Following Nutritional, Physical Activity Guidelines May Aid Colon Cancer Survival

Colon cancer survivors who adhere to healthy living guidelines may have better survival than peers who do not follow diet and physical activity recommendations

medwireNews: Stage III colon cancer survivors who follow diet and exercise guidelines may improve their long-term survival, suggest findings from the CALGB 89803/Alliance Trial.

The investigators scored 992 patients – all of whom entered the adjuvant chemotherapy study between 1999 and 2001 – according to their adherence to the American Cancer Society Nutrition and Physical Activity Guidelines for Cancer Survivors during, and in the 6 months after completing, treatment.

The advice includes maintaining a healthy body mass index, taking part in regular physical activity, and eating fruit, vegetables and whole grains, say Erin Van Blarigan, from the University of California, San Francisco, USA, and team. 
“The overall score ranged from 0 to 6, with higher scores indicating behavior more consistent with the guidelines”, the authors explain in JAMA Oncology.  

Analysis showed that patients were most likely to follow the guidelines if they were White, female and had never smoked, whereas age, use of aspirin, performance status and clinical factors did not influence score. 

Compared with patients who scored 0–1, participants with a score of 5–6 had a hazard ratio (HR) for overall survival (OS) of 0.58, after adjusting for age, sex, smoking status and clinical factors including T stage and number of positive lymph nodes.

A score of 5–6 was also associated with significantly improved disease-free survival (HR=0.69) and a trend toward better recurrence-free survival, although this did not reach significance. 

The researchers describe the relationship between adherence to advice and survival as “plausible” when considering the “extensive data” showing that the guidelines would lead to improved insulin sensitivity, reduced inflammation and improved levels of vitamin D. 

The association was stronger when patients were assigned the maximum of 2 points if they had a BMI of 23.0–29.9 kg/m2 – previously linked to improved colorectal cancer patient outcome – instead of the wider BMI range of 18.5–24.9 kg/m2, the investigators observe. 

In addition, “the results were strengthened and statistically significant for all outcomes when we included alcohol use”, they report, with HRs for OS, disease-free survival and recurrence-free survival for patients with a score of 6–8 versus 0–2 of 0.49, 0.58 and 0.64, respectively. 

At 5 years, patients with a guideline adherence score of 5–6 had a 9.0% absolute reduction in the risk of death versus those with a score of 0–4. This translates to 12 patients with stage III colon cancer adopting a guideline-consistent lifestyle for 5 years to prevent one death, the researchers calculate.

The authors of an accompanying editorial write that “[a]lthough this observational study should not be construed as an intervention causing an effect, the magnitude of the association found, a 9% absolute overall survival difference in a mature data set with median follow-up of 7 years, is certainly striking.” 

Discussing the take-home message for clinicians, Michael Fisch, from AIM Specialty Health in Chicago, Illinois, USA, and commentators say that the findings should “soften those concerns” about making nutritional and physical activity recommendations for colon cancer survivors. 

However, they acknowledge that the study included few patients who were not White or aged less than 50 years, or those with a poor performance status or a history of oxaliplatin-containing adjuvant treatment, and therefore the findings may not be generally applicable. 

Nevertheless, the editors conclude: “Behavior change is notoriously difficult at the individual and population level, but the companion study data from CALGB 89803 further strengthen the call to take aim at extending and improving lives for cancer survivors through changing behaviors related to nutrition and physical activity.”  

References

Van Blarigan EL, Fuchs CS, Niedzwiecki D, et al. Association of survival with adherence to the American Cancer Society Nutrition and Physical Activity Guidelines for cancer survivors after colon cancer diagnosis. The CALBG 898 03/Alliance Trial . JAMA Oncol; Advance online publication 12 April 2018.
DOI: 10.1001/jamaoncol.2018.0126  

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