Online

ESTRO 2020

Session Item

Clinical track: Lower GI (colon, rectum, anus)
9306
Poster
Clinical
23:00 - 23:00
SCRT and chemotherapy vs LCRT for unresectable rectal cancers. A propensity matched-pair analysis
PO-1108

Abstract

SCRT and chemotherapy vs LCRT for unresectable rectal cancers. A propensity matched-pair analysis
Authors: Engineer|, Reena(1)*[reena_engineer@rediffmail.com];Saklani|, Avanish(2);D'souza|, Ashwin(2);Mokal|, Smruti(3);Dhyani|, Aruj(1);Chopra|, Supriya(1);
(1)Tata Memorial Hospital, Radiation Oncology, Mumbai, India;(2)Tata Memorial Hospital, Surgical Oncology, Mumbai, India;(3)Tata Memorial Hospital, Statistics, Mumbai, India;
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Purpose or Objective

There is emerging evidence that Neoadjuvant short course Radiotherapy (SCRT) followed by few additional cycles of chemotherapy is equivalent to neoadjuvant long course radiotherapy (LCRT) in patients with locally advanced rectal cancer. We aimed at comparing clinical outcomes of both these approaches in this study.

Material and Methods

From the prospective database (June 2011 to April 2018), a propensity score was used to match 65 patients with rectal cancer receiving SCRT to 65 patients

receiving LCRT. Patients SCRT of 5x5 Gy was followed with 2-3 cycles of capecitabine or Capecitabine + Oxaliplatin chemotherapy. LCRT was 50Gy over 25 fractions with concurrent Capecitabine 825 mg/mt2 b.i.d. Propensity score matching was used to match the data on baseline covariates location of tumor, Differentiation on histology, CRM status on MRI using 1:1 nearest matching and 0.2 caliper.

Results

Patient and clinical tumor characteristics were similar between groups. CRM was  involved in 74% of patients. Majority tumors were large and fixed clinically and were deemed unresectable.

R0 resection rate was similar in both the groups. LCRT vs SCRT (73.8% vs 77%; P = 0.52). Pathological complete response was also similar (25% vs 17% p=0.35)

The loco regional failures were seen in 20% with LCRT vs 24% in SCRT groups.

The median follow up of 44 months for LCRT vs SCRT, the 3 year DFS was (45.4 %vs.42.4, p_0.27) and OAS (60.6% vs. 67.2%, p_0.94) was similar in both the groups.

Conclusion

In this analysis, LCRT was equivalent to SCRT in terms of tumor response to neoadjuvant therapy, disease free, and overall survival. These findings

provide evidence that SCRT followed by chemotherapy has similar oncological outcomes compared to LCRT in locally advanced initially unresectable rectal cancers.