Unmarried men were 27 percent more likely to die of their tumors, and single women were 19 percent more likely, the study found.
Married people generally had better health insurance and lived in better neighborhoods, but single patients still fared worse even after accounting for these financial reasons for the marriage advantage.
“It seems that the major contributing factor is greater social support, and less social isolation, among married patients,” said study leader Scarlett Lin Gomez of the University of California, San Diego.
“Having a strong support system can have meaningful impacts on the odds of survival after a cancer diagnosis,” Lin added by email.
The research team studied nearly 783,000 patients diagnosed with cancer in California from 2000 through 2009, including about 387,000 who had died by 2012.
They focused on patients with invasive malignancies and their 10 most common causes of cancer deaths.
Once researchers adjusted for insurance status and neighborhood socioeconomic status, unmarried men were 22 percent more likely to die than their peers who had tied the knot, and single women were 15 percent more likely to die.
At the start of the study, 70 percent of the men and 51 percent of the women were married, and nearly all patients had some type of health insurance.
Unmarried patients were more likely to be black, live in low-income neighborhoods, be uninsured or have government insurance, be diagnosed at a later stage of disease, and not receive any surgery or radiation.
Uninsured men and women had about 25 percent higher odds of death than people with private health insurance.
The findings don’t prove single life causes death from cancer, however. It’s also possible that certain characteristics that lead people to marry, such as being physically or emotionally healthier than people who don’t find mates, might influence patients’ survival odds, the authors note in the journal Cancer.
The results also don’t make cancer death a foregone conclusion for single people, study coauthor Maria Elena Martinez of the University of California, San Diego added by email.
“Single patients should take advantage of their support networks, even if they do not necessarily have spouses or children to turn to during a cancer diagnosis,” Martinez said. “This is particularly important for male patients.”
That’s because research suggests that men benefit more socially from marriage, said Catherine Powers-James, a psychology researcher at the University of Texas MD Anderson Cancer Center.
“Although both men and women may think they are being a burden on others when they ask for help, women are more inclined to reach out to others for emotional support and for assistance,” Powers-James, who wasn’t involved in the study, said by email.
Single patients who don’t have close friends might consider seeking professional help from a therapist, Powers-James added.
Not all marriages are the same, or equally strong in times of crisis. But the findings suggest it’s worth investigating what aspects of these long-term relationships may be most responsible for better survival odds, since money clearly isn’t the only thing in play.
“To the extent that the U.S. will be seeing a greater number of cancer patients and survivors due to the aging of our population, coupled with a rising proportion of unmarried individuals, we can look further into the possible ways that being married translates into improved cancer survival so that we can use the information to help all patients,” Martinez said.