Determinants of complete remission induction and maintenance in chemotherapy with or without irradiation of small cell lung cancer.
The possible influence of pretreatment patient characteristics upon the probabilities of complete remission (CR) induction and maintenance was investigated in a series of 815 nonresected patients with small cell lung cancer. All patients underwent pretreatment staging which enabled allocation of 391 patients to trials for limited stage disease and 424 patients to trials for extensive disease. Three controlled trials for each disease stage were conducted between 1973 and 1981. All therapeutic regimens consisted of combinations of between three and six agents (lomustine, cyclophosphamide, methotrexate, vincristine, doxorubicin, etoposide) with or without irradiation. Thirty-five % of the limited stage patients and 18% of the extensive stage patients were alive and had achieved a complete remission 16 weeks after initiation of the treatment, i.e., after four cycles of chemotherapy. Relationships between pretreatment characteristics and the probability to pass this benchmark were examined by logistic regression analysis. The probability of CR was negatively related to increased serum lactate dehydrogenase and male sex in both disease stages. Pretreatment anemia (less than 12 g/liter) and poor performance status were associated with a reduced CR rate in limited and extensive stage disease, respectively. Factors related to the maintenance of complete remission were subsequently examined in the 211 complete responders by use of Cox's regression analysis. Complete responders with extensive disease prior to treatment had greater cumulative risk of relapse than those with limited disease (P less than 0.01). Hyponatremia had a significant negative influence on the remission duration in limited disease while age greater than 60 years and bone marrow metastases had significantly negative influence in extensive disease. Using the models it was possible to identify subgroups of patients with CR rates ranging from 5 to 55% and to stratify complete responders according to estimated risks of subsequent relapse.
D000328:Adult; D000368:Aged; D018288:Carcinoma, Small Cell / Q000188:drug therapy* / Q000532:radiotherapy; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy; D008297:Male; D008433:Mathematics; D008875:Middle Aged; D011379:Prognosis