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Overall survival worse with multiple primary tumors vs. single primary tumor

Patients with multiple primary melanoma tumors demonstrated significantly worse overall survival compared with patients with one primary tumor despite a significant decrease in Breslow thickness between the first and second tumors, according to results of a retrospective study published in JAMA Dermatology.

Researchers noted that these findings suggest that patients with multiple tumors should have much stricter follow-up strategies than patients with one tumor.

“Familial atypical mole and melanoma syndrome leads to multiple primary melanomas, but primary melanoma can manifest multiple times outside the framework of familial syndromes,” Mary-Ann El Sharouni, MD, dermatologist at the University Medical Center Utrecht at Utrecht University in the Netherlands, and colleagues wrote. “Few epidemiologic data about tumor and patient characteristics of patients with multiple primary melanomas are available, necessitating better characterization of and prognostication for this group of patients.”

El Sharouni and colleagues retrospectively analyzed 56,929 patients with melanoma (mean age, 56.4 years; 56.1% women) between 2000 and 2014. Of all patients, 54,645 single primary melanoma tumors and 4,967 multiple primary tumors in 2,284 patients were included.

Data were gathered from the Dutch nationwide network and registry of histopathology and cytopathology (PALGA) and the Netherlands Cancer Registry.

Overall survival between patients with a single primary tumor compared with multiple primary tumors served as the study’s primary endpoint.

Incidence of multiple primary tumors, differences in Breslow thickness, and time between the first and second multiple primary tumors served as secondary endpoints.

Median follow-up was 75.1 months.

Results demonstrated a worse overall survival among patients with multiple primary tumors compared with patients with a single primary tumor (HR = 1.31; 95% CI, 1.2-1.42).

Median Breslow thickness decreased from 0.9 mm (interquartile range [IQR], 0.55-1.7) for the first tumor to 0.65 mm (IQR, 0.45-1.1) for the second tumor (P < .001) among patients with multiple primary tumors.

Also among these patients, 841 of 2,284 second melanomas (36.8%) were found during the first year of follow-up, and 624 of 2,284 (27.3%) were found after 5 years of follow-up.

For their second melanomas, 370 patients (16.2%) had a higher T stage, 1,112 (48.7%) had the same T stage and 802 (35.1%) had a lower T stage.

A lack of information about family history served as the study’s primary limitation. Researchers also chose not to include melanoma in situ, which could serve as a limitation.

“Because patients with multiple primary melanomas had worse survival than patients with a single primary melanoma in our multivariable analysis, we believe that a patient, once proven to have developed a second melanoma, may benefit from more thorough surveillance,” El Sharouni and colleagues wrote. “Adjuvant therapies are being developed and studied, and in the near future, their use may extend beyond patients with stage IV disease.” – by John DeRosier

Disclosures: The authors report no relevant financial disclosures.