Low Glycemic Load Diet in Patients With Stage I-III Colon Cancer

A Pilot Study to Determine the Feasibility of a Low Glycemic Load Diet in Patients With Stage I-III Colon Cancer

This pilot clinical trial studies the feasibility of a low glycemic load diet in patients with stage I-III colon cancer. A low glycemic load diet includes foods that have low scores on the glycemic index. The glycemic index is a scale that measures how much a certain carbohydrate causes a person's blood sugar to rise. A low glycemic load diet may help decrease the chance of cancer coming back and improve the survival in patients with colon cancer.

PRIMARY OBJECTIVES: I. To determine the feasibility of following a low or medium glycemic load diet in patients with stage I-III (local-regional) colon cancer. SECONDARY OBJECTIVES: I. To determine patient-reported acceptability of diet. II. To determine nutritionist resources utilized. III. To evaluate the effect of lowering dietary glycemic load on body mass index (BMI), lipid metabolism and pro-oncogenic intermediaries of cellular metabolism. OUTLINE: Patients are sequentially enrolled in 1 of 4 possible cohorts as needed based on the feasibility of the prior cohort. COHORT 1: Patients follow a low glycemic load diet with standard dietary intervention (contact with nutritionist in person every 2 weeks with phone contact on the alternating weeks) for 12 weeks. COHORT 2: Patients follow a low glycemic load diet with intensified dietary intervention (contact with nutritionist in person every week) for 12 weeks. COHORT 3: Patients follow a medium glycemic load diet with standard dietary intervention for 12 weeks. COHORT 4: Patients follow a medium glycemic load diet with intensified dietary intervention for 12 weeks.

Stage I Colon Cancer, Stage II Colon Cancer, Stage III Colon Cancer, Stage I Rectal Cancer, Stage II Rectal Cancer, Stage III Rectal Cancer

Ancillary studies including three day food record, twenty-four hour dietary recall, and a food acceptability questionnaire.

Participants will be contacted by a nutritionist, in person every 2 weeks with phone contact on the alternating weeks. At the initial visit, each participant will be given verbal and written patient education materials, including low glycemic load diet recipes, meal plans, food preparation, and grocery shopping information. Individual instruction will be tailored to their baseline dietary preferences (e.g. vegan, allergies, etc).

Patients will be contacted weekly, in person, by a nutritionist . Participants will take part in a cooking demonstration at the time of their initial visit. The demonstration will be hands-on and participants will be able to sample foods and recipes. In addition to grocery shopping information, participants will be accompanied by a nutritionist to their local grocery store to practice new shopping habits for their target dietary glycemic load. Each participant will also receive weekly random phone calls to assess his or her progress.

Individual patient compliance, defined by following assigned target glycemic load index >= 75% of the time between weeks 4 and 12

This compliance rate will be determined through conducting a 24 hour telephone recall, every 2 weeks at random and calculating the glycemic load. For each dose cohort, the number and percentage of patients who are compliant will be summarized, with 90% confidence interval that accounts for the two-stage design.

Results of the acceptability survey will be tabulated and described (the questions use a 7 point likert scale), separately for each cohort.

The median number of hours will be calculated based on time spent with each patient, separately for each cohort.

Separately for each cohort, serum levels will be summarized descriptively and graphically across the follow-up period. Paired t-tests or Wilcoxon signed rank tests will be used to compare baseline vs. post-intervention levels of all biomarkers. Changes in biomarkers will be correlated with dietary glycemic index (GI) using Pearson or Spearman correlation coefficients, across the follow-up period.

Separately for each cohort, BMI levels will be summarized descriptively and graphically across the follow-up period.

Separately for each cohort, serum levels will be summarized descriptively and graphically across the follow-up period. Paired t-tests or Wilcoxon signed rank tests will be used to compare baseline vs. post-intervention levels of all biomarkers. Changes in biomarkers will be correlated with dietary GI using Pearson or Spearman correlation coefficients, across the follow-up period.

Separately for each cohort, serum levels will be summarized descriptively and graphically across the follow-up period. Paired t-tests or Wilcoxon signed rank tests will be used to compare baseline vs. post-intervention levels of all biomarkers. Changes in biomarkers will be correlated with dietary GI using Pearson or Spearman correlation coefficients, across the follow-up period.

Inclusion Criteria: Patients must have stage I-III colon or rectal cancer and have undergone definitive therapy; definitive therapy may have included surgery alone, or surgery plus neoadjuvant and/or adjuvant therapy Patients must regularly consume a diet with a glycemic load > 150 as estimated through the 3 day food recall Patients must readily be available for a 3 month period and agree to participate in regular dietary adherence assessments (surveys and phone interviews) Exclusion Criteria: Current participation in an intervention targeting diet or exercise