Clinical impact and network of determinants of tumour necrosis in colorectal cancer.

BACKGROUND: The disease outcome in colorectal cancer (CRC) can vary in a wide range within the same tumour stage. The aim of this study was to clarify the prognostic value and the determinants of tumour necrosis in CRC. METHODS: The areal proportion (%) of tumour tissue showing coagulative necrosis was evaluated in a cohort of 147 CRC patients and correlated with basic clinicopathological characteristics, microvascular density (MVD), cell proliferation rate, KRAS and BRAF mutations, and survival. To validate the prognostic significance of tumour necrosis, an independent cohort of 418 CRC patients was analysed. RESULTS: Tumour necrosis positively correlated with tumour stage (P=8.5E-4)-especially with T class (4.0E-6)-and inversely correlated with serrated histology (P=0.014), but did not significantly associate with cell proliferation rate, MVD, and KRAS or BRAF mutation. Abundant (10% or more) tumour necrosis associated with worse disease-free survival independent of stage and other biological or clinicopathological characteristics in both cohorts, and the adverse effect was directly related to its extent. High CD105 MVD was also a stage independent marker for worse disease-free survival. CONCLUSIONS: Tumour necrosis percentage is a relevant histomorphological prognostic indicator in CRC. More studies are needed to disclose the mechanisms of tumour necrosis.