Micro-lymphatic invasion impact prognosis of intrahepatic cholangiocarcinoma independent of lymph node metastasis and micro-vascular invasion.

BACKGROUND

To evaluate the prognostic significance of micro-lymphatic invasion (MLI), independent of lymph node metastasis (LNM) and micro-vascular invasion (MVI) in patients with intrahepatic cholangiocarcinoma (ICC).

METHODS

We conducted a retrospective cohort study of 137 ICC patients who underwent curative resections between January 2017 and December 2022 in Huashan Hospital. Patients were categorized based on MLI and MVI status, determined by D2-40, α-SMA, CD34, CK19 immunostaining in multi-sites of tumor and para-tumor. Recurrence-free survival (RFS) and overall survival (OS) were compared between groups.

RESULTS

The median OS was 34 months, with 1-year, 2-year, and 3-year OS rates of 90.7 %, 69.4 %, and 39.5 %, respectively. Patients with LNM exhibited significantly poorer OS (median 18 months) and RFS (median 7 months) compared to those without LNM (38 vs. 18 months). Furthermore, MLI was associated with reduced OS (24 months for MLI (+) vs. >60 months for MLI (-)) and RFS (12 vs. >60 months). Among patients without LNM, those with MLI(+) exhibited significantly poorer OS and RFS compared to those without MLI, mirroring the poor prognosis of patients with potential LNM. MVI (+) showed a trend towards reduced OS (24 vs. 36 months), and significantly impacted RFS (12 vs. 18 months). Additionally, multivariate analysis identified carcinoembryonic antigen, carbohydrate antigen 19-9, perineural invasion and MLI as independent prognostic factors for OS. For RFS, carbohydrate antigen 19-9, tumor size, perineural invasion and MLI were found to be independent prognostic factors.

CONCLUSIONS

The results of the study highlight the critical importance of incorporating MLI into prognostic evaluations.