Present situation of pTNM classification in Japan: questionnaire survey of the pathologists of Gan-shinryo-renkei-kyoten Byoin (local core cancer hospitals) on pTNM classification.

pTNM classification is the most important element of surgical pathology. Internationally, the International Union against Cancer (UICC)-TNM is the standard TNM classification. In the present study questionnaires about the pTNM were sent to the pathology divisions of 288 institutions designated as Gan-shinryo-renkei-kyoten Byoin (local core cancer hospitals) on the basis of the Cancer Control Act. The questionnaire consisted mainly of questions about the TNM. There were 78 respondents, including 70 qualified pathology specialists, with a mean of 18.4 years of experience. The recognition rate of the important basic rules of the UICC-TNM were as follows: 'When in doubt, select the lower': 63.6% (49/77); 'Direct invasion to a lymph node is an N component': 61.0% (47/77); 'Only the extension of an invasive cancer is a T component': 45.5% (35/77). Few respondents knew the UICC criteria for judging whether multiple pulmonary lesions represent metastatic or multiple primary lesions. Only 26 (36.4%) of 77 pathologists were informed about cTNM routinely, suggesting that neither pathologists nor clinicians possess adequate knowledge about pTNM classification in many institutions. It is recommended that pathologists be informed about the rules and importance of pTNM through education, the revised Japanese classification of cancers, and self-assessment of their own institutes.