Married people are more likely to survive cancer than those who are single, a study suggests.
Preliminary research on almost 60,000 people with a range of blood cancers found that, on average, married people were 20% more likely to survive than single people, while single men fared the worst.
Data in the study, drawn from the California Cancer Registry between 2000 and 2009, included people with leukaemia, lymphoma and multiple myeloma.
Matthew Wieduwilt, assistant clinical professor of the US blood and marrow transplantation programme and study author, said: "Single patients often present at a later stage and are sicker.
"If you are single, you don't have someone at home nagging at you to get checked out - this is particularly true with men. Women tend to have more support even if they are single.
"Married people and people with families are more likely to stick to treatment. They have a support system making them go to chemo, reminding them to take their medication. They are also more motivated to seek out healthcare. To put it bluntly, they have something to live for.
"These results show that health services need to take more care of single patients, they need to be the surrogate for a spouse."
Professor Maria Elena Martinez, of the University of California, San Diego, and co-author, said: "Being single should be a red flag for doctors. If a cancer patient comes in without a family member or spouse, it should be a warning sign.
"Medical staff need to ask the patient about the support at home. Doctors need to go that little bit extra with single patients.
"In our data, men benefit more than women from having a partner. Men tend to get more social support out of a marriage than women.
"This study reflects the wider picture. Across all cancers you are more likely to survive if you are married. It is consistent across all cancers."
Adrienne Betteley, interim head of health and social care at Macmillan Cancer Support, said: "We know that a cancer diagnosis can leave people feeling very lonely and that this can have a detrimental effect on their lives, with many forced to skip meals or attend vital appointments alone.
"At worst it can result in patients refusing treatment altogether.
"That said, it is not just those who live alone who are left feeling this way. People who have lots of social contact and that are married or have a partner can still be affected by loneliness.
"That's why it's so vital for us to reach out to people affected by cancer, even those surrounded by family and loved ones. The smallest gesture can make such a big difference."
Professor Arnie Purushotham, Cancer Research UK's senior clinical adviser, said: "While it's unclear why married people in this study seem to have better outcomes, it may be that cancer patients who have close support of partners do better and this may be due to sticking with their treatment better and a network of social support."