PROGNOSTIC-SIGNIFICANCE OF IN-SITU CARCINOMA-ASSOCIATED WITH INVASIVEBREAST-CARCINOMA - A NATURAL EXPERIMENT IN CANCER IMMUNOLOGY

BACKGROUND. Our previous studies indicate that the in situ phase of ma mmary carcinogenesis is characteristically associated with cell-mediat ed immunity (CMI) against an immunogen shared by most breast carcinoma s. Such reactivity is inversely correlated with stage and appears to i mpede in situ-to-invasive progression and lethality from invasive brea st carcinoma. If in situ carcinomas are indeed associated with ambient , prognostically favorable immunity against such an immunogen, one wou ld expect lethality from invasive breast carcinoma to be reduced in pa tients with a diagnosis of a prior, simultaneous, or subsequent in sit u breast carcinoma. The present study provides a test of such relation ships. METHODS. Patient survival was analyzed for 129,394 female patie nts with invasive breast carcinoma diagnosed in areas covered by the S urveillance, Epidemiology, and End Results (SEER) Program based at the National Cancer Institute (NCI). Patients were classified according t o whether they had a prior, simultaneous, or subsequent in situ breast carcinoma and survival was examined for up to 15 years subsequent to diagnosis using life tables and the Cox regression model. RESULTS. The findings indicate that patients with an invasive breast carcinoma who had a prior, simultaneous, or subsequent in situ breast carcinoma did experience significantly better survival than comparison groups of pa tients who either did not have an associated cancer of any type, had a n associated invasive breast carcinoma, or had an in situ or invasive cancer of non-breast origin.CONCLUSIONS. Our prior and current observa tions warrant more direct studies of the prognostic, therapeutic, and prophylactic significance of the in situ carcinoma-associated type of specific CMI in breast cancer patients. (C) 1996 American Cancer Socie ty.