Non‐Hodgkin's lymphoma and skin malignancies‐shared etiology?

Abstract

The Stockholm‐Gotland Cancer Register was used to evaluate the clinical observation that patients with non‐Hodgkin's lymphoma (NHL) had an increased risk of malignant melanoma or squamous‐cell carcinoma of the skin (SCCS) and vice verso. During 1958–1992, NHL was diagnosed in a total of 6,176 patients. Of these patients, 504 developed a second primary cancer of any type except NHL, compared to 301.9 expected, giving a standardized incidence ratio (SIR) of 1.7 [95% confidence interval (Cl) 1.5–1.8]. The risk of SCCS and malignant melanoma in patients with NHL was 4.8 (95% Cl 3.6–6.2; n = 54) and 1.7 (95% Cl 0.8–3.1; n = 10), respectively. The hazard risk for a second malignancy was relatively constant over time, whereas the skin malignancies revealed the highest risks 3–10 years after initial diagnosis. Similarly, the risk of a secondary NHL was studied in patients with malignant melanoma and SCCS during the same period and found to be 1.3 (95% Cl 0.8‐2.1; n = 17) and 1.8 (95% Cl 1.2–2.5; n = 34), respectively. The highest risk for NHL following malignant melanoma was seen 3–10 years after first diagnosis, while the highest risk following SCCS was observed 0‐2 years after initial diagnosis. One of several possible explanations for the development of NHL and a skin malignancy in the same patient is an immunological defect caused by sun exposure.