[Studies on the appropriate frequency of the cervical cancer screening (author's transl)].

A total of 73,897 cases of women above 30 years old were screened for their cervical cancer by Pap smear in Niigata prefecture in 1978 and 1979. From them 37 cases of invasive cancer (0.05%) including a case of endometrial adenocarcinoma, stage II, 30 cases of carcinoma in situ (0.04%), and 52 cases of dysplasia (0.07%) were detected. From the correlation between the check up frequency of these patients and the cervical malignancy detected, the following were pointed out: 1) No invasive cancer but carcinoma in situ were detected from those patients who were cytoscreened by successive annual visits. 2) Stage Ia but not more advanced cervical cancer were detected from those patients who were screened at 2 years interval. 3) Stage Ib or farther advanced cervical cancer were detected from those patients who visited at 3 years or more years interval just like from those patients who visited for the first time. To detect cervical cancer in its preinvasive stage, annual Pap smear of adult women over 30 years old should be continued.