Ayurvedic concept of Shatkriyakala: a traditional knowledge of cancer pathogenesis and therapy.

The term Kriyakala refers to the recognition of the stage of a disease's progress, which helps to determine appropriate measure to correct the imbalance in Doshas (biological factors). It is a compound expression, comprised of Kriya and Kala, where Kriya means the choice to treatment (medicine, food and daily-routine) used to improve the disturbance in Doshas, and Kala refers to the stage of progress of a disease. Sushruta, an ancient Indian surgeon, has described the concept of Kriyakala in Varnaprashnadhyaya, an ancient Vedic Sanskrit text, which seeks to explain the incidence of Varnas in terms of Doshic disturbances. Varna, in modern parlance, may be described as an inflammatory process that may lead ulceration and chronic inflammation, promoting all stages of carcinogenesis. Abnormal interactions between Prakriti (genotype) and environmental factors vitiate the Doshas and impair immunity, which can lead to aberrant cell growth and cancer. Moreover, the interaction between vitiated Doshas and weak Dhatus (body tissues) manifests as cancers of a specific organ. Shatkriyakala (six stages of progress of a disease), on the other hand, provides a framework to assess the cancer and its pathogenesis in different stages. According to Ayurvedic concepts, all cancer therapies treat the affected tissues indirectly by eliminating vitiated Doshas, rejuvenating Dhatus and restoring immunity in cancer patients. The present review describes the six stages of Shatkriyakala in detail, with an emphasis on research areas to validate the concept of Shatkriyakala. This traditional knowledge can be utilized with modern technologies to detect predisposition for cancer or diagnose cancer in its early stages.