[QUESTIONNAIRE SURVEY ON CLINICAL T CATEGORY OF PROSTATE CANCER FOR CLINICAL PHYSICIANS]

According to the 5th edition of the Japanese General Rule for Clinical and Pathological Studies on Prostate Cancer, clinical T2c is defined as"a tumor involving both lobes". It is not defined whether this refers only to continuous lesions spreading across both lobes or also includes small, non-continuous lesions present in both lobes. Furthermore, the General Rule stated that"it is generally understood that pathological findings from biopsies are not taken into consideration when determining T categories". We investigated how physicians interpret the General Rule and perform T classification in real-world clinical practice. We prepared five hypothetical cases with negative digital rectal examination findings but with lesions identified on magnetic resonance imaging (MRI) and conducted a questionnaire survey targeting board-certified urologists certified by the Japanese Urological Association. We received responses from 58 participants. Twenty-six participants (44.8%) diagnosed cases with discontinuous lesions in both lobes as cT2a, and 32 participants (55.2%) diagnosed them as cT2c. In addition, 41 participants (70.7%) diagnosed cases in which lesions were found in one lobe on MRI and cancer was detected in both lobes by biopsies as cT2a, while 17 participants (29.3%) diagnosed them as cT2c. Furthermore, three participants (5.2%) diagnosed cases in which cancer was detected by biopsies only from the contralateral side where lesions were found on MRI as cT1c, 49 participants (84.5%) diagnosed them as cT2a, and six participants (10.3%) diagnosed them as cT2c. In staging prostate cancer, the General Rule can have multiple meanings and there are cases in which even specialists disagree. Since T classification affects treatment strategies, it is desirable to have a uniform understanding based on a clear definition.