That the cancer death rate for middle-aged black men has dropped by more than half in 20 years, and that thyroid cancer remains the fastest-growing cancer diagnosis in the U.S., are among the striking findings in the American Cancer Society's annual report of cancer statistics.

The cancer death rate for middle-aged black men dropped by more than half over the past two decades, and thyroid cancer remains the fastest-growing cancer diagnosis in the U.S. These are just two of the striking findings in the American Cancer Society's annual cancer statistics report, released in January.

Black men experienced the greatest drop in cancer death rates from 1991 to 2010 in every age group, with the steepest decline—at 55%—among men ages 40 to 49.

Decreases in smoking, as well as improved screening and early detection, likely contributed to the dramatic decline, says Rick Kittles, PhD, associate professor of medicine and epidemiology and biostatistics at the University of Illinois at Chicago. “There's increased literacy around cancer and health in the African-American population compared to 20 years ago,” he says.

Despite these improvements, the report notes that black men continue to have the highest cancer incidence and death rates across all races and ethnicities.

Kittles expects that the Affordable Care Act will help close that gap by increasing access to cancer screenings, timely cancer treatment, and better health care overall. “Once the Affordable Care Act really starts rolling out, the statistics for black women should change, too,” he predicts.

The new report also reveals that thyroid cancer incidence continues to rise at a faster rate than any other cancer. From 2006 to 2010, the annual incidence increased by 5.4% in men and 6.5% in women. The report estimates 62,980 Americans will be diagnosed with thyroid cancer in 2014.

About half of the increase is from small papillary thyroid tumors less than 2 cm in size, many of which are accidentally discovered on imaging done for other reasons, says James Fagin, MD, chief of the endocrinology service and member of the Human Oncology and Pathogenesis Program at Memorial Sloan-Kettering Cancer Center in New York, NY.

“Overdiagnosis of small, incidental thyroid cancers represents an important part of this increase,” Fagin says. “But it does not fully explain the increased incidence of the disease.” An increase in certain types of thyroid cancers, which are biologically different from the cancers seen 40 years ago, is also a contributing factor, he says.

“The frequency of RET rearrangements, for instance, has dramatically decreased over the past four decades, suggesting that exposure to DNA-damaging agents that can cause these chromosomal translocations has diminished,” Fagin says. “On the other hand, there's been an increase in tumors caused by point mutations of RAS.” Researchers currently do not know what causes RAS point mutations or why they are increasing in thyroid cancer, Fagin says.

What scientists do know is that small cancerous thyroid nodules are present in an estimated 6% of Americans, and many of the nodules do not need to be biopsied because most of them do not progress or increase mortality, Fagin says.

Current guidelines recommend biopsy for most thyroid nodules larger than 1 cm.