A. G. Zaladonis1, E. O’Halloran1, M. Hill1, M. Hotz1, K. Meller1, T. Board1, M. Deng3, H. Wu2, S. Reddy1, J. M. Farma1 1Fox Chase Cancer Center,Surgical Oncology,Philadelphia, PA, USA 2Fox Chase Cancer Center,Department Of Pathology,Philadelphia, PA, USA 3Fox Chase Cancer Center,Department Of Biostatistics,Philadelphia, PA, USA
Introduction: In patients with multiple primary melanomas (MPMs), each subsequent melanoma after the first primary melanoma tends to be thinner. In patients with 3 or more primary melanomas, tumor pathology demonstrates serially increased presence of tumor infiltrating lymphocytes (TILs) and tumor regression; however, for the first 2 primary melanomas the results are variable. These phenomena of sequentially decreased tumor thickness, increased presence of TILs, and increased regression in patients with 3 or more primary melanomas may be indicative of an immunization effect. The goal of this study is to determine if this pattern is seen in patients after 2 primary melanomas and to further evaluate the possibility of an immunization effect.
Methods: Data were collected from a retrospectively maintained database at our NCI designated cancer center. Patients who had >1 primary melanoma diagnosed at least one month apart between the years of 2002 and May 2019 were reviewed. Thickness, TILs, regression, and clinical stage were compared between the first (M1) and second (M2) primary melanomas using McNemar’s Tests, and Wilcoxon Signed-Rank Tests, weight Cohen’s Kappa Tests, and exact tests of binomial proportions.
Results: A total of 65 patients, 63% (n= 41) male, who had a median age at first diagnosis of 67 (21-93) were included. Fifty-seven patients had 2 primary melanomas, 7 patients had 3 primary melanomas, and 1 patient had 6 primary melanomas. There was a median of 19 months (range 1-142) between diagnosis of M1 and M2. Clinical staging of M1 and M2 are shown in Table 1. There is no correlation between clinical stage of M1 and M2 (kappa=0.017, p=0.82). However, a greater proportion of patients had lower stage in M2 (proportion=0.71, CI: 0.54-0.84, p=0.008). Median thickness was 1.35 mm (.18-15) for M1 and 0.61 mm (0.10-25) for M2 (p=0.036), with a mean difference of 0.395 mm between them. We found no significant difference in the presence of TILs between M1 and M2 (p=0.564) or tumor regression (p=.317).
Conclusion: This study confirms the already defined trend of decreasing thickness of tumors between first and second primary melanomas. This study found no correlation between sequential primary melanomas and the presence of TILs or tumor regression. Two primary melanomas, therefore, may not be sufficient to induce an immunization effect.
