Effect of neoadjuvant concurrent three-dimensional conformal chemoradiotherapy with conventional two-dimensional chemoradiotherapy in locally advanced rectal cancer

Abstract

Background: Rectal carcinoma is a prevalent clinical condition, and treatment hinges on factors like tumor specifics, staging, grading, and histopathological characteristics. While surgery remains the primary treatment, neoadjuvant chemoradiotherapy, particularly using 3D-CRT, has proven effective in reducing local recurrence rates for locally advanced cases. Alternatively, 2D-RT is considered for neoadjuvant treatment. This study aimed to compare the impact of neoadjuvant concurrent three-dimensional conformal chemoradiotherapy with conventional two-dimensional chemoradiotherapy in the context of locally advanced rectal cancer. Methods: In this multicentre quasi-experimental study, 60 patients with biopsy-proven adenocarcinoma and clinically confirmed locally advanced rectal cancer, were divided into Group A (receiving oral capecitabine with three-dimensional conformal radiotherapy) and Group B (receiving the same capecitabine dose with 50 Gy two-dimensional radiotherapy). After surgery within 6-12 weeks, outcomes were analysed. Results: After neoadjuvant chemoradiotherapy, clinical complete response rates were 16.7% in Group A and 10.0% in Group B, with a higher pathological complete response in Group A (10.0% vs. 3.3%). Tumor downsizing occurred in 83.3% of Group A and 73.3% of Group B, and sphincter-sparing surgery was achieved in 73.3% of Group A and 56.7% of Group B. Grade 2 toxicities included anemia (10.0% vs. 13.3%), leucopenia (13.3% vs. 20.0%), diarrhoea (10.0% vs. 16.7%), proctitis (13.3% vs. 40.0%), and urinary toxicity (10.0% vs. 20.0%). Grade-1 toxicities were nausea (20.0% vs. 40.0%), vomiting (20.0% vs. 36.7%), mucositis (56.7% vs. 60.0%), hand-foot syndrome (33.3% vs. 40.0%), and urinary toxicity (43.3% vs. 56.67%), with significant proctitis in Group A (p=0.012). Other toxicities showed non-significant p-values (>0.05). Conclusions: Tumour response was not statistically significant between the patients of concurrent 3D-CRT and 2D-RT Arms. But the patients of 3D-CRT arm showed better response arithmetically. Also, there was an observable significant reduction of toxicities (lower gastrointestinal) in the 3D-CRT arm.