Previous studies have shown that married patients with cancer fare better than unmarried cancer patients, surviving more often and longer. In a new study, published April 11 in the journal Cancer, researchers at University of California, San Diego School of Medicine report that the benefits of being married vary by race and ethnicity, with male non-Hispanic white bachelors experiencing the worst outcome. This group had a 24 percent higher mortality rate than their married counterparts.
Unmarried women also had higher mortality than married women, but the difference was less significant than among men. Unmarried non-Hispanic white females had a 17 percent increase in mortality compared to those who were married, while single Asian/Pacific Islander females experienced a 6 percent increase in cancer death compared to wedded counterparts.
"Oncologists should be aware that an increase in cancer mortality is a real outcome among unmarried individuals," said María Elena Martínez, PhD, UC San Diego Moores Cancer Center Sam M. Walton Endowed Chair for Cancer Research and lead author of the study. "Physicians treating unmarried patients should ask if there is someone within their social network available to help the individual physically and emotionally during treatment. More attention should be paid to this consistent and adverse health effect of being unmarried."
The number of unmarried adults in the United States is growing, from 10 percent in 1960 to 23 percent in 2012 among men and 8 to 17 percent among women. Researchers say an increase in cancer mortality is also likely to continue rising. They suggest further work to study the association between marriage and cancer mortality to help inform future decisions that may reduce cancer disparities.
In the study, comprehensive data from the California Cancer Registry were used to study 393,470 men and 389,697 women. In addition to the difference based on race and ethnicity, researchers found variation based upon place of birth. Unmarried patients born outside of the United States experienced better survivorship rates compared to those born in the U.S. There was a significant difference among women of Hispanic descent as well as males and females of Asian/Pacific Islander descent who were born in the U.S. compared to their foreign-born counterparts.
"The results suggest that the more acculturated you become to U.S. culture, the more it impacts cancer survivorship," said Martínez, co-director of the Reducing Cancer Disparities research program at Moores Cancer Center. "Our hypothesis is that non-Hispanic whites don't have the same social network as other cultures that have stronger bonds with family and friends outside of marriage. As individuals acculturate they tend to lose those bonds.
"It's also been shown that women seek out help for health concerns more frequently than men, and women tend to remind spouses to see their physicians and live a healthy lifestyle."
The data did not include information about comorbidities, changes in marital status after a cancer diagnosis or on unmarried couples living together, which may differ among different race/ethnic groups.
In a companion paper, Scarlett L. Gomez, PhD, research scientist at the Cancer Prevention Institute of California and principal investigator on the study, and other co-authors including Martinez, looked at the impact of socioeconomic status on cancer survivorship. The patterns in the Martinez-led study were minimally explained by greater economic resources among married patients, including having private health insurance and living in higher socioeconomic status neighborhoods.
Additional study co-authors include Kristin Anderson, James D. Murphy, UC San Diego; Susan Hurley, Alison J. Canchola, Cancer Prevention Institute of California; Theresa H. M. Keegan, UC Davis; Iona Cheng, Christina Clarke, Sally L. Glaser, and Scarlett L. Gomez, Cancer Prevention Institute of California and Stanford.
This research was funded, in part, by the Stanford Cancer Institute, National Cancer Institute's Surveillance, Epidemiology, and End Results (HHSN261201000140C, HHSN261201000035C, HHSN261201000034C), and Specialized Cancer Center Support Grant (CA023100-29).