Coexistence of renal cell carcinoma and malignant lymphoma. A causal relationship or coincidental occurrence?

Secondary malignant neoplasms are increasingly being observed in cancer populations and a considerable amount of data have accumulated in the literature. Among the secondary malignant neoplasms that occur with a higher incidence in cancer patients are lymphomas and renal cell carcinoma (RCC), as well as melanoma, lung/bronchus carcinoma.

The authors analyzed the patient population at the Memorial Sloan-Kettering Cancer Center in New York City between 1985 and 1995 for coexisting carcinomas, and identified 15 patients who had both RCC and malignant lymphoma among a total of 1262 patients with RCC and 1660 patients with malignant lymphoma. The occurrence and time of diagnosis of both malignant neoplasms and their clinical features, types, and stages, as well as short term follow-up, results, are presented.

The data show a greater than coincidental coexistence of RCC and malignant lymphoma (P < 0.01). In addition, there was a significant increase in the number of patients with both melanoma and RCC (P < 0.01), as well as melanoma and malignant lymphoma (P < 0.01). No significant increase was found in cases of coexisting RCC or malignant lymphoma with either lung/bronchus carcinoma or colorectal carcinoma (P > 0.05).

Causes of this increased coexistence may include a genetic predisposition to cancer, similar immune mechanisms associated with these neoplasms, closer scrutiny of this group of patients, or a combination of these factors. Studies are underway to elucidate a common genetic component in these patients.