High vs Low Dose of Vitamin D May Not Impact Treating mCRC

In patients with metastatic (spreading) colorectal cancer (mCRC), adding high-dose vitamin D3 to standard treatment did not improve progression-free survival (PFS; time a person lives without their disease getting worse) versus the standard dose of vitamin D3, except possibly in those with mCRC on the left side of their colon, an expert said.

Dr. Kimmie Ng, an associate Chief of the Division of Gastrointestinal Oncology at Dana-Farber Cancer Institute and an Associate Professor of Medicine at Harvard Medical School in Boston, spoke with CURE® on-site at the 2024 ESMO Congress, to discuss the differences in vitamin D’s dose sizes and their potential impact on clinical outcomes.

At the meeting, Ng presented findings from the phase 3 SOLARIS trial published in the Annals of Oncology, which included patients with metastatic colorectal cancer with no prior therapy. Ng and her colleagues aimed to assess the efficacy of an increased dose of vitamin D3 compared with the standard amount.

Trial results revealed no significant improvement in PFS from the addition of high-dose vitamin D3 compared with the standard dose of vitamin D3. However, there was a potential improvement seen in patients with left-sided mCRC.

The most common severe side effects including neutropenia/leukopenia (low white blood cell count), hypertension (high blood pressure), peripheral neuropathy (nerve damage in the hands and feet) and diarrhea, were not different between the standard dose and the increased dose.

Patients were treated until the disease progressed, experienced unacceptable side effects, or withdrew consent.

Transcript:

So, what we found was that, unfortunately, high doses of vitamin D added to standard treatment [for mCRC] did not seem to delay the progression of cancer any better than standard, regular doses of vitamin D, which don't tend to raise blood levels of vitamin D in the blood. And so for now, high doses of vitamin D cannot be recommended for [the] treatment of patients with metastatic colorectal cancer, although there are certainly other important benefits of vitamin D, and patients should talk to their physicians about whether they have other indications for being on vitamin D.

This transcript was edited for clarity and conciseness.

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