MONTREAL, Nov. 1 - Women with non-small-cell lung cancer (NSCLC) live longer than men, even if the disease is left untreated, researchers reported here. The average survival difference is five or six months if the disease is untreated and a year or more if the cancer is surgically removed, said Juan Wisnivesky, M.D., of the Mount Sinai School of Medicine in New York. "No matter what the treatment, women did better than men," Dr. Wisnivesky reported today at CHEST 2005, the annual meeting of the American College of Chest Physicians. The survival advantage applied to adenocarcinoma but not squamous cell carcinoma. "This suggests an intrinsic difference in the biology of the tumor," he said.
Using the Surveillance, Epidemiology and End Results (SEER) database and linking the information to Medicare records for patients older than 65, Dr. Wisnivesky and colleagues analyzed 18,967 cases of stage I and II non-small-cell lung cancer, diagnosed between 1991 and 1999.
The researchers stratified the cases by treatment -- surgery; radiation, chemotherapy or both, but not surgery; and no treatment. All told, he said, more than 12,000 patients had surgery, about 4,000 had radiation, chemotherapy, or both, and 2,200 were not treated. The investigators analyzed the survival data in three ways -- lung-cancer specific survival, all-cause mortality, and survival relative to expected survival in the general population, Dr. Wisnivesky said. All three methods showed statistically significant survival advantage for women, he said. Specifically: "No matter what treatment was used, women had better cancer-specific, overall, and relative survival than men, at the p <0.0001 confidence level for all comparisons." Lung-cancer specific five-year survival for women was 54%, compared to 40% for men and again the result was statistically significant at the p <0.0001 confidence level.
n Among untreated patients, women had approximately a 25% decreased risk of death compared to men.
Dr. Wisnivesky said the results should be used in the design and analysis of randomized controlled trials. "Maybe they should be stratified by gender," he said.
Also, he said, these epidemiological results should prompt more research on the basic biology of lung cancer.
For the clinician, he said, the findings hold out the hope of being able to being able to give more precise prognostic information, which may help informed treatment decisions. "You may decide to be more aggressive toward patients with worse prognoses," he said.
But he cautioned the finding isn't a simple yes-no decision guide that can be applied directly; more research is needed. "It's not ready right away to be incorporated by the practicing clinician," he said.
The immediate application is not clear, said Michael Alberts, M.D., chief medical officer of the F. Lee Moffitt Cancer Center in Tampa, Fla., and also president of the American College of Chest Physicians.
However, "it suggests a line of further research, looking into how hormones, for example, affect lung cancer," Dr. Alberts said.
Primary source: CHEST 2005
Source reference:
Annual meeting of American College of Chest Physicians
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