The cancer death rate in the United States has dropped by 25 percent since its 1991 peak, resulting in 2 million fewer cancer deaths than if the rate had stayed the same, the American Cancer Society said Thursday in a new report.

The group attributed the decrease largely to reductions in smoking and improvements in the early detection and treatment of cancer. But there remains a significant gender gap: The cancer death rate is 40 percent higher for men than women, and the incidence of cancer is 20 percent higher in men.

Almut Horch works with a microscope system behind a monitor where cancer cells are visualized in Jena, Germany. Associated Press/Jens Meyer

That gender disparity reflects differences in the kind of cancers that men and women develop. For example, liver cancer, which is often lethal, is three times more common in men, largely because of higher rates of hepatitis C infection, smoking and excess alcohol consumption among men. The largest sex disparities are for cancers of the esophagus, larynx and bladder; incidence and death rates are four times higher in men, the report said.

For 2017, the report estimated, there will be nearly 1.7 million new cancer diagnoses and more than 600,000 deaths. The most common causes are lung, colorectal and prostate malignancies in men, and lung, breast and colorectal cancers in women. These account for almost half of all cancer deaths.

The report found that racial disparities in cancer death rates continue to decrease, although the cancer death rate remains 15 percent higher in blacks than in whites.

“The continuing drops in the cancer death rate are a powerful sign of the potential we have to reduce cancer’s deadly toll,” said Otis Brawley, the cancer society’s chief medical officer. “Continuing that success will require more clinical and basic research to improve early detection and treatment, as well as creative new strategies to increase healthy behaviors nationwide.”