David Klaaßen

BACKGROUND: The combination of streptozocin and fluorouracil has become the standard therapy for advanced islet-cell carcinoma. However, doxorubicin has also been shown to be active against this type of tumor, as has chlorozotocin, a drug that is structurally similar to streptozocin but less frequently causes vomiting. METHODS: In this multicenter trial, we randomly assigned 105 patients with advanced islet-cell carcinoma to receive one of three treatment regimens: streptozocin plus fluorouracil, streptozocin plus doxorubicin, or chlorozotocin alone. The 31 patients in whom the disease did not respond to treatment were crossed over to chlorozotocin alone or to one of the combination regimens. RESULTS: Streptozocin plus doxorubicin was superior to streptozocin plus fluorouracil in terms of the rate of tumor regression, measured objectively (69 percent vs. 45 percent, P = 0.05), and the length of time to tumor progression (median, 20 vs. 6.9 months; P = 0.001). Streptozocin plus doxorubicin also had a significant advantage in terms of survival (median, 2.2 vs. 1.4 years; P = 0.004) that was accentuated when we considered long-term survival (greater than 2 years). Chlorozotocin alone produced a 30 percent regression rate, with the length of time to tumor progression and the survival time equivalent to those observed with streptozocin plus fluorouracil. Crossover therapy after the failure of either chlorozotocin alone or one of the combination regimens produced an overall response rate of only 17 percent, and the responses were transient. Toxic reactions to all regimens included vomiting, which was least severe with chlorozotocin; hematologic depression; and, with long-term therapy, renal insufficiency. CONCLUSIONS: The combination of streptozocin and doxorubicin is superior to the current standard regimen of streptozocin plus fluorouracil in the treatment of advanced islet-cell carcinoma. Chlorozotocin alone is similar in efficacy to streptozocin plus fluorouracil, but it produces fewer gastrointestinal side effects than the regimens containing streptozocin. It therefore merits study as a constituent of combination drug regimens.

One hundred ninety-one patients with pathologically confirmed, locally unresectable adenocarcinoma of the stomach (57 patients) and pancreas (91 patients), were randomly allocated to therapy with 5-fluorouracil (5-FU) alone, 600 mg/m2 intravenously (IV) once weekly, or radiation therapy, 4,000 rad, plus adjuvant 5-FU, 600 mg/m2 IV, the first three days of radiotherapy, then follow-up maintenance 5-FU, 600 mg/m2, weekly. Forty-three patients (22%) could not be analyzed because of ineligibility or cancellation, thus 148 patients were evaluable. The median survival time was similar for both treatment programs and for both types of primary carcinoma, and was as follows: gastric primary carcinoma, 5-FU, 9.3 months; 5-FU plus radiotherapy, 8.2 months; pancreatic primary carcinoma, 5-FU, 8.2 months; 5-FU plus radiotherapy, 8.3 months. Substantially more toxicity was experienced by patients treated with the combined modality arm than by those patients receiving 5-FU alone. Severe or worse toxicity experienced by patients with gastric primary carcinoma treated by 5-FU was 19%, and the combined modality arm was 31%. The toxicity experienced by patients with pancreatic primary carcinoma treated with 5-FU was 27%, and the combined modality arm was 51%. Significant prognostic variables included: weight loss in stomach-cancer patients; and performance status, degree of anaplasia, and reduced appetite in pancreas-cancer patients.

Patients with non-resectable lung cancer confined to the central area of the thorax were randomly assigned treatment with radiotherapy to the primary lesion and mediastinum (group C), and radiotherapy plus either four (group B) or eight (group A) courses of high-dose intermittent cyclophosphamide. Cyclophosphamide therapy delayed the progression of metastatic lesions outside the irradiated field (median interval to progression 192 days for groups A and B vs. 114 days for group C), and prolonged survival (median 306 days for groups A and B vs. 216 days for group C). Assuming a tumor-doubling time of 18 days, the improved survival of the cyclophosphamide-treated patients could be explained by the inhibition of 90/18 = 5 tumor doublings or a tumor cell kill of 101,5. This result indicates that cyclophosphamide is only minimally effective in the treatment of lung cancer, but it is an active drug and it should be considered for inclusion in future trials of drug combinations.

Three hundred thirty-five previously untreated patients with advanced colorectal carcinoma were randomly assigned to treatment with 5-fluorouracil (5-FU) alone, 5-FU plus N-(phosphonacetyl)-L-aspartic acid (PALA), 5-FU plus high-dose thymidine, 5-FU plus levamisole, or 5-FU plus methyl CCNU, vincristine, and streptozotocin (MOF-Strept). Dosages were designed to produce definite toxicity in the majority of patients, although the nature of dose-limiting reactions varied considerably among regimens. 5-FU alone and 5-FU plus levamisole produced mucocutaneous reactions, diarrhea, and leukopenia; 5-FU plus PALA produced primarily mucocutaneous reactions and diarrhea; 5-FU plus thymidine produced leukopenia with occasional neurotoxicity and hypotension; and MOF-Strept produced substantial nausea and vomiting with both thrombocytopenia and leukopenia. Objective response rates among patients with measurable disease varied from 12% (5-FU plus PALA) to 34% (MOF-Strept), but none of the regimens were significantly superior to 5-FU alone. Both interval to progression and survival were comparable among the five regimens with no reasonable chance that any combination regimen could produce as much as a 50% improvement when compared with 5-FU alone. Whereas we observed definite modulation of 5-FU dose--toxicity relationships, particularly with the thymidine and PALA combinations, this did not result in a detectable improvement in therapeutic effect. None of the combination regimens, administered in the dosages and schedules we used, can be recommended as standard therapy of advanced colorectal carcinoma.

A series of 1,314 cases of advanced measurable colon or rectal cancer were evaluated for objective tumor response and survival. All patients received chemotherapy according to protocols conducted by the Eastern Cooperative Oncology Group during the period between 1974 and 1977. For those patients who had not received chemotherapy prior to study entry, no therapy program under evaluations was significantly more active than the oral or intravenous 5-fluorouracil treatment programs with respect to survival or objective tumor response. The survival and response rates therapy programs under study, including methyl-CCNU, appeared to be comparable. Initial performance status (P < 0.01), weight loss in the six months prior to study entry (P < 0.001), and prior chemotherapy status were shown to be most prognostic for survival, and thus merit inclusion as stratification factors in any comparative trial involving this population. These factors were shown to have a cumulatively greater influence upon survival than the treatment program. Treatment differences were most accentuated within the favorable subgroups of the leading prognostic factors. The location of the primary tumor had a significant effect upon the eventual sites of metastatic disease involvement at the time of study entry (P < 0.001). The consequences of this analysis suggest that investigators need to address characteristics of the population under study. It is also noted that patients with chemotherapy prior to study entry are best suited for survival studies, while patients with no chemotherapy prior to study entry are well suited for both objective tumor response and survival studies.