P-298 Adjuvant chemotherapy in resected lung-limited metastatic patients with colorectal cancer

Due to the lack of data and recommendations on the curative resection of isolated lung metastases (LM) from colorectal cancer (CRC), the same treatment approach is mainly reserved for them as for metastatic liver disease, despite differences in their biological behavior. In particular, the benefit of chemotherapy after pulmonary metastasectomy remains unclear. Our study evaluated the role of systematic thoracic lymphadenectomy during lung metastasectomy in better defining postoperative prognosis, increasing staging rate, and selecting more appropriate postoperative treatment. We retrospectively collected data from 260 pts (aged 18-85) who underwent CRC lung metastasectomy with radical intent, from December 2002 to January 2022 at four Italian Centers: the Division of Thoracic Surgery at “A. Businco Cancer Center” in Cagliari, the Division of Thoracic Surgery at “Città della Salute e della Scienza” in Tourin, the Department of Thoracic Surgery at “IRCCS Azienda Ospedaliero-Universitaria” in Boulogne, and the Medical Oncology Unit of the University Hospital of Cagliari. Statistical analysis was performed with MedCalc (survival distribution: Kaplan-Meier; survival comparison: log-rank test; association between categorical variables: Fisher's exact test). Of 260 patients, 126 underwent thoracic lymphadenectomy following lung metastasectomy, and 18 resulted in nodal involvement. Interestingly, among 188 patients preoperative examined with computed tomography and 18-FDG positron-emission-tomography, the nodal pathological examination resulted in nodal upstaging in 16 clinically negative cases. Positive thoracic lymph nodes affect overall survival (OS) (p < 0.0001), and adjuvant chemotherapy in patients with lymph node involvement provides a statistically significant benefit on OS (p < 0.0001). In contrast, no other clinicopathologic features impacting OS identified patients who benefited from adjuvant therapy. Although limited by retrospective analysis of a small cohort of patients, our study suggests that thoracic lymphadenectomy during pulmonary metastasectomy from CRC may represent a tool in staging with a predictive role for prognosis and in identifying patients who could benefit from adjuvant therapy after surgery.