Cancer patients will face different kinds of mental distress based on different types of cancer condition. From slow-growing cancer patients to fast-growing cancer patients, they all shows different levels of ego defensiveness, anxiety, depression, self-criticism and even guilt. All types of depressive emotions frequently appear among cancer patients and will further motivate the progression in tumour in cancer patients. In other words, psychosomatic mechanisms have a direct relationship with tumour progression.

A number of animal studies have shown that the neurologic apparatus between the central process and the tissue will directly affect tumour growth. In dogs, Petrova (1946) found that repeated overloads of the nervous system produced by traumatic stimuli created ‘spontaneous’ tumor formation. In rabbits, the use of sodium amytal and other CNS-inhibitory drugs resulted in faster development of grafted tumours and earlier death, whereas caffeine and other CNS stimulants blocked and delayed tumour development. In pigs, Stein found that the destruction of zones in the anterior hypothalamus resulted in decreased titters of antibody as well as in inhibited and delayed hypersensitivity reactions by changing the cortex or the hypothalamus through immunologic responses which can reduce the animal’s resistance to malignant tumours. Korneva found that the destruction of dorsal hypothalamus resulted in longer survival of the tumour implant by weakening the primary antibody reaction and extended the presence of antigen in blood.

There is also a endocrinologic connection with tumour progression by affecting the immune system. Hormones such as techolamines, thyroid, growth hormones in a cyclic interplay places a part in tumour genesis which either inhibit or stimulate the immune reaction and thus influence the growth of tumour. The immune system is affected by different hormones. In the afferent phase of immune system, a modest increase in steroid production will stimulates macrophage activity whereas substantial increases in steroid production inhibit the activity of macrophages. When macrophages fail, tumour growth often extends and cannot be controlled by other sections of the immune system. This shows that mild stress is helpful in resisting tumour growth whereas intensive stress and breakdown of defence will cause the tumour growth to extend. Interferon production by infected cells, white blood cells, and macrophages is affected by stress factors. Solomon concluded that the changes in interferon production depend on the total stress situation which varies by species by giving electric shock. Stress will increase steroid production which decreased antibody reaction.

Stress factors, mediated through endocrinologic as well as nervous system channels provide an input to the immunologic system and build up the bridge between stress and cancer.

 

BY ROSIE XU