Cancer survivors could be putting their health at risk by being obese and failing to take enough exercise, research suggested.
A study found that breast cancer survivors were among those likely to be fat, which could make their prognosis worse.
Obesity and taking little exercise is generally linked to poor disease outcomes, the authors said.
In cancer patients, studies have have linked inactivity and being fat with recurrence of the disease, death and a reduced quality of life.
More than 114,000 people were questioned for the study, published in the journal Cancer, and asked if they had participated in any activities from a list in the past three months. The activities included walking, jogging, skiing and weight-training, and people were also asked to name activities not listed.
They were also asked how often they took part in the activity and how long each session lasted.
The authors found that fewer than 22% of survivors were physically active at the ideal level, with the lowest activity rates among female bowel cancer survivors (14%), breast cancer survivors (17%), female skin cancer survivors (19%), and male bowel cancer survivors (20%).
Just over 18% of all cancer survivors reported being obese, with little variation among the cancer survivor groups.
Obese breast cancer survivors were less likely to be active than obese women without a history of cancer.
The Canadian authors, from the University of Alberta, said the finding was consistent with a previous study "that showed that obese women reported a disproportionate decline in physical activity levels after a breast cancer diagnosis compared with non-obese women.