Complete blood counts as potential risk factors of early dissemination to liver and lungs in resected colorectal cancer: a retrospective cohort study.

PURPOSE: Liver and lung metastases demonstrate distinct biological, particularly immunological, characteristics. We investigated whether preoperative complete blood count (CBC) parameters, which may reflect the immune system condition, predict early dissemination to the liver and lungs in colorectal cancer (CRC).

METHODS

In this retrospective single-centre study, we included 268 resected CRC cases with complete 2-year follow-up and analysed preoperative CBC for association with early liver or lung metastasis development. Next, selected CBC and clinicopathological parameters were analysed with uni- and multivariable Cox regression. Independent factors affecting liver or lung metastasis-free survival were incorporated into composite scores, which were further evaluated with receiver operating characteristic (ROC) curves and dichotomised using a modified, specificity-focused, Youden approach to identify particularly high-risk patients.

RESULTS

Compared to metastasis-free patients, early liver metastases were related to decreases in red blood cells, haematocrit, lymphocytes and elevated monocyte-to-lymphocyte ratio, while lung metastases to lower eosinophil counts. A composite score of independent factors (erythrocytopenia, lower lymphocyte count and pN) yielded HR of 8.01 (95% CI 3.45-18.57, p < 0.001) for liver-specific metastasis-free survival (MFS). For lung-specific MFS, the combination of eosinopenia, pN and primary tumour location showed HR of 13.69 (95% CI 4.34-43.20, p < 0.001).

CONCLUSION

Early CRC metastases to the liver and lungs are associated with partially divergent clinicopathological and peripheral blood features. We propose simple, clinically implementable scores, based on routinely assessed parameters, to identify patients with an increased risk of early dissemination to the liver or lungs. After validation in independent cohorts, these scores may provide easily available prognostic information.