71722 - Favourable 5-year survival in patients with isolated colorectal cancer lung metastases treated surgically with curative intent – a retrospective study

Introduction The benefit of surgical resection for colorectal cancer (CRC) lung metastases is unclear. The aim was to investigate the incidence, treatment strategy and overall survival (OS) in CRC patients with isolated lung metastases. Method CRC patients with isolated lung metastases following curative resection were retrospectively analysed using data from the Swedish Colorectal Cancer Registry and medical charts. Patients treated within Region Skåne during 2010 – 2016 were eligible. Exclusion criteria were previous or concurrent metastases at other organ sites. Patients were divided into synchronous/metachronous lung metastases and curative/palliative treatment intent. The primary endpoint was OS. Multivariable Cox-regression and Kaplan-Meier survival analysis were performed. Result Of 8457 patients, 93 (1.1%) had isolated lung metastases (53 synchronous/40 metachronous). In all, 53 patients were treated with curative intent where most (51/53, 96%) were managed surgically. Forty patients were considered palliative and received either chemotherapy or best supportive care. Five-year OS was 42% (39/93), median 49 months (IQR [22 – 60]) for the entire cohort, and 68% (36/53), median 60 months (IQR [53 – 60]) and 7.5% (3/40), median 22 months (IQR [12 – 33]) for curative and palliative patients, respectively. In multivariable analysis, younger age (hazard ratio (HR) 1.04, confidence interval (CI): 1.01 – 1.07), the number of lung metastases (HR 1.64, CI: 1.08 – 2.47) and unilateral distribution (HR 0.41, CI: 0.20 – 0.84) were associated with better survival. Discussion Isolated CRC lung metastases are rare. Patients treated with curative intent undergoing surgical resection had a favourable prognosis, especially if the lung metastases were solitary and distributed unilaterally.