title: Pathologic response to neoadjuvant treatment in locally advanced rectal cancer and impact on outcome.
abstract: BACKGROUND
  Downstaging and pathologic complete response (pCR) after chemoradiotherapy (CRT) may improve progression-free survival and overall survival (OS) after curative therapy of locally advanced adenocarcinoma of rectum. The purpose of this study is to evaluate the pathologic response subsequent to neoadjuvant chemoradiation in locally advanced rectal adenocarcinoma and any impact of response on oncological outcome [disease-free survival (DFS), OS].
  
  
  METHODS
  A total of 127 patients with histologically-proven rectal adenocarcinoma, locally advanced, were treated with preoperative radiotherapy and concurrent 5-fluorouracil (5 FU), and followed by curative surgery. Pathologic response to neoadjuvant treatment was evaluated by comparing pathologic TN (tumour and nodal) staging (yp) with pre-treatment clinical staging. DFS and OS were compared in patients with: pCR, partial pathologic response and no response to neoadjuvant therapy.
  
  
  RESULTS
  14.96% (19 patients) had a pCR, 58.27% [74] showed downstaging and 26.77% [34] had no change in staging. At follow-up (range, 4-9 years, median 6 years 2 months or 74 months), 17.32% [22] showed recurrence: 15.74% [20] distant metastasis, 1.57% [2] pelvic failure. 10.5% [2] of the patients with pCR showed distant metastasis, none showed local recurrence. In the downstaged group, nine developed distant failure and two had local recurrence (14.86%). Distant failure was seen in 26.47% [9] of those with no response to neoadjuvant treatment. DFS and OS rates for all groups were 82.67% and 88.97% respectively. Patients with pCR showed 89.47% DFS and 94.7% OS. In partial responders, DFS was 85.1% and OS was 90.5%. In non-responders, DFS and OS were 73.5% and 82.3% respectively. Patients with pCR had a significantly greater probability of DFS and OS than non-responders. Rectal cancer-related death was 11.02% [14]: one patient (5.26%) with pCR, 9.47% [7] in the downstaged group and 17.64% [6] of non-responders.
  
  
  CONCLUSIONS
  The majority of patients showed some response to neoadjuvant treatment. Findings of this study indicate tumour response to neoadjuvant CRT improves the long-term outcome, with a better result in patients with pCR.
authors: William Buckland Radiotherapy Centre, Alfred Hospital, 55 Commercial Road, Melbourne, Victoria 3004, Australia ;
authors: Mahshid
authors: M
authors: Jalilian
authors: William Buckland Radiotherapy Centre, Alfred Hospital, 55 Commercial Road, Melbourne, Victoria 3004, Australia ;
authors: Sidney
authors: S
authors: Davis
authors: Biostatistics Unit, Faculty of Health, Deakin University, Burwood Highway, Burwood, Victoria 3125, Australia ;
authors: Mohammadreza
authors: M
authors: Mohebbi
authors: William Buckland Radiotherapy Centre, Alfred Hospital, 55 Commercial Road, Melbourne, Victoria 3004, Australia ;
authors: Bhuvana
authors: B
authors: Sugamaran
authors: William Buckland Radiotherapy Centre, Alfred Hospital, 55 Commercial Road, Melbourne, Victoria 3004, Australia ;
authors: Ian W
authors: IW
authors: Porter
authors: Department of Colorectal Surgery, Alfred hospital, 55 Commercial Road, Melbourne, Victoria 3004, Australia.
authors: Stephen
authors: S
authors: Bell
authors: Department of Colorectal Surgery, Alfred hospital, 55 Commercial Road, Melbourne, Victoria 3004, Australia.
authors: Satish K
authors: SK
authors: Warrier
authors: Department of Colorectal Surgery, Alfred hospital, 55 Commercial Road, Melbourne, Victoria 3004, Australia.
authors: Roger
authors: R
authors: Wale
keywords: Rectal cancer; chemoradiotherapy (CRT); histopathology response; outcome