By Daniela Lamas, M.D.

For patients facing a cancer diagnosis, marriage means more than having a hand to hold. In fact, a husband or wife could be life-saving, suggests new, large-scale research.

A Harvard-led research team analyzed a nationwide database of nearly 750,000 patients with 10 common cancers, including breast, lung, prostate and colon cancer. They found that those who were married were more likely to get diagnosed early, before their disease had spread. They were more likely to undergo potentially curative treatment and - ultimately - 20 percent less likely to die from cancer.

Read about married cancer researchers who were both diagnosed with breast cancer.

The effect seems more powerful in men than in women. And, in patients with certain cancer diagnoses, including breast and colon, marriage seemed to improve survival even more than the quoted benefit of chemotherapy.

These are not the first findings to suggest a "survival benefit" to married cancer patients, but they're the first to confirm that this benefit exists for each of the 10 leading causes of cancer death.

But the study, published Monday in the Journal of Clinical Oncology, shouldn't be seen as a "downer" for singles, cautions Dr. Paul Nguyen, the study's senior author and an assistant professor of radiation oncology at the Dana-Farber/Brigham and Women's Cancer Center in Boston.

"This is a positive message that shows how much of a difference social support can make," says Nguyen, who notes that marriage is really a "surrogate" for a close support structure. "Something as simple as just being there for someone, going with them to their appointments, can be a powerful intervention."

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Researchers were not able to say exactly why married people with cancer seem more likely to avoid dying from it. One simple possibility, Nguyen suggests, is that patients with a spouse or partner at home are more likely to undergo recommended healthcare screening - accounting for diagnosis at an earlier stage. And if they are diagnosed with cancer, they are more likely to follow through with their treatments and appointments.

This explanation resonates with Dr. Victor Vogel, the director of breast medical oncology and research at Geisenger Health System. Vogel calls the study "very provocative," noting that in his experience, single or widowed people often have more trouble complying with tough medical regimens.

"We need to help our patients find social support throughout their illness," he says. "If there isn't a spouse to do that then we have to find other systems and networks to make that happen."

So if social support is really what matters, then how can we give cancer patients a better chance?

This is the question that occupies Dr. David Spiegel, associate chair of psychiatry and behavioral sciences at Stanford University School of Medicine. Decades ago, Spiegel showed that women with metastatic breast cancer - both married and unmarried - lived 18 months longer if they attended weekly group therapy sessions. Subsequent studies have been mixed, but researchers continue to point toward a benefit from supportive interventions, Spiegel says.

In the years since, Spiegel has turned to studying whether the effects of partnership are measurable on the biochemical level. He's found that it changes the stress hormones, markers of immune function, and even sleep quality.

"The fundamental message is that we're social creatures," Spiegel says. "We do better when we have pure and stable and supported relationships. And we do better not just psychologically and socially, but physically."

Learn the key facts and figures for breast cancer.

Doctor's Take

Just over half of American adults are married, according a recent Pew Foundation study. This study suggests that those who are not partnered and face a life-threatening illness should lean on family, friends and community. They should also not be afraid to ask doctors about support groups and tell healthcare workers if they are struggling.

Doctors and patients can work together to choose the best treatment regimen. It looks like they should also work on social support. It can be life-saving.