Is it possible to predict the side of hepatic metastases according to the primary location of colorectal cancer?

Streamline Flow of the Portal Vein Affects the Distribution of Colorectal Cancer Metastases: Clinical Reality or Just a Belief? A Systematic Review and Meta-Analysis

Background: The "streamline flow" of the portal vein (PV) is a controversial yet well-known theory presented almost 125 years ago. It states that blood from the superior mesenteric vein (SMV) goes preferentially to the right liver lobe, while splenic and inferior mesenteric veins divert blood predominantly to the left lobe, affecting this way the metastatic distribution of colorectal cancer (CRC). The aim of this systematic review is to assess its validity by examining and combining all the relevant literature with a critical eye. Materials and methods: This study constitutes a systematic review of the literature and adheres to all PRISMA system criteria. Three search engines (PubMed, Google Scholar, and the Cochrane Library) were used, and 11 out of 435 studies between 1984 and 2024 were finally included in this meta-analysis. All statistical analysis was conducted using RevMan Web, Version: 7.12.0, and Jamovi v 2.3.260 software. Results: The meta-analysis revealed that regardless of the primary location of the tumor, the metastases preferentially migrate to the right lobe due to various possible reasons. The prevalence of metastases from right colon cancer to the right liver lobe was 75%, while the prevalence of left colon cancer metastases to the right lobe was 68%. This difference was not found statistically significant. Conclusions: The theory has been proven inaccurate, at least from the perspective of the origin-associated distribution of CRC metastases in the liver lobes, and therefore bears no clear predictive value. Further research under different perspectives is essential for determining more definite conclusions.

Does portal vein anatomy influence intrahepatic distribution of metastases from colorectal cancer?

BACKGROUND

Other than location of the primary colorectal cancer (CRC), a few factors are known to influence the intrahepatic distribution of colorectal cancer liver metastases (CRLM). We aimed to assess whether the anatomy of the portal vein (PV) could influence the intrahepatic distribution of CRLM.

PATIENTS AND METHODS

Patients with CRLM diagnosed between January 2018 and December 2022 at two tertiary centers were included and imaging was reviewed by two radiologists independently. Intra-operator concordance was assessed according to the intraclass correlation coefficient (ICC). The influence of the diameter, angulation of the PV branches and their variations on the number and distribution of CRLM were compared using Mann-Whitney, Kruskal-Wallis, Pearson's Chi-square and Spearman's correlation tests.

RESULTS

Two hundred patients were included. ICC was high (> 0.90, P < 0.001). Intrahepatic CRLM distribution was right-liver, left-liver unilateral and bilateral in 66 (33%), 24 (12%) and 110 patients (55%), respectively. Median number of CRLM was 3 (1-7). Type 1, 2 and 3 portal vein variations were observed in 156 (78%), 19 (9.5%) and 25 (12%) patients, respectively. CRLM unilateral or bilateral distribution was not influenced by PV anatomical variations (P = 0.13), diameter of the right (P = 0.90) or left (P = 0.50) PV branches, angulation of the right (P = 0.20) or left (P = 0.80) PV branches and was independent from primary tumor localisation (P = 0.60). No correlations were found between CRLM number and diameter (R: 0.093, P = 0.10) or angulation of the PV branches (R: 0.012, P = 0.83).

CONCLUSIONS

PV anatomy does not seem to influence the distribution and number of CRLM.

The tendency of segmental distribution of hepatic metastasis according to couinaud classification: a comparison of portal versus systemic route of metastatis due to primary colorectal and breast tumors

Objective

The liver is the commonest site of metastatic disease for patients with colorectal cancer (CRC), with at least 25% of patients developing liver metastasis (LM) during their illness. About 50% of patients diagnosed with metastatic breast cancer develop LM, and 5-12% of these patients develop LM as the main site of breast cancer recurrence. This study aims to determine the frequency of segmental distribution of LM seeding from portal versus systemic routes of dissemination due to primary CRC and breast carcinoma, respectively.

Material and methods

This retrospective study was conducted in a tertiary care teaching hospital in Pakistan. Ethical approval was taken from the institutional review board. A total of 587 patients were included in the study with 297 CRC patients with LM and 300 breast carcinoma patients with LM. Segment I involvement was excluded from the calculation because of the dual blood supply. Patients' detailed demographics and other information were collected on a predesigned proforma. The authors evaluated axial and multiplanar reformatted computed tomography images for LM and CRC metastasis. Data analysis was done using SPSS version 25. P value less than or equal to 0.05 was considered statistically significant.

Results

A study population of 587 patients was employed that comprised 287 CRC and 300 breast carcinoma patients. There were 179 (30.5%) male and 408 (69.5%) female patients. The mean age of patients was 54.9±13.3. The study revealed that 204 (34.8%) CRC patients showed right lobe (V, VI, VII, VIII) and 83 (14.1%) CRC patients showed left lobe involvement of metastasis while 192 (32.7%) breast carcinoma patients showed right lobe involvement and 108 (18.4%) breast carcinoma patients showed left lobe involvement in metastasis (P=0.02). We also found 40 (6.8%) colorectal and 55 (9.4%) breast carcinoma patients showed left lateral segment (II, III) involvement. Medial segment involvement (IV) was seen in 43 (7.3%) CRC patients and 53 (9%) breast carcinoma patients (P=0.03).

Conclusion

The right hepatic lobe is the predominant site of metastasis independent of the portal or systemic route of dissemination in primary carcinoma. Moreover, in left lobe metastasis medial segment (IV) is more affected in CRC while the lateral segment (II, III) is more affected in breast carcinoma.