From the Journals

RCC strongly linked to melanoma, and vice versa



A review of registry data from a major cancer center revealed a strong, bidirectional association between renal cell carcinoma (RCC) and melanoma.

A greater than twofold risk of melanoma in patients with RCC, and a nearly threefold risk of RCC in melanoma patients, were found in the review of the International Tumor Registry Database at The University of Texas MD Anderson Cancer Center.

The incidence of subsequent melanomas or RCCs in this study was in line with other recent reports from cancer registry analyses, reported Kevin B. Kim, MD, and his coinvestigators.

“Clinicians should be more watchful for these secondary cancers in patients with a history of melanoma or RCC,” they wrote. The report is in Cancer Epidemiology.

They found a total of 13,879 patients with melanoma and 7,597 patients with RCC in their review. Of those patients, 89 had both a melanoma and an RCC diagnosis. About 30% were first diagnosed with RCC, 61% were first diagnosed with melanoma, and 9% had both diagnoses around the same time.

Among the RCC-first patients, the standardized incidence ratio for developing a second primary melanoma was 2.31 (95% confidence interval, 1.52-3.37; P less than .001), while for melanoma-first patients, for developing a second primary RCC, it was 2.87 (95% CI, 2.16-3.74; P less than .001).

Those statistics were consistent with other registry reports, according to Dr. Kim and his colleagues, who wrote that the standardized incidence ratios in those studies ranged from 1.28 to 2.5.

In the MD Anderson registry study, nearly one-third of patients with secondary primary melanoma or RCC had a history of additional secondary cancers, according to the researchers. Those diagnoses included nonmelanoma skin cancers, leukemias, prostate cancer, breast cancer, and colon cancer, among others.

That suggested the presence of possible common risk factors that may have included abnormal genetics, though the database lacked the genetic sequencing and family history data to explore that hypothesis further.

“It would be highly desirable to assess germline genetic information on patients and their families, and also somatic gene aberrations in the tumor lesions, in a more systematic way in order to better elucidate the contribution of the genetics in the association between melanoma and RCC,” Dr. Kim and his colleagues said.

They reported that they had no conflicts of interest.

SOURCE: Kim KB et al. Cancer Epidemiol. 2018 Oct 19;57:80-4.

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