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

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.

Three-dimensional conformal radiation therapy in localized carcinoma of the prostate: interim report of a phase 1 dose-escalation study

Acute morbidity, late complications and tumor response were evaluated in 324 prostate cancer patients treated with 3-dimensional conformal radiation therapy in a phase I dose-escalation study. This radiotherapy technique targeted the prostate and seminal vesicles but effectively excluded the surrounding normal tissues. The minimum tumor dose was 64.8 to 66.6 Gy. in 87 patients, 70.2 Gy. in 138, 75.6 Gy. in 69 and 81.0 Gy. in 30. The treatment was well tolerated with minimal acute morbidity, observed in 15% of the patients who required medication for relief of rectal symptoms and in 34% for urinary symptoms. Two patients (0.6%) to date have had grades 3 and 4 late complications (Radiation Therapy Oncology Group morbidity grading system). The 3-year actuarial probability of survival with a normal serum prostate specific antigen level was 97% for patients with stages T1c and T2a, 86% with stage T2b, 60% with stage T2c and 43% with stage T3 disease. A multivariate analysis demonstrated that initial prostate specific antigen (20 ng./ml. or less versus more than 20 ng./ml.), stage (T2c or less versus T3) and Gleason score (6 or less versus 7 or more) were each significant independent variables that affected subsequent chemical relapse. The acute and long-term toxicities have been less compared with traditional treatment techniques. After the maximal tolerable dose with 3-dimensional conformal radiotherapy is established, future studies will test whether high dose conformal therapy has the potential to improve local tumor control and survival of patients with localized prostatic carcinoma.

Three-dimensional conformal radiation therapy in locally advanced carcinoma of the prostate: preliminary results of a phase I dose-escalation study

PURPOSE

The acute morbidity of doses of 64.8-75.6 Gy and preliminary observations of late complications and tumor response using 3-dimensional conformal radiation therapy in carcinoma of the prostate are assessed.

METHODS AND MATERIALS

123 patients (Stage A2-12, B1-17, B2-43, C-51) were irradiated to the prostate and seminal vesicles using a 3-dimensional conformal radiation therapy technique. The median follow-up time was 15.2 months. The minimum tumor dose was 64.8-66.6 Gy in 49 patients, 70.2 Gy in 46, and 75.6 Gy in 28. Toxicity was scored according to the Radiation Therapy Oncology Group morbidity grading system.

RESULTS

This technique of 3-dimensional conformal radiation therapy was well-tolerated with minimal acute morbidity. Only 32% of patients had grade 2 or 3 acute morbidity requiring short-term medication for relief of urinary symptoms or diarrhea. Only one patient (0.8%) has so far developed a severe (grade 4) late complication. Serum prostate specific antigen concentrations normalized in 67% of patients (64/96) within 1-14 months (median 4.5 months) after treatment and were progressively decreasing at last measurement in an additional 22% (21/96). Abnormal rising prostate specific antigen levels were observed in 15 patients, 11 of whom have already developed other evidence of relapsing disease.

CONCLUSION

Acute toxicity for the doses tested with this 3-dimensional conformal radiation therapy technique is reduced compared to traditional treatment techniques, and the initial tumor response as assessed by prostate specific antigen measurement is highly encouraging with prostate specific antigen levels returning to normal in the majority of patients. Based on these results, a further increase of the dose to 81 Gy has been implemented in accordance with the schema of an ongoing Phase I dose-escalation study.