Evaluation of Tumor Response after Short-Course Radiotherapy and Delayed Surgery for Rectal Cancer.

Daniela Rega,Fabiana Tatangelo,Luigi Aloj,Antonio Avallone,Ugo Pace,Paolo Delrio,Antonella Petrillo,Biagio Pecori,Dario Scala,José A Morgado-Díaz

doi:10.1371/journal.pone.0160732

Daniela Rega, Fabiana Tatangelo + Show 8 more

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https://doi.org/10.1371/journal.pone.0160732

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Abstract

PurposeNeoadjuvant therapy is able to reduce local recurrence in rectal cancer. Immediate surgery after short course radiotherapy allows only for minimal downstaging. We investigated the effect of delayed surgery after short-course radiotherapy at different time intervals before surgery, in patients affected by rectal cancer.MethodsFrom January 2003 to December 2013 sixty-seven patients with the following characteristics have been selected: clinical (c) stage T3N0 ≤ 12 cm from the anal verge and with circumferential resection margin > 5 mm (by magnetic resonance imaging); cT2, any N, < 5 cm from anal verge; and patients facing tumors with enlarged nodes and/or CRM+ve who resulted unfit for chemo-radiation, were also included. Patients underwent preoperative short-course radiotherapy with different interval to surgery were divided in three groups: A (within 6 weeks), B (between 6 and 8 weeks) and C (after more than 8 weeks). Hystopatolgical response to radiotherapy was measured by Mandard’s modified tumor regression grade (TRG).ResultsAll patients completed the scheduled treatment. Sixty-six patients underwent surgery. Fifty-three of which (80.3%) received a sphincter saving procedure. Downstaging occurred in 41 cases (62.1%). The analysis of subgroups showed an increasing prevalence of TRG 1–2 prolonging the interval to surgery (group A—16.7%, group B—36.8% and 54.3% in group C; p value 0.023).ConclusionsPreoperative short-course radiotherapy is able to downstage rectal cancer if surgery is delayed. A higher rate of TRG 1–2 can be obtained if interval to surgery is prolonged to more than 8 weeks.

Highlights

Preoperative long course radiotherapy has been shown to be effective in downsizing locally advanced rectal tumors [1,2,3]
A higher rate of Tumor regression grade (TRG) 1–2 can be obtained if interval to surgery is prolonged to more than 8 weeks
Long-course chemo-radiation has been extensively applied and encouraging results derive from this approach in terms of local control with a high rate of tumor regression up to a significant rate of complete response

Summary

Introduction

Preoperative long course radiotherapy has been shown to be effective in downsizing locally advanced rectal tumors [1,2,3]. “sterilizing” the irradiated area immediately before surgery without any expected on the tumor’s stage and size This is mainly due to the short overall treatment time (OTT) in patients operated on in the week following the end of the radiotherapy. The increase of the OTT (by prolonging the interval between radiation and surgery) could raise the rate of tumor regression and induce a higher rate of complete response even in patients treated with SCR [9,10,11]. There aren’t many data on the effect on tumor regression due to a prolonged interval after SCR in locally advanced rectal cancer: Pach et al and Stockholm III trial don’t produce significant different with delayed surgery [12]. The aim of this study was to evaluate the TRG as indicator of response to SCR followed by a progressive prolonged interval prior to surgery in patients with middle and distal rectal adenocarcinoma

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Conclusion