[MOL] Found this to be interesting! [00347] Medicine On Line

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[MOL] Found this to be interesting!

Risk of Lung Cancer, COPD Elevated in Some Porphyrias

WESTPORT, Jun 03 (Reuters Health) - Patients hospitalized for certain types of porphyria are at increased risk of chronic obstructive pulmonary disease and/or lung cancer, an international research team reports. Confirming the results of previous studies, the team reports that such patients are also at increased risk of liver cancer and death from cirrhosis.

Dr. Martha S. Linet, of the National Cancer Institute in Bethesda, Maryland, and multinational colleagues used national registries in Denmark and Sweden to assess cancer incidence and mortality among 800 patients hospitalized for porphyria cutanea tarda or acute intermittent porphyria.

The standardized incidence ratio for cancer at any site was 1.7 and 1.8 among these patients, Dr. Linet's team reports in the June 1st issue of the American Journal of Epidemiology. The risk was primarily due to liver cancer, for which the standardized incidence ratio was 21.2 in patients with porphyria cutanea tarda than in the general population and 70.4 in patients with acute intermittent porphyria.

The risk of death due to cirrhosis of the liver was elevated in porphyria cutanea tarda patients, with a standardized mortality ratio of 8.4.

What was unexpected, according to the investigators, was that both groups of porphyria patients were at increased risk of lung cancer. The standardized incidence ratios were 2.9 and 2.8 in porphyria cutanea tarda and acute intermittent porphyria, respectively. In patients with porphyria cutanea tarda, the standardized mortality ratio for chronic obstructive pulmonary disease was 3.1.

"[C]igarette smoking cannot explain the threefold increase in lung cancer risk...unless virtually all of the cohort members smoked," Dr. Linet and colleagues note. "Porphyrins may enhance susceptibility to tobacco-related cancers." The authors add that if the new observations are confirmed, "...further studies will be needed to clarify the role of cigarette smoking and susceptibility mechanisms that may be involved."