Intrapleural adaptive immunotherapy for breast cancer patients with cytologically-confirmed malignant pleural effusions: an analysis of 67 patients in Kyoto and Shiga Prefecture, Japan.

Sixty-seven breast cancer patients with cytologically-confirmed malignant pleural effusion, who required intrapleural treatment, were analyzed retrospectively. The patients received their first thoracentesis between 1980 and 1990. Among them, 29 patients received intrapleural administration of OK-432, a streptococcal preparation, followed by the transfer of autologous pleural effusion lymphocytes cultured with interleukin-2. Other intrapleural treatments consisted of OK-432 alone (12 patients), chemotherapeutic agents alone (n = 9), a combination of OK-432 and chemotherapy (n = 16), or others (n = 1). Twenty-six of the 29 patients given OK-432 plus cultured effusion lymphocytes responded, while only 15 of the 38 patients who received other treatments did (p < 0.01). Median survival time and 5-year survival rate of patients who received OK-432 and cultured lymphocytes was 12 months and 36%, while those of the patients who received other treatments was 3 months and 0%, a significant (p < 0.001) difference in survival. Multivariate analysis using Cox's proportional hazard model revealed that the treatment (adoptive immunotherapy) was the most significant (p < 0.005) factor to prolong the survival of the patients among several prognostic factors. Thus, OK-432 and adoptive immunotherapy is a promising therapy that should be further evaluated in a prospective study.