1 Abstract

To date, a large number of facts have accumulated indicating the potential antitumor and antimetastatic effects of per oral sodium bicarbonate. Although the mechanisms of such activity remain unclear, it is logical to assume an effect on the tumor acidity. Tumor acidity affects every stage of cancer development. Therefore, the idea to change locally tumor microenvironment properties using sodium bicarbonate in an attempt to get an anticancer effect seems very attractive. For some manifestations of the tumor process, for example, for malignant ascites, the local use of sodium bicarbonate solution can be quickly transferred from preclinical studies to the clinic.\ Malignant ascites that occurs in the terminal stages of various cancer types significantly worsens the patient’s quality of life and is difficult to treat adequately. For most patients, paracentesis relieves symptoms but not leads to any survival benefits. In our study, we apply intraperitoneal perfusion procedure with sodium bicarbonate/sodium chloride solution in mice with Erlich ascites carcinoma. ICR (CD-1) mice were intraperitoneal injected with \(6 * 10^5\) (see Fig. 1.1) or \(12 * 10^5\) (see Fig. 1.2) Ehrlich carcinoma cells. At day 7 after tumor injection mice were intraperitoneal perfused with 0.9 % sodium chloride solution (SC) in group pH0 (n=14) or with 1 % sodium bicarbonate solution containing 0.9 % sodium chloride (SB) in group pH+ (n=14). Mice in control group (n=14) were intact. The perfusion procedure consisted of tumor ascites evacuation, double intraperitoneal administration of 10 ml SC or SB with 10 minutes incubation followed by evacuation, intraperitoneal washing with 0.9 % SC. Cell concentration in ascites and pH were measured. \ The ascites pH values were \(6.9 \pm 0.1\) in all groups. Cell concentrations at day of perfusion, on the 7th and 11th days after were around 100, 200 and 300 x 10ˆ6 cells per ml respectively in all groups but ascites volume was visually lower in pH+ group. Mice had median survival of 24 days in pH+ group, which was significantly different from median survival of 17 days in group pH0 and control (p<0.05). \ Sodium bicarbonate is effective treatment of mice with Erlich ascites carcinoma. We may suggest that intraperitoneal perfusion with sodium bicarbonate solution could be effective alternative to paracentesis or addition to HIPEC in palliative care of malignant ascites.

Survival analysis. The Kaplan-Meier curve shows the survival of the following three subgroups of animals ($6 * 10^5$ cell per mice).

Figure 1.1: Survival analysis. The Kaplan-Meier curve shows the survival of the following three subgroups of animals (\(6 * 10^5\) cell per mice).

Survival analysis. The Kaplan-Meier curve shows the survival of the following three subgroups of animals ($12 * 10^5$ cell per mice).

Figure 1.2: Survival analysis. The Kaplan-Meier curve shows the survival of the following three subgroups of animals (\(12 * 10^5\) cell per mice).