Impact of a tailored oral vitamin D supplementation regimen on serum 25-hydroxyvitamin D levels in early breast cancer patients: a randomized phase III study
Mené en France auprès de 215 patientes atteintes d'un cancer du sein de stade précoce, cet essai randomisé de phase III évalue les effets d'une supplémentation personnalisée en vitamine D à hautes doses, dispensée par voie orale, sur les niveaux sériques de vitamine D
Background : A minority of early breast cancer (EBC) patients treated with adjuvant or neoadjuvant chemotherapy have sufficient baseline vitamin D (vitD) level. This randomized phase III study assessed the safety and efficacy of a tailored, high-dose, oral vitD supplementation in restoring a normal 25-hydroxy vitD (25OHD) level in this population. Patients and Methods : Participants received a 6-month conventional (C) vitD and calcium supplementation or a 6-month high-dose oral vitD regimen tailored on the deficiency (T) and a conventional calcium supplementation. The primary endpoint was the 6-month percentage of 25OHD serum level normalization. Results : 215 patients including 197 patients with vitD deficiency were recruited, and 195 patients were randomized (T, 100; C, 95). Compliance to the daily oral supplementation was 68.4% and 67% in the C and T arms, respectively. Discontinuous high-dose vitD compliance appeared higher in the T arm (77%). At 6 months, more patients presented with a normalized vitD level in the T arm (30% vs. 12.6%; p=0.003). Supplementation was well tolerated, and no significant difference in the treatment-related toxicity between the 2 arms was reported. 52 patients without vitD normalization from the C arm switched to the T arm after 6 months. At 12 months, 44% of these patients achieved vitD normalization. Conclusion : A tailored high-dose oral vitD supplementation safely allows a higher percentage of the serum 25OHD level normalization compared with a conventional regimen in chemotherapy-treated EBC patients. As compliance to a daily oral supplementation remains poor in this setting, an adaptation of the treatment schedule is warranted.