivariate analysis. Univariate analysis of Protocol 7506 revealed that the median survival for blacks was somewhat shorter (5.4 years vs. 7.1 years, p = 0.02). This difference persisted after a multivariate analysis. A higher percentage of blacks treated on 7506 had an abnormally elevated serum acid phosphatase compared to whites (p = 0.006), and the time to distant failure tended to be shorter (p = 0.07). These findings suggest that blacks treated on 7506 may have had more extensive disease at presentation. Based on these prospective randomized trials, it is most likely that the lower survival noted for black Americans with prostate cancer reflects the tendency for blacks to present with more advanced disease. Differences in access to care, the quality of care received, and the impact of co-morbid conditions may explain the lower survival reported for black Americans elsewhere in the literature.

Comparison of pathologic and clinical evaluation of lymph nodes in prostate cancer: implications of RTOG data for patient management and trial design and stratification

RTOG 77-06 and 75-06 were studies of nodal irradiation in prostate cancer, for which the status of nodes was determined by lymph node dissection (LND), lymphangiography (LAG), or computer assisted tomography (CT) based on investigator preference. Actuarial 5 year endpoints of survival, NED survival, local recurrence and distant metastasis have been determined by stage for 805 eligible patients with a comparison of pathologic vs clinical (imaging test) determined nodal status. Patients with pathologically negative lymph nodes show significantly improved 5 year survival (Stage T-2 (B) 84% vs 77%, Stage T-3,4 (C) 82% vs 65%) and NED survival (Stage T-2 (B) 72% vs 63%, Stage T-3,4 (C) 64% vs 44%) compared to patients clinically negative. Free of metastasis rates are increased in Stage T-3,4 (C) pathologic negative patients compared to imaging negative patients (75% vs 60%). A comparison of clinical positive versus clinical negative patients shows no difference in survival, NED survival or rate of metastasis, while a similar comparison of pathologic positive versus pathologic negative shows significant difference for all three endpoints (survival: Stage T-2 (B) 84% vs 61%, Stage T-3,4 (C) 82% vs 66%, NED survival: Stage T-2 (B) 72% vs 32%, Stage T-3,4 (C) 64% vs 32%; free of metastasis: Stage T-2 (B) 82% vs 64%, Stage T-3,4 (C) 75% vs 44%). The clinical determination of nodal status, therefore, has no prognostic value in contrast to pathologic determination and should not be used for stratifying patients in clinical trials. The CT scans often used to evaluate nodal status are more useful if delayed until they can be done as part of the treatment planning process where the CT has value. When imaging tests suggest positive lymph nodes in prostate cancer patients, the imaging finding is confirmed by biopsy.

Prognostic significance of pelvic recurrence and distant metastasis in prostate carcinoma following definitive radiotherapy

This report is a retrospective analysis of 317 patients with recurrent prostate carcinoma, following definitive radiation therapy to 738 patients with histologically confirmed, clinical Stage T1b-T4(A2-D1) adenocarcinoma of the prostate. Seventy-four patients (10%) experienced pelvic recurrence only; 100 (13%) both pelvic recurrence and distant metastasis, while 143 (20%) developed distant metastasis only. The diagnosis of prostate recurrence was histologically confirmed in 92/174 (53%), while in the others diagnosis was based on clinical and radiographic evidence. Ninety percent of all recurrences occurred within 7 years of initial treatment. The median survival from time of recurrence for all patients was 27 months, with 5-, 8-, and 10-year survival rates of 24%, 12%, and 7%, respectively. In patients who experienced pelvic recurrence only, the 5-, 8-, and 10-year survival rates were 50%, 30%, and 22%, respectively (p < 0.0001). The 5-year survival rate from time of recurrence for patients who experienced pelvic recurrence with initial Stage T1b(A2) and T2(B) disease was 71% as opposed to 39% for patients with initial Stage T3(C) disease. The time of recurrence (i.e., the disease-free interval from initial treatment) significantly affected subsequent survival: the 5-year survival rates from time of recurrence for patients with pelvic recurrence were 20%, 49%, and 94% for those who recurred within 2 years, 2 to 5 years, and more than 5 years, respectively. Two-thirds of the patients with recurrence received hormonal therapy, including bilateral orchiectomy. Salvage therapy with hormones, including bilateral orchiectomy, has a favorable impact on patient survival: The 5-year survival rate from time of pelvic recurrence salvaged with hormones was 70% compared with 21% for patients not receiving hormonal therapy. In conclusion, the prognostic factors that affect subsequent patient survival after pelvic recurrence include initial stage, disease-free interval from initial treatment, and salvage therapy with hormones. Patients with distant metastasis with or without pelvic recurrence showed statistically worse survival and were apparently not influenced by initial tumor stage, or disease-free interval from initial treatment.

Radiotherapy for prostate cancer: should the seminal vesicles be considered target?

