186P Neoadjuvant radiotherapy of locally advanced rectal cancer: short-course radiation VS long-course chemo radiation

Abstract

Aim/Background: To compare toxicity profile, patient compliance, surgical resectability & pathological response in short course radiation vs long course chemoradiation in locally advanced rectal cancer. Methods: All patients underwent staging workup as per NCCN guidelines. 87 patients with stage II to III rectal cancer were treated with short course(SC) radiation(RT) (25Gy/5Fr followed by surgery within 10 days, n= 36) or long course(LC) chemoRT (50.4Gy/28Fr with chemotherapy with 5FU 375mg/m2 and calcium leucoverin 20mg/m2 in 1st & last week of RT followed by surgery after 6–8 weeks, n = 51). Acute toxicities were assessed using revised RTOG criteria. The resectability potential were accessed by R0, R1 and R2 resections. Histopathological reporting was done by a single pathologist. The patients were characterised into three–(1) complete pathological response (2) down staging response (3) stable or progressive disease (both 1 & 2 are considered as down staging ‘ + ’ and 3 as down staging ‘-’). Patient compliance assessed based on the extend of completion of planned treatment. Results: 80 out of the 87recruited patients received neoadjuvant treatment & 59 completed the planned treatment. About half of the patients in LC CRT arm developed skin & GI toxicities (p <.001). 2 patients developed haematological toxicities.In the SCRT arm none developed skin, GI or haematological toxicities. R0 resection was 100% & 78.3% in LC CRT & SCRT arms respectively (p = 0.007). The pathological response for T(p = 0.004) & N(p = 0.026) status were 83.3% & 94.4% and 47.8% & 69.6% for LC CRT & SCRT arms respectively. Regarding the treatment compliance 70.6% in the LC CRT arm & 63.9% in the SCRT arm completed the planned treatment (p = 0.510). Conclusions: The incidence of GI and skin toxicities were significantly high in LC CRT arm but they were managable with no treatment related deaths. With regard to downstaging & pathological complete response LC CRT is significantly better than SCRT. Our results are similar to various other international trials. To conclude, the results are favouring long course chemo radiotherapy ahead of short course radiotherapy in managing locally advanced carcinoma rectum with acceptable treatment related toxicities. Clinical trial identification: CTRI/2013/09/004035 Disclosure: All authors have declared no conflicts of interest.