Prostate specific antigen (PSA): impact d'un marqueur sérique sur la prise en charge diagnostique et thérapeutique des cancers de prostate

[Prostate cancer: has local radiation treatment had an impact on survival?]

Local control is an important goal in the treatment of prostate cancer. Firstly, it avoids the morbidity due to locoregional evolution (urethral obstruction, vascular compression, rectal or vesical involvement). Moreover, local control of the disease may decrease the mortality due to metastases disseminated from local relapse. Local control evaluation remains difficult: neither rectal examination nor imaging or prostate biopsies have an absolute value in diagnostic of local relapse. PSA increase does not permit to differentiate local from distant relapses. Recent developments in radiotherapy techniques allow dose escalation without major toxicity. Retrospective studies and one randomized study have shown that an increase from 70 to 80 Gy or more, improve biological relapse-free survival. In one randomized study comparing 70 to 78 Gy, the biochemical disease-free survival was improved from 69 to 79% at five years. Such an improvement can only be explained by an improvement of local control. The benefit in term of overall survival is not yet demonstrated and needs a longer follow-up and other studies. Another approach to improve local control is the association of a local radiotherapy with hormonal adjuvant therapy. Four randomized studies have been published for locally advanced prostate cancer. These studies have all demonstrated an improvement of local control, and a decrease of metastatic risk. The benefit in term of overall survival, observed in one of this trial, may be explained by the improvement of either local or distant control or both. Such therapeutic progress, associated with the development of prostate cancer screening should lead to a decrease of prostate cancer mortality for the next ten years.

[Conformal radiotherapy of prostatic cancer: a general review]

Recent progress in radiotherapeutic management of localized prostate cancer is reviewed. Clinical aspects--including dose-effect beyond 70 Gy, relative role of conformal radiation therapy techniques and of early hormonal treatment--are discussed as well as technical components--including patient immobilization, organ motion, prostate contouring, beam arrangement, 3-D treatment planning and portal imaging. The local control and biological relapse-free survival rates appear to be improved by high dose conformal radiotherapy from 20 to 30% for patients with intermediate and high risk of relapse. A benefit of overall survival is expected but not yet demonstrated. Late reactions, especially the rectal toxicity, remain moderate despite the dose escalation. However, conformal radiotherapy demands a high precision at all steps of the procedure.

[Localized prostatic adenocarcinoma: role of pelvic radiotherapy following radical prostatectomy]

Radical prostatectomy after pelvic lymphadenectomy is an effective treatment for patients with T1-2 pN0 adenocarcinoma of the prostate. However, pathologic analysis of resected tissue reveals that in 20 to 40% of clinical stage B lesions, the tumour has extended locally beyond the prostate. This infra-clinical disease may be the origin of local relapse. Radiation oncologists are often asked to deliver post-operative irradiation. There is sufficient evidence in the literature that postoperative radiation therapy can improve local control rate for patients with pT3 pN0 adenocarcinoma of the prostate; however, the effect of this radiotherapy on survival in this category of patients remains unclear. It is the reason why randomised clinical trials have been implemented for investigating the role of pelvic external irradiation with respect to the effects on local control, acute and late morbidity, overall survival and cancer-related survival, and for better defining the selective indications of radiotherapy, regarding pathological data.

[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).

[Treatment of A2-B2 prostatic cancer: results of a hormonoradiotherapy combination in the PSA era]

PURPOSE

Prospective analysis of results of combined neoadjuvant hormonetherapy and external beam radiation therapy in A2-B2 prostate adenocarcinoma.

PATIENTS AND METHODS

Between 1986 and 1994, 36 patients with clinical stage A2 (five patients), B1 (12 patients) and B2 (19 patients) N0 adenocarcinoma of the prostate declined for radical surgery, underwent a brief neoadjuvant hormonal therapy before external beam radiotherapy at our radiation therapy department. They all had a PSA determination before the combined treatment and no evidence of local extension or metastatic spread. They were followed clinically and with serial PSA levels for a median time of 58 months. Relapse was defined by a PSA level > or = 2.5 ng/mL.

RESULTS

Median pre-treatment PSA level was 16.5 ng/mL; 16 patients had less than 15 ng/mL. Combined treatment was very well tolerated. After 3 months of neoadjuvant hormonetherapy, digital rectal examination was normalized in 27 cases with a PSA value < or = 1 ng/mL in 23. Only four tumors have relapsed (one local failure, two metastases and one PSA failure). The single factor that predicted biochemical relapse was pre-treatment PSA level: the 5-year actuarial rate of PSA failure when PSA level < 15 ng/mL was 0% and 27.5% if it was > or = 15 ng/mL (p = 0.05). During follow-up, only two patients suffered grade 2 rectitis and seven complained a total impotency.

CONCLUSION

This limited study advocates hormonal neoadjuvant therapy and radiotherapy association in intracapsular prostatic carcinoma in patients declined for surgery or when pre-treatment PSA is above 15 ng/mL, with mild acute and late toxicity.

[Adjuvant radiotherapy after radical prostatectomy. Apropos of a series of 73 patients in Lyons (France)]

PURPOSE

Descriptive analysis of adjuvant radiation therapy after radical prostatectomy.

MATERIALS AND METHODS

From 1986 to 1993, 73 patients (median age, 64.5 years; Gleason score > or = 7 : 36 pts; T1:22; T2:40; T3:11) were included into the study. On the operative specimen, the cancer grades were pT2:5 (involvement of the apex), pT3:67, pT4:1, pN1-2:8. Radiation therapy was performed after a mean resting period of 112 days. The target volume was the prostatic area. The technique used was a four-field box with an 18 MV-X photon beam. The dose was 50 Gy/20 fractions/5 weeks. No hormonal treatment was administered, except for 5 patients for a short duration.

RESULTS

The median follow up was 46 months. One anastomotic local failure was salvaged by trans-urethral resection, three distant metastatic failures. Out of 72 patients with a PSA < 3 ng/mL at the end of radiotherapy, 13 showed an isolated elevation. The 5-year overall survival rate was 93%. The event-free survival was 72% after 5 years. Pathological differentiation and Gleason score were significantly correlated with the survival. There was no complication related to radiotherapy.

CONCLUSION

Elective adjuvant radiation therapy for pT3 prostate adenocarcinoma after radical prostatectomy provides a good local control with minimal morbidity.