Coexisting Malignancies in Patients With Malignant Melanoma

Results. Forty-four (12.5%) of 352 patients with mela¬ noma had another malignancy compared with 65 (9.2%)of 704 control patients (Table). Patients with melanoma had an odds ratio of f .40 (95% confidence interval, 0.94 to 2.10) of having another malignancy compared with control patients. The increased relative risk can be ex¬ plained by a higher incidence of squamous cell carcino¬ mas in the melanoma population (27.3% vs 9.2%), and, excluding squamous cell carcinomas, no difference be¬ tween the melanoma and control population was noted. Comment. Our results confirm those of Bellet et al7 who did not find a higher frequency of noncutaneous malig¬ nancies in patients with melanoma. The higher preva¬ lence of cutaneous squamous cell carcinomas probably rep¬ resents common risk factors for both tumors, such as extensive UV exposure. Green and O'Rourke8 also found a higher incidence of other actinic tumors (actinic keratosis, basal cell carcinomas, and squamous cell carcinomas) in patients with cutaneous malignant melanomas. Other studies have found other primary malignancies in pa¬ tients with melanoma.g'n The most commonly reported as¬ sociated malignancy has been breast cancer.9,1012 Several hypothesis can explain the differences between our study and these studies. The differences could be owing to the patient population studied, inadequate control group, and researcher bias. Since we analyzed data from all patients with melanoma, we cannot exclude the possibility that a