Haematogenous metastastic patterns in colonic carcinoma: An analysis of 1541 necropsies

TLDR

The study aims to highlight that bone‑marrow metastases from colonic carcinoma may influence diagnosis and treatment decisions. The authors analyzed 1,541 necropsy reports from 16 centers to map the sequence of haematogenous metastasis from colorectal cancer. Results support a stepwise cascade of metastasis—first liver, then lungs, then other organs—while deviations are largely due to false negatives; only a minority of cases show non‑haematogenous spread, and incidence in other sites correlates with blood flow per gram except for the thyroid (low) and bone marrow (high), suggesting the thyroid is an unfavorable site and bone marrow a favorable one for metastatic growth.

Abstract

Abstract The sequence of events in haematogenous metastasis from colonic carcinoma was analysed, using 1541 necropsy reports from 16 centres. The findings are consistent with the cascade hypothesis that metastases develop in discrete steps, first in the liver, next in the lungs and finally, in other sites. Deviations of necropsy findings from the cascade model are largely explained on the basis of false negative reports. In only 216 of 1194 cases was there suggestive evidence that metastatic patterns (excluding lymph nodes) were causally related to lymphatic or non‐haematogenous pathways. The incidence of metastatic involvement in ‘other’ (quaternary) sites correlated with target organ blood‐flow (ml min‐) per g, only when bone marrow and thyroid were excluded. In the thyroid the incidence was lower than expected on the basis of blood flow per g tissue; this may indicate that the thyroid is an unfavourable site for metastatic growth of colonic carcinoma. In the bone marrow it is higher; the latter may be due to delivery of cancer cells via both arterial blood and the vertebral venous plexus. Recognition of this pattern of metastases in the bone marrow could be important with respect of diagnosis and therapy, in patients with colonic carcinoma.