MADRID - All-cause mortality is substantially lower in patients with basal cell carcinoma than in those with squamous cell carcinoma, according to a large Danish national registry study.
"In general, patients with basal cell carcinoma are in fact healthier than their counterparts with squamous cell carcinoma or age-matched controls," Dr. Gregor B. E. Jemec observed at the 13th World Congress on Cancers of the Skin, which was sponsored by the Skin Cancer Foundation.
He cited a study in which investigators at Aarhus (Denmark) University Hospital analyzed causes of death among patients with nonmelanoma skin cancer who were entered into the comprehensive Danish Cancer Registry in 1978-2001. The study population included all 82,837 Danes with basal cell carcinoma (BCC) and the 13,453 with squamous cell carcinoma (SCC) during the study years.
The all-cause mortality rate was 3% lower in the BCC cohort than the standardized rate in the general Danish population, whereas overall mortality in the SCC group was 30% greater than in the general population.
The increased all-cause mortality among patients with SCC was mainly due to excess deaths from chronic obstructive pulmonary disease, cardiovascular disease, cancer, and infectious diseases. In contrast, patients with BCC had below-average mortality from COPD, diabetes, and cardiovascular disease (Br. J. Dermatol. 2008;159:419-25).
The investigators speculated that the observed mortality benefit among patients with BCC might result in part from the salutary effects of increased serum vitamin D levels on a variety of chronic diseases.
BCC is a marker for increased sun exposure, which boosts serum vitamin D levels, which in turn has been linked in a growing number of epidemiologic studies to reduced risks of cardiovascular disease and other major causes of death.
However, the Danish registry didn't include data on vitamin D levels, so this is supposition.
Mortality from nonmelanoma skin cancer itself is quite limited. Investigators at the Danish Cancer Registry, using national data for 1984, estimated the lethality rates to be 4.3% for SCC and 0.12% for BCC (Br. J. Dermatol. 1991;125:580-2), noted Dr. Jemec, a dermatologist at the University of Copenhagen.
Nearly 74,000 deaths in the United States from 1969 to 2000 were attributed to nonmelanoma skin cancer, according to an analysis by investigators at Brown University in Providence, R.I. Almost 29,000 of these deaths were due to nonmelanoma skin cancers arising on genital skin, with a nearly 3:1 ratio of deaths attributed to vulvar and penile-scrotal cancers (J. Invest. Dermatol. 2007;127:2323-7).
Stressing avoidance of excessive sun exposure to prevent nonmelanoma skin cancer is important, but additional emphasis ought to be placed on reducing the mortality from genital nonmelanoma skin cancer, wrote Dr. Kevan G. Lewis and Dr. Martin A. Weinstock.
"The magnitude of the public health burden is great; nevertheless, efforts on the part of the dermatology community to prevent human papilloma virus infection in the United States have been slight compared to similar effort to reduce excess exposure to UV light," Dr. Lewis and Dr. Weinstock wrote.
"These data suggest that greater emphasis could be placed on the risk of mortality from genital skin cancer, both in efforts with patients and with physicians in related specialties such as family medicine and obstetrics-gynecology."
Dr. Jemec noted that the U.S. study showed sharply increasing nonmelanoma skin cancer mortality rates with each decade of age from middle age onward, and a general decline in nonmelanoma skin cancer-specific mortality during the study years.
Dr. Jemec reported having no conflicts of interest.