TUMORE

TUMOR. — From *tumor* = swelling, better termed “neoplasm” (from the Greek “neoformation”), it is an atypical proliferation of elements of the body’s tissues, with autonomous development, incessantly progressive. The essential characteristic of these formations is their tendency to develop at the expense of the host organism, so much so that they may be considered true parasites.

This tendency, however, is not of the same intensity in all tumors, which, rather, according to the greater or lesser tendency toward this parasitism, are distinguished into benign tumors, with limited growth, lacking dissemination to other sites (metastasis) and recurrence after removal, and malignant tumors or “cancers,” endowed with particular aggressiveness toward the host organism and characterized by profound cellular atypia, such that they are biologically akin only to monstrosities. The atypia in malignant tumors is at once morphological (concerning the structure of individual cells in relation to one another) and biological-functional (the cells being endowed with a particular metabolism and functionality always different from the norm). Tumors must therefore be well differentiated from phenomena of hypertrophy (increase in cell volume without a simultaneous increase in their number) and hyperplasia (increase in the number of cells rather than their volume), inasmuch as such phenomena do not always possess a distinctly pathological character, but may be expressions of the body’s defense or compensation, while in their structure they always reproduce the morphological and functional characteristics of the mature cells of the organ or tissue involved. The tumor is not to be considered a purely dysplastic phenomenon (i.e., of anomalous transformation of tissue elements) either, being a neoformation rather than a dysplasia; nonetheless, it must be observed that the boundaries between these two phenomena are not absolutely clear and precise, especially with regard to benign tumors.

Despite numerous studies, even recent ones, aimed at clarifying the etiopathogenetic problem of tumors, it may be said that nothing precise is yet known either about the causes or about the mechanism of action of these causes themselves; hence, alongside a group of scientists who consider the tumor a disease of a single organ or tissue that only secondarily affects the entire organism, there are others who view the tumor phenomenon as a primary disease of the entire organism, manifesting in this or that organ through the direct action of particular, still unknown factors. Numerous theories have therefore been advanced to explain the genesis of tumors, among which should be recalled: Virchow’s irritative theory, the viral theory (i.e., from ultraviruses, which in recent times has gathered many supporters), Fichera’s oncogenic imbalance theory, Cohnheim-Durante’s theory of embryonic residues, Hansemann’s anaplasia theory, the hyperpostassemia theory, and the vital induction theory. The discovery of the possibility of inducing experimental cancers by exposing the organism to certain substances (dibenzopyrene) and the observation of occupational cancers (e.g., lung cancer in miners) or voluntary cancers (cancer of the lips or tongue in smokers) had led to the hope of having identified in this or that substance the element capable of determining the onset of tumors. Further studies, however, have moderated these early enthusiasms, especially because of the impossibility of clarifying the problem through the exclusive intervention of exogenous factors, and have led various authors to consider tumors as a disease due to particular predisposing genetic factors (the familial nature of cancer is well known), upon which the tumor would take root at a given moment in life, through the action of particular, still unidentified exogenous factors (chemical, physical, parasitic, viral, dietary). Thus arises the problem of the heredity of cancer. Only certain forms of tumor (e.g., glioma of the retina) appear frequently in the same family and demonstrate a notable heredity. In general, it is believed that even for other tumors, although there is no similar repetition of the disease in members of the same family, a predisposing “something” is nonetheless inherited; some authors thus speak even of a “neoplastic diathesis,” basing themselves chiefly on certain statistical considerations of undoubted importance: stomach cancer would be more common in Alpine and Nordic types (according to Niceforo and Pittard), while others (Benecke and Benedetti) have observed a certain predilection of tumors for paracentral individuals (normolinear, slightly macro- or microsplanchnic), with a certain antagonism between tuberculosis and tumors. A special humoral terrain proper to this diathesis is also indicated: the preneoplastic state or precancerous terrain, characterized by an increase in cholesterol in the blood and tissues, a relative alkalosis, and an inversion of the albumin-globulin ratio. N. Pende believes that certain temperaments (v.) are particularly predisposed to tumors (hyperthyroid parasympathicotonic, hyperthyroid in women).

It must also be recalled that the hypothesis of a certain heredity of cancer has found further confirmation in numerous studies conducted especially on mouse cancers. The most probable hypothesis is therefore that there exists some degree of familial predisposition to cancer, varying according to the family, sex, and affected organ.

From an epidemiological standpoint, it must be observed that no certain fact supports the contagiousness of cancer under ordinary living conditions. At one time, “cancer houses” were spoken of, but these are today excluded by almost everyone.

