Postoperative recurrence in locally advanced rectal cancer: how does neoadjuvant treatment affect recurrence pattern?

Area of Science:

• Oncology
• Surgical Oncology
• Gastrointestinal Oncology

Background:

• Locally advanced rectal cancer (LARC) treatment has evolved to include neoadjuvant chemoradiotherapy (nCRT) and/or neoadjuvant chemotherapy (NAC) alongside surgery.
• Limited data exist on disease recurrence patterns following these diverse treatment strategies.

Purpose of the Study:

• To compare disease recurrence rates and patterns after different treatment modalities for LARC.
• To identify optimal surveillance strategies based on recurrence data.

Main Methods:

• Retrospective analysis of 332 patients with clinical stage II-III rectal cancer undergoing curative surgery (July 2005-February 2021).
• Assessment of cumulative incidence and site of first recurrence.
• Median follow-up of 4.6 years.

Main Results:

• Overall recurrence rate was 23.5% with no significant difference between surgery alone (23.3%), nCRT (21.6%), and NAC (26.5%) groups.
• Local recurrence was higher than distant metastasis in the NAC group; all nCRT recurrences were distant.
• Recurrence rates were higher in nCRT and NAC groups for pathological stage 0-I disease.
• Resection of distant-only recurrences improved overall survival (HR 0.34).
• Over 80% of recurrences occurred within 2.2 years, and 98.7% within 5 years post-surgery.

Conclusions:

• Intensive surveillance for distant metastases, especially within the first 2 years, is vital regardless of neoadjuvant treatment.
• Close follow-up is necessary even after neoadjuvant treatment achieves pathological downstaging (stage 0-I).
• Curative resection of isolated distant recurrences significantly benefits overall survival.