Impact of different cancer treatment modalities on dietary intake of fiber and vitamin D in colorectal cancer patients

Abstract

Abstract Importance: High intakes of fiber and vitamin D are associated with lower risk of colorectal cancer (CRC) and possibly with favorable outcomes in CRC survivors. Surgery is currently the only curative treatment for CRC. Neoadjuvant or adjuvant therapy as well as an intestinal stoma may be required. Both the disease and its treatments may result in impaired food intake. However, few studies have investigated the impact of CRC treatment on dietary intake. Objective: Investigate the impact of different treatment modalities on dietary intake of fiber and vitamin D before and after a one-year dietary intervention designed to improve the diet and lifestyle according to the recommended official dietary guidelines in Norway. Methods: A total of 250 patients with stage I-III CRC (50-80 years old) were included from the ongoing CRC-NORDIET study, where the participants were randomly assigned to either a diet intervention group or a control group. Consumption of fiber, vitamin D and different food sources contributing to intake of fiber and vitamin D were assessed at baseline and after one year of intervention by using a validated semi-quantitative food frequency questionnaire. Data on different treatment modalities were obtained from the Cancer Registry of Norway. Results: At baseline, we found that patients with a stoma had significantly lower intakes of fiber and fruits compared to those with no stoma (p=0.03 and p=0.01, respectively). Higher dietary intake of nuts was observed in patients treated with left hemicolectomy compared to those with right hemicolectomy (p=0.048) and higher in patients with laparoscopy compared to those with laparotomy (p=0.01). Left hemicolectomy patients also had a higher intake of fatty fish compared to those with right hemicolectomy or rectum resection (p=0.008). Intake of fiber, vitamin D, fruits and vegetables, fruits and fatty fish increased significantly in the intervention group compared to the control group. Patients who had underwent neoadjuvant therapy had a significantly lower increase in fruit and vegetable intake (p=0.048), and showed a reduction in fruit (p=0.04) and nut intake (p=0.005) compared to those with no neoadjuvant therapy. The left hemicolectomy patients had a significantly lower increase in fatty fish intake compared to those treated with rectum resection (p=0.04). Conclusions: The results of the present master’s thesis suggest that presence of stoma, right hemicolectomy, rectum resection and laparotomy may be related to a lower intake of certain nutrients and foods at baseline. While most of the different treatment modalities did not appear to have a major impact on changes in dietary intake after one year of dietary intervention, neoadjuvant therapy and left hemicolectomy may possibly influence the patients’ ability to change diet in accordance with the CRC-NORDIET dietary intervention.