The Outlook in Cancer Patients Who Previously Had Skin Cancer

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The summary below is from the full report titled "Is History of Squamous-Cell Skin Cancer a Marker of Poor Prognosis in Patients with Cancer?." It is in the 2 November 1999 issue of Annals of Internal Medicine (volume 131, pages 655-649). The authors are J. Askling, P. Sørensen, A. Ekbom, M. Frisch, M. Melbye, B. Glimelius, and H. Hjalgri.

What is the problem and what is known about it so far?

It is known that people who have previously had a common type of skin cancer (squamous-cell cancer) are at increased risk for other types of nonskin cancers. What is not known, however, is whether people who had squamous-cell skin cancer in the past do any worse when they develop other (second) cancers than people who develop these same other cancers but never had skin cancer.

Why did the researchers do this particular study?

The researchers wanted to find out whether the outlook for cancer patients who have had squamous-cell skin cancer in the past is different than that for patients with the same types of cancer who never had skin cancer.

Who was studied?

All patients 20 to 99 years of age in a cancer registry for the entire country of Sweden who had a diagnosis of cancer of the colon, breast, prostate, or lung; non-Hodgkin lymphoma; or chronic lymphocytic leukemia between 1958 and 1996.

How was the study done?

The researchers used the registry to see whether patients had a history of squamous-cell skin cancer at some point before they were diagnosed with any of the above nonskin cancers. For each type of nonskin cancer, researchers then compared the cancer death rates for patients who had also had a previous skin cancer to those who had not.

What did the researchers find?

The researchers found a total of over 400 000 patients with these various types of cancers. For patients with non-Hodgkin lymphoma; chronic lymphocytic leukemia; and cancers of the breast, colon, and prostate, those who had a history of squamous-cell skin cancer had 17% to 33% higher risks for death from the nonskin cancer than patients without a history of previous skin cancer. An association between previous skin cancer history and increased risk for death from lung cancer was present only in patients who lived for more than 1 year after their lung cancer diagnosis.

What were the limitations of the study?

These results may not apply to persons outside of Sweden or to people with types of cancers other than the ones studied. The findings also depend on the quality of the information in the cancer registry. In addition, the researchers were unable to explain why this association exists.

What are the implications of the study?

Patients with non-Hodgkin lymphoma; chronic lymphocytic leukemia; and cancer of the colon, breast, prostate, or (possibly) lung who have had squamous-cell skin cancer in the past may do worse than patients with these same cancers who have never had skin cancer. It is not known whether patients with a skin cancer history may benefit from extra powerful therapy when they develop other types of cancer.