Sodium bicarbonate, commonly known as baking soda, is widely used in the clinic as an antacid for treating gastric hyperacidity, among other conditions. Chao et al have reported a clinical trial about targeting intratumor lactic acidosis–transarterial chemoembolization. Based on conventional transarterial chemoembolization, the authors added a 5% sodium bicarbonate solution to cytotoxic drugs, resulting in a high local control rate. The explanation for the antitumor effects of sodium bicarbonate is related to acidosis in the tumor microenvironment. In this review, we summarize the findings from studies administering sodium bicarbonate alone or in combination with other anticancer therapies as cancer treatments, and discuss methods for safe and effective use of sodium bicarbonate in the clinic.
The acidic tumor microenvironment is so closely related to cancer development that strategies targeting this tumor hallmark may be a practical treatment. The utilization of sodium bicarbonate to neutralize the acidity and increase the tumor pHe might control cancer cells progression. Gatenby, Gillies, and colleagues have conducted several in vivo experiments to explore the anticancer effects of sodium bicarbonate (summarized in Table 1)
We propose that the research design of this clinical trial is worth some deep thinking. First, the trial used a unique mode to deliver sodium bicarbonate. Next, it took advantage of the coordinated effects of sodium bicarbonate and doxorubicin. Above all, this study gained a positive result largely due to its distinctive methods of evaluation, visible tumor residues (VTRs). VTRs are rarely used in traditional clinical research, the common endpoints of which are recurrence rate and overall survival. The investigators proposed that lower VTRs and better local control are independent prognostic factors for patient survival. Thus, even without overall survival results from the randomized clinical trial, they concluded that bicarbonate remarkably enhanced the anticancer activity of TACE.