During radiotherapy for prostate cancer, the ability to predict occult seminal vesicle invasion is important since irradiation of the entire seminal vesicles necessitates enlarging the radiation fields beyond what is usually used to irradiate the prostate gland alone. We analyzed the records of 302 patients with clinical Stage T1 or T2 adenocarcinoma of the prostate treated with radical surgery at Duke University Medical Center between 1970 and 1983. Univariate and multivariate analyses were used to examine the relationship between the risk of occult seminal vesicle involvement (defined herein as histologic involvement of the seminal vesicles not detected by physical or radiologic examination) and the following factors: histologic grade, age, clinical stage, and preoperative acid phosphatase. Among 249 patients with complete information, increasing histologic grade (p < 0.001) and clinical stage (p < 0.04) were found to be the strongest predictors of occult seminal vesicle invasion. Conversely, seminal vesicle invasion was very unusual in well-differentiated T1-T2 tumors (6%). This low risk group represented 28% (70/249) of this patient population. There appears to be a substantial subset of patients with well differentiated T1 or T2 tumors who are at very low risk for occult seminal vesicle involvement and in whom the seminal vesicles can be excluded from the target volume. The reduction in target volume may reduce normal tissue reactions, facilitate dose escalation, and possibly increase local control rates.

The effect of overall treatment time on the outcome of definitive radiotherapy for localized prostate carcinoma: the Radiation Therapy Oncology Group 75-06 and 77-06 experience

From 1976 to 1983, 1091 patients were entered into RTOG protocols 75-06 and 77-06. Of these, 780 patients complied with protocol requirements, received a minimum tumor dose of greater than or equal to 6500 cGy, and received no endocrine therapy. There were 78, 342, and 360 patients with localized prostate carcinoma, Stages T1b(A2), T2(B), and T3,4(C), respectively. The potential follow-up period ranges from 6 years 5 months to 13 years 3 months, with a median follow-up of 9 years. This study examines the influence of overall treatment time on the outcome of definitive radiotherapy for localized prostate carcinoma in this patient population. Within each stage, patients were divided into three groups according to the total number of elapsed days while on treatment: within 49 days (less than or equal to 7 weeks); 50 to 63 days (8 to 9 weeks); and greater than or equal to 64 days (greater than 9 weeks). Based on actuarial analysis, within each stage, the overall treatment time did not have any impact on the following: overall survival, NED survival, or local/regional control. When grouped under different histologic grades, that is, Gleason scores 2-5, 6-7, and 8-10, the actuarial local/regional control showed no statistical difference among the three groups. The actual local/regional failures were analyzed and stratified by stage and Gleason scores, and no statistical difference was noted among the three groups for each stratification. The range of local/regional failure rates among the three groups for T1b(A2), T2(B), and T3,4(C) disease were 0%-8%, 16%-23%, and 24%-27%, respectively. The corresponding range of local/regional failure rates for patients with Gleason scores of 2-5, 6-7, and 8-10 were 13%-14%, 18%-22%, and 22%-33%, respectively. The incidence of late complications was not related to the number of elapsed treatment days. Therefore, the overall treatment time does not have an impact on the outcome of definitive radiotherapy for localized prostate carcinoma. It is hypothesized that prostate carcinoma behaves as late-reacting tissue in which there is little, if any, accelerated repopulation of clonogenic tumor cells during the later half of a protracted course of radiotherapy. This observation is in direct contrast to that suggested for head and neck carcinoma and bears important implications in daily radiotherapeutic management of patients with prostate carcinoma.

Complications following external beam radiation therapy for prostate cancer: an analysis of patients treated with and without staging pelvic lymphadenectomy

We reviewed the treatment morbidity associated with definitive high energy external beam radiotherapy in 289 consecutive patients with clinically localized prostate cancer (stages A2 to C) treated from 1984 to 1988 inclusively. All patients were treated with 18 mv. photon beams via a 4-field box technique. Radiation doses ranged from 5,858 to 6,900 cGy., with a mean dose of 6,456 cGy. and a median dose of 6,400 cGy. A total of 65 patients underwent extraperitoneal pelvic staging lymphadenectomy before radiotherapy. Complications noted in 42 patients were mild (generally trivial) in 23 and moderate in 19 (6.6%). There were no severe complications. The actuarial incidence of moderate complications was 9% at 5 years. Only 6 patients experienced symptoms for longer than 6 months. The risk of complications was not increased in patients who had undergone prior lymph node dissection, and only 2 of 65 had mild lymphedema, which resolved in both cases. We conclude that high energy external beam radiation for prostate cancer can be delivered with a low risk of serious complications, even in patients who have undergone extraperitoneal staging pelvic lymphadenectomy, provided the patients are treated to limited fields with high energy photons and at doses limited to 6,800 cGy. or less.

