Individualized T3-4N+ Rectal Cancer Treatment Strategies: Exploring the Efficacy of Preoperative Synchronized Lateral Lymph Node Simultaneous Integrated Boost Radiation Therapy.

OBJECTIVE

This study aims to assess the impact of preoperative synchronized lateral lymph node simultaneous integrated boost radiation therapy on the prognosis of T3-4N+ rectal cancer patients.

METHODS

A retrospective analysis was performed on 35 patients with rectal cancer from Beijing Luhe Hospital affiliated to Capital Medical University from August 1, 2019 to April 30, 2023, including 22 patients with T3-4N+ rectal cancer, all of whom received the above preoperative therapy: planning gross tumor volume (PGTV): 95% PGTV 55 Gy/2.2 Gy/25 times; planning gross tumor volume of node (PGTVnd): 95% PGTVnd 60 Gy/2.4 Gy/25 times; and planning target volume (PTV): 95% PTV 50 Gy/2 Gy/25 times. Total mesorectal excision (TME) was performed 8-12 weeks after the radiotherapy. The primary endpoints were postoperative pathologic complete response (pCR) rate, downstaging rate, and 1-, 2-, and 3-year local regional recurrence-free survival (LRRFS). The secondary endpoints were anal retention rate, 1-, 2-, and 3-year event-free survival (EFS), overall survival (OS) rates, treatment-emergent adverse events (TEAEs), and perioperative complications.

RESULTS

All 22 patients completed treatment, with pCR rate of 22.7% (5/22), anal preservation rate of 77.3% (17/22), tumor downstaging (T-downstaging) rate of 95.5% (21/22), and nodal downstaging (N-downstaging) rate of 100% (22/22), and 1-year postoperative LRRFS, EFS, and OS rates of 100%, 80%, and 86%, respectively; 2-year LRRFS, EFS, and OS rates of 90%, 63%, and 75%, respectively; and 3-year LRRFS, EFS, and OS rates of 90%, 63%, and 63%, respectively. Only two cases of Grade 3 adverse events occurred, which were clinically manageable and did not require permanent treatment cessation.

CONCLUSION

This retrospective analysis demonstrated encouraging short-term outcomes, including a 22.7% pCR rate and a 3-year LRRFS of 90%, with manageable toxicity. Nonetheless, these findings should be interpreted with caution due to the limited sample size and absence of a control arm.