More and more research studies are finding that factors like the extent of your social network or marital status versus living alone really matter when it comes to cancer.
In fact, a recent statistical study that looked at five years of U.S. data found that for five of the deadliest cancers, "the survival benefit associated with marriage was larger than the published survival benefit of chemotherapy."
In a similar vein, a study of melanoma patients in Sweden, published in May, concluded that living with someone had a larger or comparable impact on survival than the accompanying treatment for metastasized melanoma.
And a forthcoming U.S. study reports that unmarried patients are more likely to refuse surgery or radiation for their cancer, when their doctors have recommended that therapy.
The first study, by Paul Nguyen, Ayal Aizer and others, published in the Journal of Clinical Oncology in November, analyzed records from a U.S. database for 735,000 patients diagnosed from 2004 to 2008 with one of the 10 deadliest cancers.
The findings show that married patients were less likely to have a more advanced cancer when they were first diagnosed, were more likely to received the proper treatment and were less likely to die as a result of their cancer compared to unmarried patients. This is the case even after the data is adjusted for demographics, the stage of cancer and treatment.
"All things being equal, in terms of rates of treatment, stage of diagnosis, married patients are still surviving longer," Dr. Ayal Aizer, co-author of the study, told CBC News.
Aizer, a radiation oncologist at Brigham and Women's Hospital in Boston, said "the reason married patients are probably doing better after they get diagnosed with cancer than unmarried patients is because of their social support."
In other words, having a spouse served in the study as a rough proxy for a social network.
Cancer patients need both emotional and physical support to get to the doctor, to get through treatment and even for such mundane tasks as picking up their medications at the pharmacy, so social support is critical, Aizer explained.
It's not that married patients are inherently different, he said. "What we found was, it doesn't matter why patients are not married, it just matters if they are not married."
Aizer pointed to the study's finding that widows were similar in their outcomes to the never married and divorced population, rather than the married population. "So that suggests to us it really is a support-based mechanism that's driving improved outcomes in married patients versus unmarried patients."
Men living alone less likely to survive melanoma
The Sweden study looked at melanoma, which was not one of the cancers in Aizer's study.
The data covers 27,000 patients in Sweden who were diagnosed with melanoma between 1990 and 2007. Melanoma is the most serious type of skin cancer.
Researchers found that the survival odds were significantly lower for men living alone, compared to men living with a partner. This was also the case for women 70 years and older, but not for younger women. When diagnosed with melanoma, a higher proportion of these groups also had a more advanced stage of the cancer.
Dr. Hanna Eriksson, an oncologist at the Karolinska University in Stockholm and the study's lead author, told CBC News that part of the explanation is that these patients living on their own "don't perform skin examinations or have no help to do this."
Early diagnosis and treatment are crucial determinants for surviving melanoma.
"Cohabitation may provide a protective effect through early detection," Eriksson writes in the study.
In the forthcoming study, also by Aizer and his team, of why unmarried patients are more likely to refuse surgery or radiation to treat their cancer, the assumption is that "social support provided by marriage may improve adherence to recommended therapy."
That study will be published in the July 15 issue of the International Journal of Radiation Oncology.
Overall, less than one per cent of patients refuse surgery or radiation when their doctors recommend it.
Why social networks matter
So why should it be an advantage to be married or living with someone when it comes to cancer?
Aizer notes that it's men who benefit more in this regard from marriage than women, and Eriksson's data would suggest the same for living with a partner.
But as Aizer's data for breast cancer shows, women also benefit from being married when it comes to cancer. "There may be small tumours that are being picked up by the spouse that are leading patients" to get checked, he said.
But Aizer says for all 10 cancers in the study, he doesn't think it's just the stage of the cancer at diagnosis or the treatment that account for differences in survival. "There's something else, and we found that support or the presence of the spouse may be that something."
Aizer and Eriksson both say the data suggests the medical community needs to target the people who don't have that support.
Eriksson mentioned a program in Europe this year targeting older men and offering free skin examinations, as well as another one in Sweden offering skin exams to men when they come in for heart screening.
Aizer wants the medical community "to be aware that their population of unmarried patients is at risk for worse outcomes, and they should try to do things to make up for the relative lack of support, in some cases, for unmarried patients." He also encourages doctors to "get patients support who don't have it when they get diagnosed with cancer."
That may involve social workers as part of the cancer care team.
Kelly Turner, who worked as a oncological social worker, is the author of the new book, Radical Remission: Surviving Cancer Against All Odds.
She told CBC News that for the radical remission survivors that she studied, "One of the key factors for their healing was embracing their social support, receiving love from others.
"The less isolated you are, the less lonely you perceive yourself to be, consistently, study after study, you are going to live longer, and survive disease longer."
Turner often counselled single cancer patients and "often felt like I was helping them for a moment and then they were going home to this lonely abyss.
"What would be more helpful would be to really try to figure out ways to get these patients connected and involved," she added.
Will getting married help?
Which raises the question whether getting married, or starting to live with someone after a cancer diagnosis, can alter the outcome.
Turner thought that was "a fun idea" and then praised another type of matchmaking she saw in action while working at the University of California's San Francisco Medical Centre.
Cancer patients would be matched up with a survivor who had the same diagnosis. "You could call your survivor friend anytime with questions. It was a great way for survivors to give back, and it was such a wonderful service for these people who were going through it so they feel like they never had to be alone, they could always reach out and call someone."
Asked the same question, Aizer responded that it makes a good point but noted it's probably not practical. "If we can say something to patients who are not married: Draw support from people in your lives who can provide it."
Then he added, "We found that patients who rely on family, friends, community, anecdotaly, that they seem to be doing better, more happy, better able to get through things."