Relevance of indeterminate pulmonary nodules in predicting distant metastasis in colorectal cancer.

BACKGROUND

The detection of indeterminate pulmonary nodules (IPN) at diagnosis of colorectal cancer (CRC) has increased. However, there is limited information on predictive factors for its progression (pPF) to pulmonary metastases (PM). This study aims to identify these pPF to select appropriate management strategies.

METHODS

Single-center observational retrospective study including patients who underwent elective surgery for first non-metastatic CRC episode (January 2016- June 2019) with IPN at diagnosis. Patients were divided into those who developed PM in the same location as previous IPN (LM group) and those who did not (FM group).

RESULTS

One hundred twenty-one patients were included; 4.9% developed PM in the same location as previous IPN. Univariate analysis revealed a significant difference in IPN size between groups with 8 (5, 10) mm in LM versus 3 (1, 5) mm in FM (P=0.006). ROC curve showed a size of ≥5 mm as the best cutoff point to predict IPN progression. Multivariate analysis identified size ≥5mm as the only independent pPF (OR 11.9, 95%CI 1.3-105.8, P=0.026). The median time to diagnose PM in LM group was 13.8(SD 5.2) months.

CONCLUSIONS

We recommend a closer follow-up for patients with CRC and IPN ≥5 mm at diagnosis so they will have a higher risk of developing PM.