Improvements in cancer diagnosis and treatment have led to longer survival for most cancer patients in the United States. However, for most of the cancers studied, Whites and younger patients reaped the greatest benefits according to a recent study, conducted by Vanderbilt University researchers, and published in February’s issue of JAMA Oncology.
This study analyzed follow-up data between 1990 and 2010 obtained from nine registries of the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) program, including more than one million cancer patients diagnosed with cancer of the colon or rectum, breast, prostate, lung, liver, pancreas, or ovary.
Overall, African-Americans experienced poorer survival than Whites for all cancers, but there was variability in degree of improvement in cancer survival depending on the type of cancer. For instance, the improvement in prostate cancer survival was greater for African-American men than White men, leading to a reduced racial gap in the survival of this common cancer. But African-American women with ovarian cancer had an increased risk of death over the study period, while White women posted a slight improvement, thereby widening the racial gap for ovarian cancer survival.
The data also illustrate the dramatic improvement in outcomes in recent years for most cancer among younger patients. For example, patients aged 50 to 64 diagnosed with colon and rectum cancer between 2005 and 2009 had a 43 percent lower risk of death, compared with the same age group diagnosed with this cancer between 1990 and 1994.
For patients diagnosed with breast cancer, the reduction in risk of death was 52 percent from 1990-1994 to 2005-2009, 39 percent for liver cancer, and 68 percent for prostate cancer.
However, for older patients aged 75 to 85, the risk of death was not reduced as much, with a 12 percent lower risk for patients with breast, colon or rectum cancer, 24 percent for those with liver cancer and 35 percent for patients with prostate cancer.
“It is important to identify reasons for the slower improvement in cancer survival in elderly Americans and reduced survival rates of ovarian cancer among black Americans to inform future improvements in cancer care for all,” said Dr. Zheng, the senior author, who is director of the Vanderbilt Epidemiology Center and chief of the Division of Epidemiology.
The investigators concluded that the data suggest age- and race-related differences in survival improvements over time may be explained, at least in part, by differences in cancer care across these subpopulations.
The widening gap in cancer survival between younger and older patients may be due to differences in the use of newer treatments for elderly patients. Older patients are less likely to be enrolled in clinical trials, and thus, there is a lack of evidence regarding the efficacy of these new treatments in older patients.
The authors said their findings are a “call to action” and underscore the importance of conducting clinical trials and post-marketing studies of new therapies to identify optimal treatment regimens, necessary dose adjustments and distinct toxic effects for elderly patients. This is particularly pressing because elderly patients constitute the fastest-growing subpopulation of cancer patients in the U.S. The first author of the paper is Ms. Chenjie Zeng, a graduate student of the Vanderbilt Epidemiology Center.