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Extended total mesorectal excision in locally advanced rectal cancer (T4a) and the clinical role of MRI‐evaluated neo‐adjuvant downstaging
Author(s) -
Larsen S. G.,
Wiig J. N.,
Emblemsvaag H. L.,
Grøholt K. K.,
Hole K. H.,
Bentsen A.,
Dueland S.,
Vetrhus T.,
Giercksky K.E.
Publication year - 2009
Publication title -
colorectal disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.029
H-Index - 89
eISSN - 1463-1318
pISSN - 1462-8910
DOI - 10.1111/j.1463-1318.2008.01649.x
Subject(s) - medicine , colorectal cancer , total mesorectal excision , radiation therapy , adjuvant , magnetic resonance imaging , stage (stratigraphy) , adjuvant radiotherapy , radiology , cancer , surgery , paleontology , biology
Objective To compare the clinical ability of MRl taken before and after neo‐adjuvant treatment in locally advanced rectal cancer (LARC) to predict the necessary extension of TME (ETME) and the possibility to achieve a R0 resection. Method Prospective registration of 92 MRI evaluated T4a cancers undergoing elective surgery between 2002 and 2007 in a tertiary referral centre for multimodal treatment of rectal cancer. Results MRI identified patients in need of neo‐adjuvant treatment and predicted T‐downstaging in 10% and N‐downstaging in 59%. Seventy‐nine percent R0 resections, 18% R1 and 3% R2 were obtained after ETME in 95% of the patients and TME in the rest. Higher tumour regression grade (TRG) was achieved in higher ypT‐stage ( P < 0.01). Preoperative chemo radiotherapy resulted in that more patients obtained TRG1‐3 compared to those receiving radiotherapy (79% vs. 57%, P = 0.02). The pelvic wall was the area of failure in 70% of the R1 resections. Tumour cells outside the mesorectal fascia scattered within fibrosis was found in 18 TRG2‐3 among 33 ypT4 tumours (55%). Conclusion MRl cannot discriminate tumour within fibrosis. Therefore, if a R0 resection is the goal, we advocate optimal surgery in accordance with the pre‐treatment MRI. Post treatment MRI is a poor predictor of final histology and should not be relied upon to guide the extent of surgical resection. The study has initiated a new approach to histopathological classification of the removed specimen where we introduce a MRI assisted technique for investigating the areas at risk outside the mesorectal fascia in the specimen.