Changing landscape of multidisciplinary management in locally advanced rectal cancer (2015-2023).

57 Background: Multidisciplinary management of locally advanced rectal cancer has evolved over the last decade with publication of multiple prospective clinical trials. This study identifies trends in the changes to treatment of rectal cancer over time. Methods: Data from a single-center cohort of patients with cT3-4 or N+ tumors located 1-15 cm from the anal verge were analyzed from January 1, 2015, to December 31, 2023. Results: A total of 1,176 patients were identified. Fifty-five (5%) proceeded directly to surgery and 1,121 (95%) received neoadjuvant therapy, including total neoadjuvant therapy (TNT) with chemoradiotherapy and systemic chemotherapy (924; 82%), chemotherapy alone (118; 11%), chemoradiotherapy alone (38; 3%), or immunotherapy/targeted therapy (41; 4%). Following neoadjuvant therapy, most patients entered organ preservation protocols: 793 (71%) underwent active surveillance, 328 patients (29%) underwent immediate surgery. Trends over time include increasing use of (i) TNT with chemoradiation and consolidation chemotherapy (from 10% in 2015 to 81% in 2023), (ii) chemotherapy without radiation followed by surgery (from 13% to 21%), (iii) immunotherapy/targeted therapy (from 0% to 10%), and (iv) capecitabine (rather than IV 5-fluorouracil) in combination with oxaliplatin (from 4% to 56%). In the TNT group, nonoperative management with sustained clinical complete response rose from 38% to 50%, and the combined rate of clinical or pathological complete response increased from 49% to 55%. With increasing identification of clinical complete responders who can avoid surgery, the rate of pathological complete response decreased from 18% to 6%. Robot-assisted surgery was preferred (530; 88%), and avoidance of ileostomy was more common in patients receiving chemotherapy (49; 47%) than for those receiving TNT followed by surgery (12; 4%). Complications of Clavien-Dindo grade 3 or higher and anastomotic leaks remained stable at 10% and 1.8%, respectively. Conclusions: Recent trends in multidisciplinary management of locally advanced rectal cancer show that results of prospective trials have been quickly incorporated into clinical care. Patients with locally advanced rectal cancer have many treatment options allowing for more patient-centric decision making.