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

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.

Short-course versus long-course neoadjuvant chemoradiotherapy in patients with rectal cancer: preliminary results of a randomized controlled trial

“…So, the question is why short-course chemoradiation has produced such a good result. There are several reasons that could explain the more favorable results in this study; firstly, the precise delineation of target volumes based on international guidelines [14] and the strict confirmation of treatment plans, considering the sufficient coverage of PTV and also the dose of organs-at-risk; second, administration of capecitabine with radiotherapy instead of bolus 5FU is shown to be associated with fewer toxicities and higher response rates in a study by Haddad et al [30]; third, prolonging the interval between radiotherapy completion and surgery to more than 8 weeks, as this has been demonstrated by Rega et al [31] to reduce adverse events and increase response to neoadjuvant therapy. In our study, the interval from end of radiotherapy to surgery was higher compared with the majority of other similar studies.…”

Tumour regression after radiotherapy for rectal cancer – Results from the randomised Stockholm III trial

“…173 However, a higher grade of tumour regression, and even pCR, can be acheived if surgery is delayed at least 4 weeks after SRT. 149,[174][175][176] CRT induces more pCR than SRT, mainly because of the timing of surgery. 142,177 Another, registry based, study found that SRT-delay was less likely to induce pCR compared to CRT, adjusted OR (95% CI) 0.3 (0.2-0.5).…”

Gender-related prognostic significance of clinical and biological tumor features in rectal cancer patients receiving short-course preoperative radiotherapy

“…2,4 However, in some centers, apart from treatment with 5 × 5 Gy with a short (5-7 days) break, also 5 × 5 Gy and a long (4-5 weeks) break schedule before surgery is applied, and both were used in our study. Some authors 1,[5][6][7] suggest that SCRT with delayed surgery is suitable for early cancer.…”