The disease itself is not only physical problem, but problem of the whole personality of a human, which consists not only of his body, but also of his mind and emotions. Emotional and intellectual conditions play significant role both in  susceptibility to all diseases, including cancer, and in ability to get rid of them.
Often cancer may be regarded as evidence that somewhere in life of a human there were unsolved problems, which became stronger and more complex due to series of stress situations during period from six to eighteen months before cancer appears.
Typical reaction of cancer patient to such problems and stress situations is a sensation of own helplessness and refusal to fight against them. Probably this emotional reaction activates a number of physiological processes suppressing natural protection mechanisms of an organism and creates conditions favorable for production of atypical calls.