Treatment of stage D prostatic carcinoma with megestrol acetate

Megestrol acetate in the treatment of hormone refractory prostate cancer

This retrospective study evaluates the efficacy of megestrol acetate in patients with hormone refractory metastatic adenocarcinoma of the prostate. Data are presented from 14 patients with advanced prostatic adenocarcinoma who were treated with 160-320 mg of megestrol acetate daily. Each patient was either asymptomatic or had minimal cancer-related symptoms. Disease response was monitored by prostate-specific antigen levels. The response rate was 14%, with two patients having a partial response. No complete responses were observed. The median time to disease progression was 2 months. Our findings when considered together with results from previously published data demonstrate little activity of megestrol acetate in patients with hormone refractory prostate cancer. Therefore, we cannot recommend megestrol acetate as an effective second-line therapy.

Phase II trial of hormonal cytoreduction with megestrol and diethylstilbestrol in conjunction with radiotherapy for carcinoma of the prostate: outcome results of RTOG 83-07

PURPOSE

RTOG 83-07 is a Phase II randomized protocol designed to compare the efficacy and toxicity of Megestrol vs. Diethylstilbestrol (DES) used as cytoreductive agents prior to and during radiotherapy. The end points of this study include tumor clearance rate, effect on serum testosterone, loco-regional control, disease-free interval, and survival.

METHODS AND MATERIALS

Eligible patients were those with histologically confirmed locally advanced adenocarcinoma, clinical Stage B2 (T2B) and C (T3) without regional lymph node involvement, or with lymph node involvement limited to the pelvis. Patients were stratified by clinical stage, histological grade, and nodal status, and were randomized to receive either Megestrol 40 mg three times per day by mouth, or Diethylstilbestrol 1 mg three times per day by mouth. The drugs were started 2 months prior to initiation of radiotherapy and were continued throughout the radiotherapy course. Radiotherapy consisted of 44-46 Gy, 1.8-2 Gy per day to the regional lymphatics, followed by a boost to the prostate consisting of 20-25 Gy, 1.8-2 Gy per day, to a total of 65-70 Gy. Serum testosterone levels were recorded throughout the treatment course. Tumor response was assessed clinically and radiographically (CT scan). From March 1983 through June 1986 a total of 203 patients were accessioned to the study; 198 were analyzable.

RESULTS

Correlation of the incidence of drug-related toxicity and treatment arm assignment revealed a significantly higher incidence of complications in the Diethylstilbestrol (DES) arm. The most prominent were the differences in the incidence of gynecomastia (55% vs. 7%) and fluid retention (21% vs. 6%). The incidence of thromboembolic phenomena was comparable (8% vs. 5% in the Megestrol arm). Patients on the DES arm demonstrated a significantly greater median decrease in testosterone level. Correlation of the treatment arm assignment and the rate of tumor regression and the incidence of complete response revealed no significant difference between the arms. At 7 years, 16% of patients on the Megace arm and 21% of patients on the DES arm manifested evidence of local failure.

CONCLUSIONS

The results of the study indicate comparable efficacy (using tumor clearance as an end point) of DES and Megestrol. Although DES appears more effective in suppressing testosterone, it is also associated with a higher incidence of drug-related toxicity.

Hormonal cytoreduction in locally advanced carcinoma of the prostate treated with definitive radiotherapy: preliminary results of RTOG 83-07

RTOG 83-07 is a Phase II randomized protocol designed to compare the efficacy and toxicity of Megestrol vs Diethylstilbestrol (DES) used as cytoreductive agents prior to and during radiotherapy. The end-points of this study include tumor clearance rate, effect on serum testosterone, local-regional control, disease-free interval, and survival. Eligible patients were those with histologically confirmed locally advanced adenocarcinoma, clinical Stage B2 and C without regional lymph node involvement, or with lymph node involvement limited to the pelvis. Patients with medical conditions potentially predisposing to cardiovascular (thromboembolic) sequelae of endocrine therapy were not eligible. Patients were stratified by clinical stage, histological grade, and nodal status and were randomized to receive either Megestrol 40 mg PO tid or Diethylstilbestrol 1 mg PO tid. The drugs were started 2 months prior to initiation of radiotherapy and were continued throughout the radiotherapy course. Radiotherapy consisted of 44 to 46 Gy, 1.8 to 2 Gy per day to the regional lymphatics followed by a boost to the prostate consisting of 20 to 25 Gy, 1.8 to 2 Gy per day to a total of 65 to 70 Gy. Serum testosterone levels were recorded throughout the treatment course. Tumor response was assessed clinically and radiographically (CT scan). From March 1983 through June 1986 a total of 203 patients were accessioned to the study; 197 were analyzable. Correlation of the incidence of drug related toxicity and treatment arm assignment revealed a significantly higher incidence of complications in the Diethylstilbestrol (DES) arm. The most prominent were the differences in the incidence of gynecomastia (55% vs 7%) and fluid retention (21% vs 6%). The incidence of thromboembolic phenomena was comparable (8% vs 5% in the Megestrol arm). Although patients on the DES arm demonstrated a significantly greater median decrease in testosterone level, correlation of the treatment assigned to the rate of tumor regression and the incidence of complete response revealed no significant difference between the arms. At 3 years only 6.5% of the evaluable patients manifested evidence of local failure. The results of the study indicate comparable efficacy (using tumor clearance as an end-point) of DES and Megestrol. While DES appears more effective in suppressing testosterone it is also associated with a higher incidence of toxicity. The cytoreduction (using either DES, Megestrol, or an alternative regimen) concept remains to be tested in a Phase III study comparing it to radiotherapy alone.

