[Morphological characteristics of the phase and staging in cancer development].

According to the biopsy (10000 tumors) and autopsy materials cancer in its development occurs in the following stages: background lesions, precancer, preinvasive cancer (Ca in situ) and invasive cancer. Background lesions contribute to and precede the development of cancer, the former are associated with the proliferation of epithelial cells with their preserved differentiation. In precancer--excessive proliferation of epithelial cells with the formation of papillary outgrowths, pseudomultistratified cells without their anaplasia. Preinvasive cancer (Ca in situ) is referred to as a zero stage of cancer (according to WHO classification). Background lesions in 10-20% progress to cancer, precancer in 20-30%--to preinvasive cancer (Ca in situ), and preinvasive cancer develops into invasive cancer in 30-60% of cases. With background [corrected] lesions cancer is noted in 2-3%, in precancer--in 3-6%. An early diagnosis of cancer is possible with the recognition of preinvasive cancer (Ca in situ) and microinvasive cancer, yielding most favourable clinical issues.