Outcomes and prognostic factors of patients (pts) with metastatic colorectal cancer (mCRC) who underwent pulmonary metastasectomy (PM) with curative intent.

Abstract

4034 Background: Indications for PM in pts with mCRC are often based on the presence of favorable prognostic factors. We aimed to analyze the prognostic factors and outcomes of pts treated with PM for mCRC. Methods: We retrospectively identified pts with mCRC who underwent PM with curative intent between Jan 1985 and Dec 2019 at Hospital de Clínicas de Porto Alegre. Demographics, clinicopathological features and previously described prognostic factors were collected. Univariate Cox regression was performed and followed by Kaplan-Meier (KM) curves with log-rank test when significant. Results: Fifty-eight pts underwent PM. Demographics are described in Table. Wedge resection was performed in 87.9% and margins were negative in 89.1%. Mean number of lesions was 2.4 ± 1.7, with the largest measuring 1.7 ± 0.9 cm. Two or more resections were performed in 36.2%, nodal sampling in 27.3%, and nodal disease was found in 5.2%.Thirty-day readmission rate was 5.2%. One pt had a Clavien-Dindo grade IIIb complication. RAS/RAF/MMR and CK20/CDX2 were available for 13.8% and 58.6% of the sample. Median PFS 14 months (m) (95% CI 10.4 - 17.5), median OS 58 m (95% CI 33.5 - 82.4) and 5-year survival 49.8%. Unfavorable prognostic factors for OS included disease-free interval (DFI) < 24 m (40 m, 95% CI 31.8 - 48.1 vs 85 m, 95% CI 75.7 -96.2; P < 0.005), synchronous presentation (33 m, 95% CI 23.9 - 42.0 vs 77 m, 95% CI 50.7 - 103.2; P < 0.001), largest lesion size ≥ 2cm (37 m, 95% CI 22.9 - 51.0 m vs 81 m, 95% CI - 33.7 - 128.2, P = 0.019) and lack of CK20 expression (19 m, 95% CI 12.1 - 27.2 vs. 83 m, 95% CI 46.9 - 119.0; P < 0.001). More than one lesion at presentation was prognostic for PFS (11 m, 95% CI 7.6 - 14.3 vs 23 m, 95% CI 0.1 - 59.2; P = 0.003) but not OS (P = 0.11). Grade was significant at Cox regression but showed no effect in further analysis. Neither CEA at baseline or relapse, resection margins, Charlson comorbidity index (CCI) or adjuvant chemotherapy were prognostic. Conclusions: Our results suggest a benefit for select pts and PM. Lack of CK20 expression may be associated with more aggressive disease and shorter OS. Additional molecular prognostic factors after PM should be further explored. [Table: see text]