Treatment.—­Removal by surgical means affords the best prospect of cure.  If carcinomatous disease is to be rooted out, its mode of spread by means of the lymph vessels must be borne in mind, and as this occurs at an early stage, and is not evident on examination, a wide area must be included in the operation.  The organ from which the original growth springs should, if practicable, be altogether removed, because its lymph vessels generally communicate freely with each other, and secondary deposits have probably already taken place in various parts of it.  In addition, the nearest chain of lymph glands must also be removed, even though they may not be noticeably enlarged, and in some cases—­in cancer of the breast, for example—­the intervening lymph vessels should be removed at the same time.

The treatment of cancer by other than operative methods has received a great deal of attention within recent years, and many agents have been put to the test, e.g. colloidal suspensions of selenium, but without any positive results.  Most benefit has resulted from the use of radium and of the X-rays, and one or other should be employed as a routine measure after every operation for cancer.

It has been demonstrated that cancer cells are more sensitive to radium and to the Rontgen rays than the normal cells of the body, and are more easily killed.  The effect varies a good deal with the nature and seat of the tumour.  In rodent cancers of the skin, for example, both radium and X-ray treatment are very successful, and are to be preferred to operation because they yield a better cosmetic result.  While small epitheliomas of the skin may be cured by means of the rays, they are not so amenable as rodent cancers.

Cancers of mucous membranes are less amenable to ray treatment because they are less circumscribed and are difficult of access.  In cancers under the skin, the Rontgen rays are less efficient; if radium is employed, the tube containing it should be inserted into the substance of the tumour after the method described in connection with sarcoma—­and another tube should be placed on the overlying skin.

In the employment of X-rays and of radium in the treatment of cancer, experience is required, not only to obtain the maximum effect of the rays, but to avoid damage to the adjacent and overlying tissues.

Ray treatment is not to be looked upon as a rival but as a powerful supplement to the operative treatment of cancer.

VARIETIES OF CANCER

The varieties of cancer are distinguished according to the character and arrangement of the epithelial cells.

The squamous epithelial cancer or epithelioma originates from a surface covered by squamous epithelium, such as the skin, or the mucous membrane of the mouth, gullet, or larynx.  The cancer cells retain the characters of squamous epithelium, and, being confined within the lymph spaces of the sub-epithelial connective tissue, become compressed and undergo a horny change.  This results in the formation of concentrically laminated masses known as cell nests.