In oncology trials, switching to the experimental treatment can occur in the control arm following disease progression and potentially impact overall survival (OS). It would be a clinically relevant question to estimate OS effect that would have been observed if there is no cross-over of treatment allowed. There are many literatures that provide sensitive approaches to adjust the cross-over effect, such as inverse probability of censoring weighting (IPCW) and rank preserving structural failure time (RPSFT). In this roundtable discussion, we will share the experiences about statistical approaches and practical experiences with several drugs.