As for its spread, cancer must today be considered a ubiquitous disease that strikes every race and age, though it shows a certain predilection for old age (55–56 years). The WHO (World Health Organization) has recently declared that in recent years there has been an increase in mortality, especially from lung cancer. In Italy, recent statistics report that in 1944, 37,495 individuals died of cancer, while in 1950 the number of deaths rose to 49,607. Statistics conducted in recent years in Anglo-Saxon countries have shown that tumors are not rare even in childhood. In England from 1945 to 1947, there were 2,260 deaths from cancer among children under 15, making cancer the second leading cause of death after tuberculosis (with 6,075 deaths). In New York from 1942 to 1948, mortality from tumors in children exceeded that from any other cause.

The organs most frequently affected are the lung and stomach for males and the uterus and breast for females, but it may be said that no organ or system is absolutely immune to this disease, with the exception of the spleen, which, according to most authors, seems to possess oncological properties (i.e., capable of destroying cancerous elements) and thus does not allow the implantation and development of the neoplasm.

Given the multiplicity of organs involved, the variety in macroscopic and microscopic appearance, and the clinical course that this disease—so little understood in its intrinsic nature—may assume, it is natural that numerous classifications have been proposed, all of them more or less incomplete. In addition to the distinction between benign and malignant tumors, already mentioned above and based primarily on clinical course, tumors are classified as vegetating, plaque-like, and ulcerative according to their macroscopic appearance, while according to the tissue affected, there may be epithelial, glandular, connective, endothelial, nervous, muscular, and osseous tumors. The most precise and currently used classification, however, is the one that employs histological and embryogenetic criteria, based on the derivation of the cells of the various tumors from one or another of the embryonic germ layers. According to this classification, tumors are distinguished as follows: 1) ectodermal tumors, derived from the ectoderm proper; 2) mesodermal tumors, arising from the epithelia of the kidney, adrenal cortex, ovary, uterus, and prostate; from the endothelia of the serous membranes; from striated muscle fibers; 3) endodermal tumors, of the integumentary and glandular epithelia of the respiratory and digestive systems, tumors of the thymus and thyroid, and of the urinary bladder; 4) mesenchymal tumors, arising from connective support tissues, from blood-vascular tissues, from smooth muscle tissue, and from undifferentiated mesenchymal residues; 5) tumors from complex embryonic residues.

Currently, some systemic diseases affecting the blood and hemopoietic organs (leukemias, erythremias) are included in the broad category of tumors, being interpreted as tumors of the bone marrow. The diagnosis of the various tumor forms is extremely difficult, given the necessity that it be made at the very onset of the disease, when therapeutic measures still have a chance of being effective. Most malignant tumors, however—apart from those located on the skin and mucous membranes directly accessible to the human eye—display no characteristic clinical signs until they have reached such a stage of development and dissemination as to render all therapeutic aid useless. This fact has led physicians and specialists in the various institutions established by the state in all nations for the fight against tumors to identify and combat the so-called “precancerous states,” namely those chronic alterations with hyperplastic and dysplastic features, though not yet neoplastic, which often constitute the basis upon which a true tumor may later develop. Among these conditions are included some chronic suppurations, oral leukoplakia, gastric ulcers, polyps and warts, and cutaneous nevi. At the present time, however, a certain diagnosis of a more or less suspected tumor can be made only through biopsy, i.e., histological examination of a fragment of the suspected mass taken directly from the patient.

The problem of tumors cannot be considered resolved from a therapeutic standpoint. A report published by the National Institute of Bethesda (U.S.A.) and authored by Dyer states that by the end of 1948, more than 5,000 substances had already been tested with more or less negligible results in the fight against tumors. Current therapy is based primarily on: 1) physical and chemical means (X-ray or radium irradiation, iontophoresis, diathermy, electrophoresis, fulguration, electrocoagulation); 2) surgical means (early, radical, demolitive intervention, performed before the tumor has produced metastases); 3) medical treatment. In addition to standard palliative and symptomatic care aimed at alleviating the patient’s suffering and supporting the individual, various substances with cancerocidal and antimitotic action have recently been tested (nitrogen mustards, aminopterin, urethane, sodium cyanate, trypaflavin, atebrine), though with modest and mostly temporary results; attempts using organ lysates or stimulating the spleen with X-rays to produce antiblastic substances have likewise yielded no better outcomes.

At present, therefore, the problem of cancer must still be considered unresolved, despite some undeniable practical progress. A statistic by Smiles (U.S.A.) reports that the average survival rate of cancer patients has increased from 60 years (in 1920) to 64 years (in 1940). This fact is all the more significant when one considers that cancer strikes individuals over the age of 65 only in 0.83 per thousand cases.