S0-called alternative medicine (SCAM) is often promoted for improving the quality of life (QoL) of cancer patients. Women with early-stage breast cancer often opt for trying SCAM. One such option is vitamin C. Its effectiveness in cancer treatment remains, however, unproven. On this background, this first-ever randomized clinical trial aimed to explore the effects of intravenous vitamin C (IVC) on symptoms and adverse events associated with conventional breast cancer treatment.
This single-center, parallel-group, single-blind study was conducted in the oncology ward of a tertiary care hospital in Pakistan. After informed consent, breast cancer patients with Union for International Cancer Control stages IIA to IIIb were included in the study. Three hundred and fifty patients were randomized into two groups at a ratio of 1:1. The study group received 25 grams per week of IVC at a rate of 15 grams per hour for four weeks in addition to their current standard treatment, and the control group received a placebo in addition to their current standard treatment.
In patients who had received IVC, there were significant decreases in the severity scores after 28 days for the following symptoms:
- nausea, loss of appetite (2.26 ± 0.51 vs. 2.11 ± 0.52; p-value: 0.007),
- tumor pain (2.22 ± 0.45 vs. 1.99 ± 0.40, p-value: <0.0001),
- fatigue (3.11 ± 0.32 vs. 2.87 ± 0.29; p-value: <0.0001),
- insomnia (2.59 ± 0.35 vs. 2.32 ± 0.36, p-value: <0.0001).
The authors concluded that this study shows an improvement in the mean severity score of nausea, fatigue, tumor pain, loss of appetite, and fatigue. More studies are also needed to assess the long-term effects of IVC in the cancer management. This shall help incorporate the use of IVC in standard practice to make the journey of cancer management comfortable for the patients.
This new study does not stand alone. A 2014 review summarised three prospective studies as well as case reports and retrospective studies concluding that intravenous (IV) vitamin C alleviates a number of cancer- and chemotherapy-related symptoms, such as fatigue, insomnia, loss of appetite, nausea, and pain. Improvements in physical, role, cognitive, emotional, and social functioning, as well as an improvement in overall health, were also observed.
What about the mechanism of action? The authors of the new study offer the following explanation:
The role of vitamin C in reducing symptoms in cancer patients can be explained by its antioxidant properties. It is known that radiation and chemotherapy along with tumor cell metabolism increase oxidative stress in cancer patients. This stress is combated by the intrinsic antioxidants of the body including vitamin C. It is seen that patients with cancer have low levels of vitamin C in their bodies. This is because uncontrolled oxidative stress in cancer leads to high consumption of intrinsic body reserves resulting in vitamin C depletion. If not replenished duly, this deficiency eventually leads to the unopposed production of reactive oxygen species (ROS). The gut mucosa and the neural tissues, being the most sensitive to ROS, are affected the most. This leads to mucosal irritation of the gastrointestinal tract causing symptoms of nausea, vomiting, and loss of appetite. The neural irritation may trigger mental disorders including insomnia, tumor pain, and fatigue. Thus, replenishment of the intrinsic reserve by parenteral vitamin C administration may help combat the unopposed ROS production and play a vital role in alleviating cancer symptomatology, and hence QoL in these patients, as witnessed in our current study.
This explanation may be somewhat simplistic; moreover, the new study is far from flawless, and the totality of the evidence seems less than compelling. Nonetheless, the subject is, in my view, interesting and would seem to deserve further rigorous study.