Magnetic resonance imaging shows (MRI) that cancers are acidic. This acidity has been shown to increase tumor cell metastases, growth, and invasiveness. An acidic environment leads to toxicity and apoptosis (natural cell death) for normal cells. An acidic pH promotes angiogenesis (growth of new blood vessels.) The result is an area of dead and dying tissues around the tumor, allowing the tumor to grow.
Correction of tumor acidity can block the growth of some cancers. Sodium bicarbonate (baking soda) is a physiologic buffer against acidity. The combination of bicarbonate and a hydrogen ion becomes carbon dioxide (CO2) and water. Bicarbonate levels are low in tumors because the excess amount of hydrogen ions uses up the available bicarbonate. CO2 levels are high and oxygen levels are low in tumors. This can be determined by MRI.
The goal of this study was to test various buffer systems to see which works best for alkalinization of tumors in a computer model of cancer. A three dimensional model of a tumor was used. The ways that tumor cells behave were simulated. This technique can reveal the effects of tumor growth and therapy. The authors wanted to study the ability of bicarbonate therapy to delay the development of metastases in this computer model and to delay tumors from becoming clinically apparent.
The authors used the parameters that tumor cells will die at a pH of 6.4 and that normal cells will die at a pH below 6.8. Aerobic glucose metabolism was increased in the model. The computer model was carefully designed to accurately duplicate the movement of the chemical components in and out of the cells. The model was found to be accurate. The carbon dioxide levels were quite high in cells distant from blood vessels. The extracellular pH was lowest in parts of the tumors most distant from the blood vessels.
In the model, bicarbonate buffers were added at three concentrations to evaluate the ways they altered pH of tumors. The highest dose was equal to 70 g/d of NaHCO3.
The authors used the simulation to evaluate the characteristics of an ideal buffer. A buffer that would diffuse into the tissue faster than bicarbonate would work better to increase the extracellular pH. The alteration of diffusion rates did not alter the pH as much as altered pKa (dissociation constant) did. A pKa of about 7 seems to be ideal.
The high bicarbonate group received 40 g NaHCO3, daily. In this computer model, tumor invasion was blocked, completely by the bicarbonate. Tumor cells died with the bicarbonate treatment. Normal cells were not changed by the bicarbonate.
The authors report that the treatment is not alkalization but is, actually, “treatment with physiologic buffer.” A physiologic buffer drives the whole system toward a normal pH (7.35-7.45). Tissues with a normal pH will not be changed, only areas will be changed which have an abnormal pH (acid or alkaline.)
High lactic acid levels in tumors result in a poor prognosis.
CONCLUSION: Three-dimensional mathematical modeling was used to evaluate bicarbonate treatment of tumor acidity. Clinical doses of bicarbonate can block tumor growth by reducing tumor pH and causing tumor death without changing blood pH. This may be useful, clinically. pH buffers may be a novel cancer therapy.
NOTE: pKa is the ‘acid dissociation constant.’ It is a measure of the strength of an acid. A good buffer system is a weak acid and it’s salt.
Read about the use of pH buffers and the regulation of cancer growth.
Attention must be paid to the amount of sodium in 40 grams daily of baking soda and the association of high sodium intake with hypertension.