Background: Differences in risk factors for metastases at different time intervals after treatment have been described in several malignancies; however, to the authors' knowledge, no extensive study examining this issue in melanoma has been conducted to date.
Methods: The authors performed a nested case-control study of patients with melanoma who presented with only local disease. Patients in the case group included 549 patients who developed metastases > or =6 months after surgery. Of these, 320 patients developed metastasis within 3 years after undergoing definitive surgery (early metastases [EM]), and 70 patients developed metastasis > or =8 years after undergoing definitive surgery (late metastases [LM]). For each case, a control patient was chosen who had melanoma but who did not develop metastases in the same interval. Univariate and conditional multivariate logistic regression were used in the analysis of 34 clinical and tumor characteristics.
Results: Multivariate analysis confirmed previously established risk factors for metastases, such as increasing tumor thickness. In addition, the authors discovered that a personal history of nonmelanoma skin cancer (P = .006) and a history of cancer other than skin cancer (P = .020) also were associated with metastasis. In comparing the 320 EM patients with the 70 LM patients, EM patients were more likely to have thicker lesions (P < .001), ulcerated lesions (P = .016), and a history of nonmelanoma skin cancer (P = .024).
Conclusions: In this study, 2 potentially novel risk factors for melanoma metastases were identified, and different profiles of risk factors were constructed for EM versus LM. These differences may be important in future risk identification and stratification for clinical trials and for the management and treatment of patients with melanoma.