Association of Kaposi's sarcoma with second primary malignancies possible etiopathogenic implications

The association of Kaposi's sarcoma (KS) with second primary cancers, especially of the lymphoreticular system, has been frequently noted. To confirm these reports in a systematic way, data on a series of 92 patients with KS treated at Memorial Sloan-Kettering Cancer Center (MSKCC) 2949-1975 were subjected to extensive statistical analysis. Use was made also 4517 double primaries including all sites, diagnosed at MSKCC 1949-1974, and 1959 simultaneous double primaries from the Third National Cancer Survey. Some key results: (1) of KS patients had toher primary malignancies; (2) there was a 20-fold increase in the incidence of lymphoreticular malignancies after diagnosis of KS; (3) in the MSKCC series double primaries, lymphoreticular malignancies were involved in 8% of cases; for KS alone the corresponding figure was 58%. Our findings provide evidence in support of possible etiopathogenic mechanisms that may be involved in the natural course of KS.