Cutaneous melanoma is often diagnosed in young and middleaged individuals. After a melanoma diagnosis, patients are understandably concerned about their risk of a second melanoma and about cancers of all types. After treatment of a primary cancer, the focus for many people moves to detection and prevention of further malignancies. Conversely, patients diagnosed with other cancers may be concerned about their risk of melanoma. Recently, several population-based studies have confirmed associations between melanoma and particular types of other cancer. Genetic links are being identified between melanoma and other cancers.

For many young patients, a skin cancer diagnosis is their first personal cancer diagnosis. This news can strike people in different ways, and fortunately many become motivated to focus on early skin cancer detection and prevention of further skin cancers. As with any diagnosis of “cancer,” questions are often raised about the risks of other types of cancer for an individual or their family members.

For patients with other primary cancers, the risk of developing melanoma is increased relative to the general population. As the incidence of melanoma increases and survival rates increase for patients with melanoma, more and more people are living longer after a melanoma diagnosis. Knowing the relative risks of different cancers for an individual with a history of melanoma can help allay fears and promote age-appropriate cancer screening.

Previous studies have found a link between an initial cutaneous malignant melanoma diagnosis and later diagnosis of lymphoma,^1,2 breast cancer,^3–5 thyroid cancer,⁶ pancreatic cancer,^7–9 bladder cancer,¹⁰ and nervous system cancer,¹¹ as well as second primary melanoma^12,13 and non-melanoma skin cancers.^14,15

Fortunately, researchers in the United States (U.S.) and beyond are utilizing large and now-long-term databases to assess relative risks of different cancers. In the United States, the National Cancer Institute's SEER (Surveillance, Epidemiology, and End Results) database tracks de-identified data for all cancer diagnoses in 17 geographical areas from 1973 to the present. The malignancies are reported to the SEER database by diagnosing pathologists, and the SEER organization collects clinical information and de-identifies patient information into a database. This database is updated and a new set is released annually. Researchers can query this database to look at cancer incidence, outcomes, and reports of issues such as second primary malignancies. Patients are followed annually with the SEER database until their death or are lost to follow up for other reasons such as a move out of the geographic area.

Geographical regions represented by the SEER database include Atlanta, GA; Detroit, MI; the San Francisco Bay Area; Los Angeles, CA; the State of Hawaii; the State of Iowa; the State of Kentucky; the State of Louisiana; the State of New Jersey; the State of New Mexico; the Seattle-Puget Sound region; and the State of Utah.

In addition to geographical regions, different databases track cancers in Native American populations. Separate registries track cancers among the Alaska native population, Arizona Indian population, and the Cherokee Nation.

On an international level, the International Agency for Research on Cancer (IARC) aggregates data from 13 non-U.S. cancer registries that have been in operation for at least 25 years. The registries include New South Wales in Australia, British Columbia, Manitoba and Saskatchewan in Canada, Denmark, Finland, Iceland, Norway, Scotland, Singapore, Slovenia, Sweden and Zaragoza in Spain. These registries follow cancer data covering different time periods beginning in 1943.

The largest database query to date of SEER regarding melanoma was recently published. Spanogle et al. at Stanford University¹⁶ analyzed 151,996 individuals with a diagnosis of cutaneous malignant melanoma in the SEER database between 1973 and 2003. This population was larger than previously per-