Commentary
Article
Patient Case Study: Use of Dietary Supplements in Patients With Breast Cancer
Even when safe, oral supplement use may not be appropriate to use during cancer treatment or recovery.
AT is a 38-year-old female who has stage 4 metastatic breast cancer that is positive for estrogen and progesterone receptor (ER+, PR+) and breast cancer gene (BRCA) 1/2 negative. She expressed concern to her pharmacist about using iron and multivitamin supplements for her breast cancer. She read an article about an observational study that linked the use of antioxidants such as vitamins A, C, and E; beta-carotenoids; coenzyme Q10 (CoQ10); and B12 with negative effects on breast cancer disease-free survival. She wondered whether she should continue taking the iron supplement and was looking for alternatives, such as a different brand of multivitamin.
AT takes ribociclib 600 mg daily from day 1 to 28; anastrozole 1 mg daily; olmesartan 20 mg daily; vitamin D3 2000 IU daily; ferrous sulfate 325 mg daily; and 1 adult multivitamin daily. Table 1 reviews her laboratory results.
Table. AT's Laboratory Results
Discussion
Breast cancer primarily occurs in middle-aged and older women. The median age at the time of breast cancer diagnosis is 62. Overall, the average risk of a woman in the US developing breast cancer sometime in her life is approximately 13%, meaning there is a 1 in 8 chance a woman will develop breast cancer.1
Early detection of breast cancer is key to survival, with a 93% or higher survival rate in the first 5 years. Annual mammography is the standard screening tool recommended for women 40 years of age and older. Additionally, women with a family history of breast cancer, known BRCA1 and BRCA2 gene mutations, and other pertinent risk factors are advised to undergo breast MRI once a year.1
Dietary supplementation, including minerals and multivitamins, is often taken by cancer patients, including those with breast cancer.2 Some dietary supplements, such as lutein and vitamins A, C, and E, are classified as antioxidants, meaning they inhibit oxidation and reduce free radicals in the body, which some researchers have demonstrated to help optimize chemotherapy and improve breast cancer outcomes.3
However, there are studies suggesting that some dietary supplements might dampen the efficacy of the cytotoxic drugs. For example, in vitro studies have shown upregulation of glucose transporters that carry oxidized dehydroascorbic acid in cancer cells. Hence, they absorb more glucose and vitamin C than normal cells.4 A study by Lesperance et al. examined 90 patients with breast cancer taking megadoses of multivitamins, minerals, or antioxidants irrespective of their treatment protocol. The overall survival at 5 years was 72% for the supplement group and 81% for the control group.5 However, results of the statistical analysis indicated that there was no difference between the 2 groups in breast cancer-specific survival (BCSS) or disease-free survival (DFS).5
The study AT saw is the Diet, Exercise, Lifestyle, and Cancer Prognosis (DELCaP) study. DELCaP was an observational, prospective phase 3 trial performed in a high-risk early-stage breast cancer population. Patients with breast cancer were randomly assigned to different treatment schedules with doxorubicin, cyclophosphamide, and paclitaxel. Participants were given questionnaires about their use of dietary supplements at baseline and again 6 months after treatment completion. The primary goal of the study was to determine whether certain antioxidant supplements influenced survival outcomes. The study looked at vitamins A, C, and E; carotenoids; and CoQ10.3
Patients are bound to feel helpless and thus turn to their pharmacists | Image credit: Farknot Architect | stock.adobe.com
The trial results found that except for the participants who reported taking a multivitamin, there was a 41% increase in hazard of breast cancer recurrence with the use of any antioxidant supplementation when used before and during chemotherapy treatment.3 The association was not statistically significant, and there was a similar but weaker association with mortality.3 These findings are consistent with ongoing concerns that the use of antioxidants before and during chemotherapy can reduce its cytotoxic effects and should not be taken during cancer treatment. The trial results also found that vitamin B12 and iron supplementation before and during chemotherapy were also associated with breast cancer recurrence and mortality.3
There were several potential confounding factors with the study, such as patient selection, patient recall, and potential patient underreporting of supplements. The biochemical impact of antioxidants and how they negate the effect of chemotherapy agents or fuel the tumor cells is yet to be fully studied. The authors cautioned that a larger randomized controlled clinical trial with cancer patients who were taking antioxidants versus not taking antioxidants is needed to establish a connection. However, providers should exercise caution among cancer patients when considering supplements, apart from multivitamin, during chemotherapy.3
Managing Anemia
Although the DELCaP study found that iron supplementation before and during chemotherapy was associated with breast cancer recurrence and mortality, it is important to emphasize that anemia in cancer patients should be treated. Anemia is a common concurrent risk factor in breast cancer patients, who are routinely prescribed OTC iron. Patients should be directed to consult their providers for treatment of anemia. Untreated anemia can have a negative effect on relapse, metastasis, and death. It has been postulated that anemia can induce tumor hypoxia, angiogenesis, and resistance to conventional oncolytic and radiotherapy via the VEGF axis.6
A retrospective study conducted by Zhang et al. showed significantly higher mortality in preoperative patients with anemia versus nonanemic patients who underwent surgery related to their breast cancer.7 Furthermore, after analyzing 336 women with early-stage breast cancer, Kandemir et al. found that disease-free and overall survival were shorter in patients with anemia at the time of diagnosis than in patients with normal hemoglobin level, defined as greater than or equal to 12 g/dl. All these studies emphasize the importance of a baseline or corrected hemoglobin level in breast cancer patients with curative intent.6-8
Conclusion
In the face of conflicting data, patients are bound to feel helpless and thus turn to their pharmacists, who are well-positioned to make the best recommendation using evidence-based medicine. Due to the increased risk of recurrence and death observed with iron supplementation, considering AT’s normal ferritin and iron levels, the patient was asked to consult with the provider about whether she should continue taking her iron supplement. Also based on existing evidence, AT can continue to take her multivitamin, but she should contact her provider if she wishes to begin any new OTC supplements.
