A neoplasm is a group of new cells which are growing without control and afford no benefit. These are called therefore neoplasms (new- growths). The terms tumor and neoplasm are for practical purposes synonymous.
Normal growth in the body continues under the control of natural body forces until maturity of the part is reached. Thereafter, growth takes place only to replace worn-out or injured tissues. Neoplasms arise when a group of cells begin to grow wildly and disorderly. There is no control of the growth by the natural forces which normally control cell reproduction. The area of new growth forces its way among the normal cells in the body without respect to their importance to life and comfort.
Cause of Neoplasms
The etiology (cause) of this abnormal, uncontrolled growth of cells is unknown. At the present time there are many research programs in operation which are investigating all phases of neoplastic processes. From these, it would at present appear that there is no single definite cause of neoplasms. Various investigative approaches have included the study of many different chemical substances, hormones, germs, and mechanical agents. As yet, no solitary cause has been ascertained.
Many new formations occur in the body which are not true tumors, such as the overgrowth of bone around a fracture site, the normal enlargements of the breasts and womb with pregnancies and menstrual periods, swellings from inflammatory processes, and the normal thickening of the skin with callus formation from manual labor. These are not true tumors, for their growth is governed by the natural body- controlling forces. It is probable that other conditions now thought to be true neoplasms will be recognized as due to some definite cause.
Neoplasms may develop in any tissue or organ, but it is thought that before a tumor actually appears in a tissue, that tissue had some previous abnormality. This is strongly suggested by the close relationship between an area where there has been continued irritation of the tissues and the appearance of a tumor at that site. Tumors of the lip occur more often in heavy smokers; tumors of the mouth arise in areas where ill- fitting dentures have irritated the gums and cheeks; tumors of the outlet of the womb are more frequent in cases where there have been unrepaired lacerations from childbirth; neoplasms in areas of chronic inflammation are occasional; and skin tumors are more frequent in exposed areas. Numerous other examples suggest that chronic irritation plays a role in the development and progression of tumors.
Neoplasms are not due to any known germ; i.e., are neither infectious nor contagious. They are not thought to be related to any infectious disease. The most intimate contacts with patients suffering from tumors will not transmit the disease. Immunity to tumors cannot be developed in any way known. A person with an infectious disease may develop a tumor but is no more likely to than a normal person.
Neoplasms are thought not to be due to injuries. In some cases it would appear that a solitary bruise of a bone or a breast has initiated a neoplasm. But it is more likely that the injury has merely directed the patient’s attention to the site. The medical profession believes that a single injury to a tissue will not cause a tumor to develop. It is more likely a matter of coincidence.
There is no known relationship between foods, combination of foods, or eating habits, and the development of tumors. There is no evidence that the temperature of foods or beverages plays any role in tumor etiology. The use of alcohol bears no known relationship to neoplasms. The general state of health of an individual does not seem to influence the appearance of tumors. There is no greater frequency of neoplastic disease in people who are chronically ill with some other disease, are malnourished, have vitamin deficiencies, are above or under normal weight, or are anemic.
There do appear, however, to be certain predispositions to tumors. There is a slight family tendency, which seems to be beyond the laws of chance. Statistical studies show that when certain tumors have occurred in parents or grandparents, there is a slight, but only a slight, increase in the incidence among their progeny. This familial propensity has not been explained satisfactorily. There is also a statistical difference in the frequency of neoplasms between the two sexes. In organs common to both, there is a greater frequency of neoplasms of all types and of all organs in males than in females, with only one or two exceptions. This again is only a minor and an almost insignificant disproportion. Among races there is a slightly greater proportion of neoplastic diseases among the White than the Negro population. Tumors may occur in any person at any time, however, so these predispositions are not of major significance.