Men who are diagnosed with cancer are more likely to die from the disease than women, due to a higher initial risk and later detection, U.S. government research showed.
The National Cancer Institute study looked at a database of 36 different types of cancer from 1977 to 2006.
It found the highest male-to-female mortality rate ratios for cancers like lip, where 5.5 men died for each woman patient, and esophageal, where 4 men died for each woman patient.
For lung cancer, which is the leading cause of cancer deaths for both men and women, the research found 2.3 male deaths for each female death.
The main reason for the difference is that men are more at risk of developing cancer to begin with, according to Michael Cook, an investigator in the division of cancer epidemiology and genetics at the NCI and the study's lead investigator.
The average lifetime chance that a man will develop lung cancer is about 1 in 13, compared to 1 in 16 for a woman, according to the American Cancer Society.
American men are more likely than women to have advanced disease by the time their cancer is diagnosed, Cook said.
He said gender differences in exposure to carcinogens — including tobacco smoke and viral infections — play a role in the rate disparity. The study also cited "universal" mechanisms, such as sex chromosomes and hormones, that may contribute to observed sex differences in cancer incidence.
The NCI researchers said there was no single root cause for the rate disparity, but influences include differences in behavior of the tumor, cancer screening for people without symptoms, presence of other illnesses and whether patients sought healthcare services.
A recent survey conducted by Abbott Laboratories found that 28 percent of men do not visit the doctor regularly.