My thoughts: While high dose vitamin C injections may be very helpful in reducing inflammation, improving quality of life and induce cancer cell death they may also increase the risk of cardiovascular events and should be done after an cardiovascular evaluation (at least by blood lipid testing) by a doctor trained in IV vitamin C administration. They may also be administered with chemotherapy.
High-dose vitamin C (≥10 mM) significantly decreased cell viability of all breast cancer cell lines, particularly of MCF-7 cells. The catalase activities of MCF7 and MDA-MD-231 cells were also lower than those of MCF10A cells. Moreover, cell viability of both MCF7 and MDA-MD-231 cells was decreased further when combining high-dose vitamin C and eribulin mesylate."
MDA-MD-231 cells don't have estrogen, progesterone or HER2 receptors so a good model for TNBC.
This is on ovarian cancer but it's the same concept:
The combination of parenteral ascorbate with the conventional chemotherapeutic agents carboplatin and paclitaxel synergistically inhibited ovarian cancer in mouse models and reduced chemotherapy-associated toxicity in patients with ovarian cancer. On the basis of its potential benefit and minimal toxicity, examination of intravenous ascorbate in combination with standard chemotherapy is justified in larger clinical trials."
"Vitamin C expands the therapeutic window of BETi by sensitizing TNBC to BETi. Using vitamin C as a co-treatment, lower doses of BETi could be used to achieve an increased therapeutic index in patients, which will translate to a reduced side effect profile."
"A variety of laboratory studies suggest that, at high concentrations, ascorbate does not interfere with chemotherapy or irradiation and may enhance efficacy in some situations (Fujita, et al., 1982; Okunieff & Suit, 1987; Kurbacher, et al., 1996; Taper, et al., 1996; Fromberg, et al., 2011; Shinozaki, et al., 2011; Espey, et al., 2011). This is supported by meta-analyses of clinical studies involving cancer and vitamins; these studies conclude that antioxidant supplementation does not interfere with the toxicity of chemotherapeutic regiments (Simone, et al., 2007; Block, et al., 2008)."
A 60 year old woman with stage IIIC adenocarcinoma of the ovary and an initial CA-125 of 81 underwent surgery followed by six cycles of chemotherapy (paclitaxel, carboplatin) with oral antioxidants. After six cycles of chemotherapy, patient began parenteral ascorbate infusions. Ascorbate infusion began at 15 grams once weekly and increased to 60 grams twice weekly. Plasma ascorbate levels above 200 mg/dL were achieved during infusion. Treatment continued to date of publication. The patient supplemented with vitamin E, coenzyme Q10, vitamin C, beta-carotene, and vitamin A. Her CA-125 levels normalized after one course of chemotherapy. After the first cycle of chemotherapy, the patient was noted to have residual disease in the pelvis. At this point, she opted for intravenous ascorbate. Thirty months later, patient showed no evidence of recurrent disease and her CA-125 levels remained normal.
A 55 year old woman with stage IIIC papillary adenocarcinoma of the ovary and an initial CA-125 of 999 underwent surgery followed by six cycles of chemotherapy (paclitaxel, carboplatin) combined with oral and parenteral ascorbate. Ascorbate infusion began at 15 grams twice weekly and increased to 60 grams twice weekly. Plasma ascorbate levels above 200 mg/dL were achieved during infusion. After six weeks, ascorbate treatment continued for one year, after which patient reduced infusions to once every two weeks. The patient also supplemented with vitamin E, coenzyme Q10, vitamin C, beta-carotene, and vitamin A. At the time of publication, she was over 40 months from initial diagnosis and remained on ascorbate infusions. All CT and PET scans were negative for disease, and her CA-125 levels remained normal (Drisko, et al., 2003).