Supplementary Material for: Treatment of colorectal lung metastases: two centers retrospective study

Introduction
Clear guidelines for colorectal lung metastases (LM) treatment are not available. This study aimed to provide insight in the treatment strategies and efficacy of local and systemic therapy in patients with LM eligible for (potentially) curative treatment.

Material and methods
This was a retrospective study of patients with ≤5 LM discussed in two tertiary referral centers. Patient and tumor characteristics were compared between treatment groups. Treatment strategies were compared between centers and survival data between treatment groups, local treatment modalities, and treating centers.

Results
Ninety-two patients (median 2 LM) were included. Seventy-one (77%) patients underwent local treatment (17 surgery, 13 ablation, 38 radiotherapy, 3 combination of local treatments) and 21 (23%) with systemic therapy alone. The latter group more frequently had extra pulmonary metastases (81.0% vs 26.8%, p<0.001) and synchronous presentation of LM (23.8% vs 7.0%, p=0.045). Choice of local versus systemic therapy and time to start treatment after diagnosis (median 109 days, IQR 44-240 vs 88 days, IQR 53-168) were comparable between centers. Three-year survival rates did not differ between treatment groups, local treatment modalities, or treating centers.

Conclusion
Treatment strategies and oncological outcomes were rather similar between centers. Survival outcomes were not different between locally and systemically treated patients.