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Effectiveness of High Dose Vitamin D Supplementation in Stage III Colorectal Cancer

Trial Status: Closed to Accrual

This is a pilot study to test whether there is an association between baseline Vitamin D levels, Vitamin D supplementation and survival in patients with stage III colon and stage II / III rectal cancer receiving chemotherapy. 70 patients with colon stage III or rectal stage II or III cancer that require chemotherapy will be screened and 60 patients will be enrolled. Patients will be randomized to standard dose (2000 IU daily) or high-dose (50,000 IU weekly) Vitamin D supplementation for 1 year after initiation of chemotherapy. Patients' Vitamin D levels will be checked throughout supplementation then followed for 5 years with occasional Vitamin D testing and surveying in order to collect information on recurrence and survival outcomes.

Inclusion Criteria

  • Diagnosed with stage III colon or stage II/III rectal cancer that will receive neoadjuvant or adjuvant chemotherapy but have not yet started
  • Baseline serum vitamin D total 25-hydroxy level below 66 ng/ml
  • Willing to stop herbal medications as directed by physician
  • Willing to stop current supplemental vitamin D (multivitamin with vitamin D component is acceptable)
  • Willing to travel to a Legacy Health/Oregon Health & Science University (OHSU) facility if necessary
  • Agree to attend study visits outside of standard of care visits, if needed

Exclusion Criteria

  • Colon cancer stages I-II and IV or rectal cancer stage I or IV
  • Multi-focal disease (unless pre-approved by principal investigator [PI])
  • Patients who do not undergo chemotherapy
  • Patients with prior chemotherapy for this cancer
  • No other prior malignancy except for adequately treated basal cell or squamous cell skin cancer, in situ cancer, or other cancer for which the patient has been disease-free for > 3 years
  • Unwilling or unable to stop oral supplemental vitamin D
  • Patients taking high-dose vitamin D supplementation (50,000 IU weekly) prior to enrollment
  • Patients with vitamin D total 25-hydroxy level above 66 ng/ml at baseline testing
  • Patients with hypercalcemia and/or any condition resulting in malabsorption
  • Unable to comply with protocol
  • Unable to provide written informed consent
  • Investigator does not believe study participation, for any reason, is in the best interest of the patient


Legacy Good Samaritan Hospital and Medical Center
Contact: Eric C. Anderson
Phone: 503-413-8199


I. Evaluate the efficacy of D vitamin (vitamin D) supplementation in raising vitamin D levels during chemotherapy for patients with stage III colon and stage II/III rectal cancer to a standard healthy level.


I. Evaluate the efficacy of vitamin D in improving survival outcomes for patients with Stage III colon and stage II/III rectal cancer.

OUTLINE: Participants are randomized to 1 of 2 groups.

GROUP A: Beginning same day as chemotherapy treatment, participants receive standard dose of D vitamin orally (PO) daily for 1 year.

GROUP B: Beginning same day as chemotherapy treatment, participants receive high dose of D vitamin PO weekly for 1 year.

After completion of study, participants are followed up every 6 months for up to 5 years.

Trial Phase Phase II

Trial Type Treatment

Lead Organization
Legacy Good Samaritan Hospital and Medical Center

Principal Investigator
Eric C. Anderson

  • Primary ID STUDY00015051
  • Secondary IDs NCI-2018-00493
  • ID NCT02603757