Effect of timing of surgery on survival after preoperative hyperfractionated accelerated radiotherapy (HART) for locally advanced rectal cancer (LARC): Is it a matter of days?

We intend to analyse retrospectively whether the time interval ("gap duration'' = GD) between preoperative radiotherapy and surgery in locally advanced rectal cancer ( LARC) has an impact on overall survival ( OS), cancer specific survival (CSS), disease free survival (DFS) and local control (LC). Two hundred seventy nine patients with LARC were entered in Trial 93-01 (hyperfractionated accelerated radiotherapy 41.6 Gy/26 Fx BID) shortly followed by surgery. From these 250 patients are fully assessable. The median GD of 5 days was used as a discriminator. The median follow-up for all patients was 39 months. GD > 5 days was a significant discriminator for actuarial 5-years OS (69% vs 47%, p = 0.002), CSS ( 82% vs 57%, p = 0.0007), DFS (62% vs 41%, p = 0.0003) but not for LC ( 93% vs 90%, p = non-significant). In multivariate analysis, the following factors independently predict outcome; for OS: age, GD, circumferential margin ( CM) and nodal stage (ypN); for CSS: GD, ypN and vascular invasion (VI); for DFS: CEA, distance to anal verge, GD, ypN and VI; for LC: CM only. Gap duration predicts survival outcome but not local control. The patients submitted to surgery after a median delay of more than 5 days had a significantly better outcome.