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.