Radiation therapy for the management of localized prostate carcinoma

Radiation therapy has been reported as an effective modality for the curative management of localized prostate carcinoma. In a 6 year period (1982-87), 141 patients with localized prostate carcinoma were treated at Auckland Hospital. Most patients were given radiation to the prostate alone. The overall local failure rate was 14%, with 57 patients developing distant metastases at the time of analysis. Toxicity was generally acceptable but was clearly related to the size of the treatment volume. The 5 year actuarial survival for all patients was 69.5%. Relapse-free survival rate was 39% at 5 years. Clinical stage and histological differentiation were significant factors affecting survival. Histology was a significant factor in local control. Radiation therapy for localized prostate carcinoma is effective, with a high rate of local control and low morbidity.

Outcome for lymph node dissection negative T-1b, T-2 (A-2,B) prostate cancer treated with external beam radiation therapy in RTOG 77-06

One hundred four patients with stage T-1b, T-2 N-O M-O prostate cancer were treated with external beam irradiation as part of RTOG 77-06. Lymph nodes were negative by lymph node dissection in 16 patients with T-1b and 88 patients with T-2 cancers. Survival exceeds age matched expected survival for the 10 years of observation (63% vs 59% at 10 years). Patterns of failure at 10 years show 87% of patients were free of isolated local recurrence, 79% free of metastatic failure, 67% free of any failure, and cause specific survival shows 86% free of cancer death at 10 years. The outcome of this group is equal or superior to reports of radical prostatectomy in similar stage patients.

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.

Definitive radiation therapy for localized prostatic adenocarcinoma

From 1974 to 1987, a total of 199 patients with prostatic carcinoma localized to the pelvis were treated with definitive external beam radiation therapy at the Istituto Medico e di Ricerca Scientifica. The median follow-up for all 126 surviving patients was 60 months. Actuarial 5-(and 10-) year overall survival rates for U.I.C.C. clinical Stage T1-2, T3 and T4 disease were 76.1% (58.5), 66% (42.5), and 27.6%, respectively. The corresponding 5- and 10-) year disease-specific survival rates were 81.7% (73), 72.5% (57.4), and 36.2%. The corresponding values of disease-free survival were 81.3% (76.8), 59.2% (57), and 17%, respectively. In 120 patients with more than 5 years of follow-up, local failure was seen alone in eight patients (6.6%) and associated with distant metastases in 19 patients (15.8%). In 28 patient (23.3%), distant metastases were observed alone. The median survival from the first evidence of metastases was 20 months, with no patient surviving beyond 5 years. The incidence of complications was acceptable. Serious complications, consisting of stenosis of both ureters and sigmoid colon requiring both urinary and intestinal diversion, occurred in two patients (1.3%). This study reveals that external radiotherapy is an efficacious and safe modality for locoregional control of prostate cancer.

Therapeutic options in the management of incidental carcinoma of the prostate

Incidental carcinoma of the prostate is a protean disease with a natural course which may be indolent or aggressive, with prognosis correlated with histologic grade and extent of disease. Treatment of this pathologic entity has varied over time and has been governed by institutional policy rather than randomized comparison of therapies. This report reviews the literature on incidental prostate cancer focusing on outcomes of patients as related to different therapeutic maneuvers. Observation alone with careful follow-up is appropriate therapy only for those patients with well differentiated disease of limited extent. Patients with diffuse or less differentiated disease required definitive therapy to prevent symptomatic progression. Hormonal manipulation alone has not been demonstrated to be of benefit. Radioactive implants have yielded poor disease-free survival. Radical prostatectomy by an experienced surgeon for patients with adequate health to tolerate the procedure has been associated with acceptable morbidity and excellent local control and survival. Radiation therapy has yielded similar excellent local control and survival and appears to be appropriate for a broader range of patients regardless of health or age.

Beam's eye view based prostate treatment planning: is it useful?

Prostate cancer is a common malignancy often treated with radiation therapy. Treatment optimization may improve local control while reducing acute and long-term complications. We routinely obtained CT scans on prostate cancer patients in treatment position after simulation. We analyzed the impact and implications of using our 3-D Beam's Eye View (BEV) capability on field definition and blocking for 12 consecutive patients. Conclusions include: (a) it is necessary to use multiple bony landmarks to align BEV images with simulator films; (b) it is difficult to enter volumes precisely, that is, the exact inferior extent of prostate; (c) Beam's Eye View-based plans show more individual variability in field size and position than are allowed for by recommendations in the literature; and (d) in this small series we found no significant correlation between prostate volume and clinical staging. In addition, computerized Beam's Eye View capability enables us to do normal tissue dosimetry. We have used Dose Volume Histograms (DVH) to study the impact of Beam's Eye View on optimization of dose to the bladder and rectum while adequately treating the prostate, with or without the seminal vesicles. Dose Volume Histograms using Beam's Eye View are compared with Dose Volume Histograms using target volumes from the literature. The results will be discussed, as well as the relative advantages of using Beam's Eye View for prostate cancer on a routine basis.