Macrovascular tumor infiltration and circulating tumor cell cluster dynamics in patients with cancer approaching the end of life.

End-of-life events related to carcinoma lethality are poorly characterized. Herein we conducted an observational, prospective, case-control study enrolling 21 patients with solid tumors and 10 patients without known malignancy, complemented by a retrospective validation cohort of 1,250 patients with cancer. In our prospective cohort, we observed spikes in circulating tumor cell (CTC) counts, particularly clusters, immediately before death (P < 0.0001), as well as pathological evidence of macrovascular infiltration and large-vessel occlusion obtained through rapid autopsy. In the validation cohort, radiological evidence of macrovascular infiltration emerged as the strongest predictor of poor survival-independent of metastasis-in treatment-homogeneous patients with colorectal, lung, ovarian, hepatocellular or pancreatic cancer (hazard ratios = 4.0-22.4). Collectively, these findings suggest that macrovascular infiltration and spikes in CTC clusters with consequent vascular failure could be pivotal end-of-life events associated with cancer lethality, providing a rationale for future trials aimed at curbing infiltration into large vessels.