Risk of second primary cancer development varied by melanoma subtype, with nodular melanoma (SIR, 2.11; 95% CI, 2.03-2.18) showing the greatest risk and lentigo maligna melanoma (SIR, 1.55; 95% CI 1.50-1.61) showing the lowest risk. Nodular melanoma survivors were found to be at greatest risk for internal cancers including salivary gland cancer, sarcomas (excluding skin codes C44.0-C44.9), and thyroid cancer (p<0.05).
Clinical Pearls
In this study, Luu et al. aimed to use population data to study variation in second primary cancer development according to cutaneous melanoma subtype in cutaneous melanoma survivors.
172,637 survivors of cutaneous melanoma were studied, of which 20,696 (12%) developed second primary cancers. These results were compared to the risk of cancer in the general population.
Risk of second primary cancer development varied by melanoma subtype, with nodular melanoma (SIR, 2.11; 95% CI, 2.03-2.18) showing the greatest risk and lentigo maligna melanoma (SIR, 1.55; 95% CI 1.50-1.61) showing the lowest risk. Nodular melanoma survivors were found to be at greatest risk for internal cancers including salivary gland cancer, sarcomas (excluding skin codes C44.0-C44.9), and thyroid cancer (p<0.05).
Discussion:
Past studies have shown survivors of cutaneous melanoma are at greater risk of developing second primary cancers (SPCs) such as additional melanomas, prostate cancer, breast cancer, and non-Hodgkin lymphoma. This study by Luu et al. in the Journal of American Academy of Dermatology sought to further study this by using population data to investigate variation in second primary cancer risk by melanoma subtype.
The Surveillance, Epidemiology, and End Results (SEER) program was used to gather data from 18 separate cancer registries. Specifically, the authors used the International Classification of Diseases for Oncology, third edition histology codes to search for patients diagnosed with the major cutaneous melanoma subtypes. The authors then reported the standardized incidence ratio (SIR), the ratio of observed to the expected number of cancers, for patients who had survived a diagnosis of cutaneous melanomas compared to the general population.
The analysis included 172,637 survivors of cutaneous melanoma who then developed 20,696 (12%) second primary cancers. The risk of second primary cancer development was found to vary by cutaneous melanoma subtype, with the greatest risk in nodular melanoma (SIR, 2.11: 95% CI, 2.03-2.18) and the lowest risk in lentigo maligna melanoma (SIR, 1.55; 95% CI 1.50-1.61). Additionally, the risk for prostate cancer development was found to be elevated in only superficial spreading melanoma (SIR, 1.24; 95% CI, 1.18-1.31), nodular melanoma (SIR, 1.15; 95% CI, 1.02-1.29), and lentigo maligna melanoma (SIR, 1.21; 95% CI, 1.10-1.32).
While this study provides valuable data to help reinforce how important age-appropriate cancer screenings are for patients with and following treatment of cutaneous melanoma, the authors recognized a few weaknesses. These include low case numbers, possible misclassification of cutaneous melanoma subtype by pathologists, and limited follow up (2000-2018) which may have caused the study to be underpowered.
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