Body Weight and Exercise Matter

Physical activity and maintenance of a healthy body weight are known to decrease the risk of developing colorectal cancer, but until recently there was little information about whether they could influence survival after a diagnosis of colorectal cancer. To address this question, researchers in Australia conducted a study among more than 40,000 individuals.1 Information about body size and physical activity were collected at the start of the study, and study subjects were then followed over time to see who developed colorectal cancer.

During five-and-a-half years of follow-up, 526 subjects developed colorectal cancer and 208 died of the disease. After accounting for age, sex, and cancer stage, subjects who exercised had a 27% reduction in risk of death from colorectal cancer. The benefit of exercise was especially apparent for subjects with stage II or stage III cancer: In this group, subjects who exercised had a 51% reduction in risk of death from colorectal cancer.  Risk of death from colorectal cancer increased with increasing body fat and waist circumference.

The researchers conclude that a greater amount of fat in the waist and lack of regular physical activity before a colorectal cancer diagnosis result in worse colorectal cancer survival. The study unfortunately did not assess the impact of physical activity after a cancer diagnosis. Other studies, however, suggest that exercise after cancer can produce a range of benefits, including reduced fatigue, improved body image, and reduced risk of other chronic health problems such as heart disease or diabetes. Cancer survivors who are considering an exercise program may wish to talk with their doctor about a safe and effective approach.

Watching for Recurrence

A second study assessed the benefit of intensive surveillance for cancer recurrence.2 Researchers in Spain conducted a trial among 259 patients with stage II or stage III colorectal cancer. Roughly half the patients were assigned to a less-intensive surveillance strategy that involved clinical examination and blood testing. Patients at high-risk of cancer recurrence were also monitored using colonoscopy. The remaining patients were assigned to a more intensive surveillance strategy that consisted of abdominal computed tomography (CT) or ultrasound, chest X-rays, and colonoscopy, in addition to clinical examination and blood testing.

Overall, there was no significant link between type of surveillance and survival. When stage II and stage III patients were considered separately, however, a benefit was apparent for the stage II patients: In this group, patients who received more intensive surveillance survived longer than patients who received less intensive surveillance. In addition, when the researchers considered patients with colon cancer separately from patients with rectal cancer, a greater benefit was apparent for the patients with rectal cancer.

The researchers concluded that a more intensive screening strategy improved survival among patients diagnosed with stage II or rectal tumors. Because surveillance guidelines continue to evolve, colorectal cancer patients may wish to talk with their doctor about the approach that is best for them.

Many aspects of cancer survivorship are still poorly understood, but as studies such as these uncover pieces of the puzzle, survivors and their physicians will be able to make more informed decisions about how to live healthy lives after cancer.

1Haydon AMM, MacInnis RJ, English DR et al. Effect of Physical Activity and Body Size on Survival After Diagnosis With Colorectal Cancer. Gut. 2006;55:62-67.

2Rodriguez-Moranta F, Salo J, Arcusa A, et al. Postoperative Surveillance in Patients With Colorectal Cancer Who Have Undergone Curative Resection: A Prospective, Multicenter, Randomized, Controlled Trial. Journal of Clinical Oncology. 2006; 24: 386-393.