Does the amount of muscle you have affect the course of your colorectal cancer?

This study looked at how useful the change in the amount of muscle after chemotherapy is at predicting the course of colorectal cancer.

As we age we normally lose some muscle. This limits physical activity such as exercise. In patients with cancer, lower levels of muscle can increase side effects from chemotherapy treatments. Low muscle levels have also been associated with decreased survival rates in certain types of cancer. It is not known whether muscle level affects disease progression and survival in patients with colorectal cancer. 

This study included 182 patients with colorectal cancer whose cancer could not be removed surgically. All of these patients had undergone chemotherapy. The amount of body muscle was measured both before and after chemotherapy.

Women and patients with a low body mass index (BMI, a measure of body fat based on height and weight) were significantly more likely to have a lower amount of muscle. No other factors, such as tumor location or whether the cancer had spread, were linked to the amount of muscle.

There was no association between the amount of muscle prior to chemotherapy and survival rates. Patients who lost more than 5% of their muscle following chemotherapy were twice as likely to have worse survival rates as patients who did not lose as much muscle. Progression free survival (time from treatment until the cancer progressed) was shorter in patients who lost more than 5% of muscle (9.0 months) compared to those who did not lose as much muscle (10.3 months). Overall survival was also significantly shorter in patients who lost 5% of muscle (17.2 months) compared to those who did not (28.2 months). 

The authors of the study found that loss of muscle after chemotherapy was associated with poorer outcomes for patients with colorectal cancer.

This study took place in one hospital with the authors looking back at a small number of patients' files.

Talk to your doctor about a suitable healthy exercise regime to help prevent muscle loss during treatment.