Primary malignant neoplasms associated with chronic lymphocytic leukemia.

Over the past 2 decades there has been an almost exponential increase in the frequency with which cases of leukemia associated with another primary malignant lesion have been reported. In this study we reported the occurrence of a second primary neoplasm to 82 consecutive cases of chronic lymphocytic leukemia (CLL) admitted to the Istituto Nazionale Tumori of Milan from September 1962 to December 1978. In 16 of these (19.5%), an assoicated neoplasm was diagnosed subsequently (8 cases) or concurrently (8 cases) to CLL. Head and neck carcinomas and breast cancer had the highest incidence (5 and 3 cases, respectively). The results of this study further support the hypothesis that patients with CLL are prone to develop subsequent cancer. The defective cellular and humoral immunity in CLL may have an etiological role in the development of an additional primary malignancy. Although alkylating agents are known carcinogens in experimental animals and man, our results support the lack of a correlation between treatment with alkylating agents and incidence of second primary neoplasms, as demonstrated by Greene et al. (10).