Neuroendocrine carcinoma (NEC) of colorectal origin are in minority of NEN. The aim of this retrospective study was to determine the natural history of NEC and outcomes in terms of OS (overall survival) and PFS (progression free survival), also to assess clinical, pathologic and prognostic factors of this group of cancers.
All patients with NEC or mix adenoca and NEC (MANEC), confirmed in histology WHO classification 2010, were include of the study. Local ethics committee accept this retrospective review. All patient data sets were review and analysed including OS and PFS for clinical and pathological factors.
A total of 67 pts were include in this study, 33% of all NEN in this localisation. A female to male ratio was 1,48. There were 15 MANEC (22%) and 52 NECG3 (52%). At initial diagnosis local disease was noted in 11 subjects (16%), regional lymph nodes spread in 25 subjects (37%) and distant mts noted in 31 pts (46%). Whole large bowel was also divide on anatomical regions of primary localisation, including: caecum area 19 subjects (28%), ascending, transverse and descending colon 16 subjects (24%), sigmoid 17 (25%) and rectal area 15 (22%). Median OS in whole group of pts was 18.0 M, in those with local spread of disease (CS I-IIIA) OS was 77.0 M, in those with regional lymph nodes involvement (CS IIIB) 26.0 M, and in those with presence of distant mts, OS was 11.0 M. Female median OS was 14.9 M compare to male 18.1 M. The localisation of primary tumour provides differences in OS as follows: caecum median OS 36 M, sigmoid 11.0 M, rectal 25.0M and rest of the colon 13.0M. The median OS in patients with NEC was 16.0 M and those with MANEC was 26.0M. Factors associated with improved OS on multivariate analysis were absence of metastatic disease both regional and distal and MANEC type, compare to pure NECG3.
Colorectal NEC are relatively common, compare to other localisation of NEC of GEP-NEN origin. Most of them are very aggressive cancers with poor prognosis. Patients appear to have a relatively better outcome if they present no regional and distant spread of disease. Also relatively better prognosis in terms of OS in those with rectal and caecal compare to other segments of large bowel NEN. The MANEC variant of colorectal NEC seems to be less aggressive behaviour compare to pure NEC.
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All authors have declared no conflicts of interest.