According to the advantages and disadvantages of the clinical medical educa-tion of the ordinary specialized subject-to-undergraduate,the traditional teaching method has been improved in two aspects:choosing case and teaching process.It can be conformed that teaching method of case-based learning is very suitable for physiological teaching.It can improve the effective interaction of teachers and students,and enchance the students' abilities of self-study and theory with practice.

BACKGROUNDNeoadjuvant chemotherapy is one of the hot points of lung cancer therapy,which has been proven to be able to improve resection rate and 5-year survival of patients.But its effect on operation safety is not clear yet.The aim of this study is to confirm the effect of neoadjuvant chemotherapy on pulmonary arterial wall so as to assess its safety for operation in patients with lung cancer.

METHODSThirty-two patients underwent lobectomy or pneumonectomy with mediastinal lymphadenectomy after a neoadjuvant chemotherapy,compared with 36 patients surgically treated only.During the operation,the changes of thoracic structure were observed.After the operation,the pulmonary artery specimens were detected pathologically.

RESULTSThe incidence of pleural fibrosis and thickening of pulmonary arterial tunica adventitia in neoadjuvant chemotherapy group was significantly higher than those of control group(59.38% vs 22.22%,P < 0.01;68.75% vs 19.44%,P < 0.01).The incidence of tunica intima,internal elastic membrane and tunica media damage in neoadjuvant chemotherapy group was also markedly higher than those of control group(65.62% vs 33.33%,P < 0.01;59.38% vs 19.44%,P < 0.01;71.88% vs 22.22%,P < 0.01).

CONCLUSIONSNeoadjuvant chemotherapy may lead to pleural fibrosis and thickening of pulmonary arterial tunica adventitia and increase crispness of pulmonary arterial wall,which may increase difficulty and risk of operation.