[Precancerous conditions of the oral cavity. Note I. General considerations. Critical review of the literature].

The authors deal with the current topic of precancerous states of the oral cavity, considering various aspects such as etiopathology, diagnosis, the clinical picture and therefore, nosological classifications. The region of the Air Passages and Superior Digestive Tract (APSDT) should be considered as a single system and it is affected by a set of genetic and environmental conditions common to the various anatomical regions of which it consists. The significance of several irritating agents, which are also habitually used (e.g. tobacco), has been demonstrated for some time, whereas, the actual harmful effects of other factors such as immunodepression in particular, are only now being evaluated and detected. The discussion concerning precancerous lesions of the oral cavity, should actually refer to lesions that do not present the histologic, biological and clinical characteristics of malignant neoplasms, but that have the objective possibility of developing them. Some lesions that traditionally belong to this pathological grouping often present dysplastic aspects, if not the actual characteristics of "carcinoma in situ". Therefore, the availability of a set of indexes is of primary importance and it should be capable of providing an orientation for diagnosis and clinical practices in a precise, standardized manner. The authors hold these indexes to be divisible into three groups as follows. The first group is composed of the "parameters of cellular kinetics" and includes the percentage of cells in phase S (LI), phase S time (Ts), cell cycle duration (Tc), and the growth fraction (GF). The second group consists in the "parameters of cellular morphology", including the nuclear content in DNA, the value of the nuclear surface and the ploidy. The third group is more specific for the existence of a pathologic mass. However, given the uncertainties of the borderlines traditionally attributed to precancerous pathology, this group is definitely useful. It is composed of the potential doubling time (Tpot) and the tumor volume doubling time (Td). Moreover, biopsy is held to be an indispensable tool and the procedure should be conducted in the various manners possible according to well-defined conditions. A correct evaluation of these parameters allows for a correct approach to precancerous pathology and the prevention of the clinical risks of "rapid proliferation" even in the diagnostic biopsy phase.