After a cancer diagnosis, people who are single, divorced or widowed may receive less aggressive therapy, which could mean a greater risk of death, according to an article in The Washington Post.

To understand how experts might explain this phenomenon, the author of the article, cancer survivor Joan DelFattore, reviewed 59 studies from the Surveillance, Epidemiology, and End Results Program (SEER), a database run by the National Cancer Institute, showing that married adults are more likely to survive cancer than single people.

DelFattore found that study after study showed significant differences in treatment rates between married and unmarried patients. For example, single patients are far less likely to receive surgery or radiotherapy than married ones, even when it’s the treatment of choice.

One proposed explanation for these findings is that single patients, who may have less support than married ones, are more likely to refuse aggressive treatments. Other study authors wagered that unmarried patients may lack “the fighting spirit” of married patients. However, DelFattore writes: “But that explanation doesn’t stand up to scrutiny.”

In fact, researchers from Harvard, MD Anderson Cancer Center, the Mayo Clinic and others found that physician bias against single patients may have more do to with the differences in treatment and, consequently, outcomes than many providers are willing to admit. For one thing, just 0.4 percent of single patients these researchers studied in the 925,127 patient database declined surgery when their physicians recommended it. Just 0.9 percent declined radiation therapy. Absent from the studies was any mention of the role physicians might have played in treatment decisions. An alternative hypothesis for why single people receive less aggressive treatment is that they are simply not being offered it.

“The overgeneralized, unmitigatedly negative portrayal of unmarried adults is cause for concern, particularly when based on nonmedical research that is outdated or only tangentially relevant,” writes DelFattore. “It is, in effect, an invitation to associate unmarried status with a need for milder treatment, without doing enough to ascertain whether an unmarried individual could handle a more aggressive approach.”

In fact, when people are diagnosed with cancer, much support comes from family members and friends—not just spouses. But until physicians appreciate this fact, this discrepancy could be a cause for advocacy.

To learn more about this phenomenon, watch DelFattore’s recent TEDxWilmington talk, “Sick While Single? Don’t Die of Discrimination.”