9073 Background: Melanoma incidence in the United States is expected to be 4.3% of all cancers in 2008. Cutaneous melanoma patients are at risk for second primary melanoma development. Our goal was to characterize the histopathologic features, risk factors, and patient survival for second primary melanoma. Methods: A review of the melanoma database established in 1971 at John Wayne Cancer Institute was conducted identifying patients with American Joint Committee on Cancer (AJCC) stage I and II cutaneous melanoma who later developed a second primary melanoma. Patients were grouped by Breslow thickness, Clark level, and histopathologic subtype (superficial spreading [SSM], nodular, acral lentiginous, lentigo maligna, and in situ). Multivariate analysis involving age, gender, Breslow thickness, Clark level, and ulceration status was performed to determine an effect on development of second primary. Kaplan-Meier survival curves were plotted for single primary and second primary melanoma patients. Results: Second primary melanoma was identified in 411 (3.7%) of 10,968 patients with AJCC stage I-II melanoma. The most common first primary subtype was SSM, and 93% of these patients had in situ or SSM as the second primary. Sixty-five percent of first primaries had a Breslow thickness of ≤1 mm, and 75% of second primaries had a thickness ≤1 mm. Forty-nine percent of first primaries had Clark level I or II, but 68% of second primaries had Clark level I or II. In multivariate analysis, only increasing age was significantly associated with the likelihood of second primary melanoma (p<0.0001). With increasing follow-up time the hazard ratio of second primary melanoma was 1.31 for every decade. Overall survival for second primary melanoma patients was better than for single primary patients (p<0.0001). Conclusions: Most second primary melanoma patients will have SSM or in situ, with a decreased Clark level and Breslow thickness. Contrary to expectations, patients developing second primary melanoma did not exhibit decreased overall survival. Increased follow-up time after first primary melanoma is a significant risk factor for second primary development, thus illustrating the importance of lifelong patient follow-up. No significant financial relationships to disclose.
Clark Level I