 Enrolled stage 1B adenocarcinoma patient will be registered for the study and be randomly allocated to the treatment group and the observation group by the stratification factor; the institution. Each group is determined to have same number of study population. This study is open labeled and follow the permuted block design. Also the patients will be allocated by randomized table provided by a statistician. If it is converted to e-CRF, randomization of the patients will be performed by the automated computer program. 