Systemic treatment for prostate cancer

Prostate cancer is a leading cause of cancer mortality in adult men. The majority of patients have subclinical systemic disease at diagnosis and will eventually require systemic therapy for palliation of symptoms. Recent development of new hormonal treatment options (e.g., gonadotropin-releasing hormone analogues and estramustine) has yet to demonstrate potential for improving the therapeutic index or for lengthening survival over results achieved with traditional modalities (i.e., supplemental estrogens or castration). Chemotherapeutic agents have demonstrated palliative efficacy and are being tested in multidrug regimens and in combination with hormones. At the present time, the optimal use of cytotoxic drugs remains undefined, since recently published studies have shown neither that combination chemotherapy is superior to single agents nor that chemo-hormonal therapy produces more favorable results than hormonal treatment alone.

Phase II study of megestrol acetate for metastatic carcinoma of the prostate

Forty-three males with recurrent and metastatic cancer of the prostate were treated with megestrol acetate (160 mg/day orally) after having failed first-line hormonal treatment (orchiectomy or diethylstilboestrol). Thirty-seven patients were evaluated objectively for response, 28 of whom received the drug for more than 6 weeks. One patient had a partial response (National Prostatic Cancer Project criteria) and seven had stable disease. Toxicity was usually mild, although five patients developed a transient rise in liver enzymes and one patient had a grand mal fit. Three patients showed evidence of tumour "flare". Megestrol acetate has only limited efficacy in patients previously treated for prostatic cancer by hormonal manipulation.

Phase II trial with D-Trp-6-LH-RH in prostatic carcinoma: comparison with other hormonal agents

Various approaches to hormonal treatment of prostate carcinoma are discussed. Eighty-one patients with prostatic carcinoma, eight with stage B, nine with stage C, and 64 with stage D disease, were treated subcutaneously daily for 3 months with the LH-RH agonist D-Trp-6-LH-RH (Decapeptyl) in order to evaluate the incidence of remissions according to WHO recommendations for oncologic trials. The findings were compared to those obtained with other hormonal therapies of prostatic carcinoma according to the statistical method of "expected response rate" as adapted by Lee and Wesley for phase II trials. Treatment with D-Trp-6-LH-RH greatly reduced serum LH and testosterone levels without raising serum prolactin. After 1-2 weeks of therapy, there was relief of subjective symptoms and a reversal of the signs of prostatism as well as a marked decrease in bone pain. At 90 days 52 patients had complete relief of prostatism and 21 had only mild signs and symptoms. Seventy patients were experiencing no bone pain and an additional six had only mild pain. Prostatic size, evaluated by rectal examination and transabdominal ultrasonography, reverted to normal in 26.4% of patients (complete remission) and was reduced by more than 50% in an additional 17.6% (partial remission), the overall rate of complete plus partial regression of prostatic enlargement being 44%. Scans showed a major improvement of bone lesions in 14.8% of cases. This response increased to 37% after more than 6 months of follow-up. Prostatic acid phosphatase levels were decreased by more than 50% in 61% of the patients, but this test appears to be a less valid marker than the lipid-associated sialic acid (LASA). The increase in LASA before treatment and a reduction after treatment can frequently be correlated with the objective volume of the neoplasms. No flare-up of the disease was encountered, and there were no side effects except for impotence. Statistical analyses of results by the method of Lee and Wesley indicated that the incidence of complete and partial regression (CR and PR) observed with D-Trp-6-LH-RH was not significantly different from that recorded in previous studies for another LH-RH analog, Buserelin. However, CR and PR obtained with D-Trp-6-LH-RH (44%) were significantly higher than with subcapsular orchiectomy (22%). Hormonal effects and some other actions of D-Trp-6-LH-RH were compared and contrasted with those produced by castration, estrogens, antiandrogens, and progestogens.(ABSTRACT TRUNCATED AT 400 WORDS)