Improvements in cancer diagnosis and treatment have led to longer survival for most cancer patients in the United States. However, the improvement in survival was substantially greater among younger patients and those who are white in most of the cancers studied, according to new research by Vanderbilt University investigators.
The study was published online recently in JAMA Oncology.
First author and graduate student Chenjie Zeng, MPH, senior author Wei Zheng, M.D., Ph.D., Anne Potter Wilson Professor of Medicine, and their collaborators examined follow-up data from 1990 to 2010 for more than 1 million cancer patients diagnosed with cancer of the colon or rectum, breast, prostate, lung, liver, pancreas or ovary.
The data was included in nine registries of the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) program.
African-Americans experienced poorer survival than whites for all cancers, but there was variability 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 there was slight survival improvement for white women with this cancer, widening the racial gap for ovarian cancer survival.
The data also illustrated the dramatic improvement in outcomes in recent years for most cancer among younger patients. For example, patients age 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 groups 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 age 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 Zheng, director of the Vanderbilt Epidemiology Center and chief of the Division of Epidemiology.
The investigators said the data suggest that 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 treatment 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.
Investigators involved with the study include Wanqing Wen, M.D., MPH, Alicia Morgans, M.D., William Pao, M.D., Ph.D., and Xiao Ou Shu, M.D., Ph.D.
The study was supported by funding from the National Institutes of Health (R37CA70867), an Ingram Professorship and the Anne Potter Wilson Chair and the Vanderbilt International Scholarship Program.
