Abstract 273P
Background
Pathological complete response (pCR) after preoperative chemoradiotherapy (CRT) is vital in assessing rectal cancer treatment efficacy. Neoadjuvant therapy is standard for locally advanced cases, possibly eradicating tumors and lowering local recurrence risk. pCR rates inform decisions on watch-and-wait strategies, suggesting surgery delay to reduce complications. This study seeks to determine the proportion of rectal cancer patients achieving pCR post-neoadjuvant therapy.
Methods
We retrospectively assessed outcomes of neoadjuvant radiotherapy (+/-chemotherapy) in 464 locally advanced rectal cancer patients treated from January 1993 to June 2023. Data analysis focused on pathological complete response and survival outcomes.
Results
Among our patient cohort,464 patients were diagnosed with locally advanced stage rectal cancer, with MRI utilized in 72% of cases for initial staging.The majority (n = 400, 84%) had tumors located in the mid or low rectum. Patients predominantly received long-course radiotherapy (99%) (with a median dose of 50.4 Gy over 28 fractions) with or without chemotherapy. The median age was 60 years (range, 18-90 years), with 23.7% (110 patients) aged 70 and above. Out of 464 patients, 16 did not undergo surgery, while 448 patients underwent surgery, with 130 undergoing abdominoperineal resection (APR) and 325 undergoing low anterior resection (LAR). Among the surgically treated patients, 7(15.8%) achieved a pathological complete response. The median time from radiotherapy to surgery was 15 weeks, with a median follow-up of 60 months (range, 6-275 months). Local recurrence occurred in 9.5% of patients, while 28.7% developed distant metastases. None of the patients who achieved a pathological complete response developed local recurrence.
Conclusions
Irrespective of the treatment regimen, neoadjuvant radiotherapy appears to be an effective and safe treatment for patients with rectal adenocarcinoma. The pathological complete response rate in our center was similar to that reported in the literature. Rigorous patient selection and close follow-up should be implemented if the ''watch-and-wait'' strategy is adopted in our population.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.