From a thermodynamic point of view, living cell life is no more than a cyclic process. It starts with the newly separated daughter cells and restarts when the next generations grow as free entities. In this cycle the cell changes its entropy. In cancer the growth control is damaged. In this paper we analyze the role of the volume-area ratio in cell in relation to the heat exchange between cell and its environment in order to point out the effect on the cancer growth. The result holds to a possible control of the cancer growth based on the heat exchanged by the cancer towards its environment, and the membrane potential variation, with the consequence of controlling the ions fluxes and the related biochemical reactions. This second law approach could represent a starting point for a possible future support for the anticancer therapies, in order to improve their effectiveness for the untreatable cancers.