Influence of Sex on Toxicity and Treatment Outcome in Small-Cell Lung Cancer

Abstract

Female sex has been shown consistently to be a favorable prognostic factor in small-cell lung cancer (SCLC). Studies have shown that women with other tumor types experience greater treatment toxicity, but there have been few studies of sex-related toxicity in SCLC. This was a sex-based retrospective analysis of four SCLC trials conducted by the National Cancer Institute of Canada Clinical Trials Group between 1987 and 1999. The 1,006 patients (648 males and 358 females) received similar chemotherapy consisting of cyclophosphamide-doxorubicin-vincristine and etoposide-cisplatin. Toxicities examined included myelosuppression, stomatitis, vomiting, and infection. Other end points included dose reductions and omissions, response, and survival. Women experienced significantly more hematologic toxicity than men (grade 3 and 4 anemia, 16.3% v 7.6%, respectively, P < .001; grade 3 and 4 leukopenia, 80.4% v 69.2%, respectively, P = .0001). However, toxic death rates were similar for men and women (1.5% v 1.1%, respectively, P = .58). Women also had significantly more stomatitis and vomiting of all grades. Despite increased toxicity, 76% of females versus 73.4% of males received all six treatment cycles (P = .38), but 52% of females versus 43.4% of males had treatment delayed for 2 weeks or more (P = .022). Only 31.8% of females and 28.2% of males had at least one cycle of chemotherapy dose reduction (P = .23). The overall response rate was 80.3% for females and 66.9% for males (P < .0001), and the median survival time was 1.31 years for females compared with only 0.91 year for males (P < .0001). Women experience more chemotherapy-related toxicity in the treatment of SCLC, but they also have increased response rates and survival.