Effects of vitamin D supplementation on risks of delayed relapse or death in patients with cancer and especially in a subgroup of patients with p53-positive cancer

Interventions: Dosage, dose and duration of study supplements
Timing of start: Start blinded trial supplements from the first outpatient visit or in hospital after surgery. However, if the general condition is not good, such as strong nausea during postoperative chemotherapy, the attending physician may decide to delay the start of oral administration. However, the extension will be a maximum of 2 months from the date of surgery (the same day of the following month), and if it exceeds this, it will be excluded from the trial (= if it is excluded before the start of trial supplement [randomization], it is not a protocol violation).
Dosage and administration: Take 1 capsule once a day (at a timing that makes it easy to take in the morning or at night)
dose:
Vitamin D supplement: Vitamin D 2,000 IU / capsule
Placebo: Olive oil
Capsule material: Gelatin derived from fish, glycerin
Administration period: Administer until the end of the study, except when it becomes difficult to take the supplement. Even if it recurs, if the general condition is good, administration should be continued. When hypercalcemia or urinary stones occur and side effects of taking supplements are suspected, the oral administration can be temporarily suspended or terminated at the discretion of the attending physician.;Vitamin D;vitamin D
Primary endpoint
Events that appeared earlier due to recurrence of the cancer 365 days and more after the start of oral study supplements or death due to all causes; recurrence / death less than 365 days after the start of oral study supplements is one of the secondary endpoints.
However, subjects who reach the following conditions within 365 days * after the start of oral administration are excluded from the analysis.
a. Withdrawal of consent (refusal to take trial supplements)
b. Difficulty taking trial supplements due to complications
c. Not taking 60% and more of trial supplements; Judgment is based on the number of capsules left after having the bottle brought.
d. Transfer hospitals
On the contrary, if it is 365 days or later after the start of oral administration, the above is included in the analysis; patients who did not take the test supplement sufficiently after 1 year are also analyzed as the distribution group [intention to treat (ITT) analysis].
Cancer that newly develops in another site after the start of the supplement is not included in the recurrence and is regarded as an adverse event. If it is difficult to distinguish between recurrence and new cancer, the judgment of the research physician will be respected. This is because it is double-blind, and it is considered that the observation bias is unlikely to be mixed.
Study Design: randomized controlled trial, double blind, placebo control, parallel assignment, prevention purpose