Accuracy of high-resolution rectal magnetic resonance imaging re-staging with histopathology in locally advanced rectal cancer after neoadjuvant chemoradiotherapy

Autor: Supparerk Laohawiriyakamol, Supong Worathanmanon, Teeravut Tubtawee, Kanet Kanjanapradit, Surasak Sangkhathat, Nannapat Pruphetkaew, Virasakdi Chongsuvivatwong
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Asian Journal of Surgery, Vol 44, Iss 1, Pp 275-279 (2021)
Druh dokumentu: article
ISSN: 1015-9584
DOI: 10.1016/j.asjsur.2020.07.001
Popis: Background/objective: Re-staging of locally advanced rectal cancer (LARC) following neoadjuvant chemoradiotherapy (NCRT) is a crucial step in surgical decision-making. Currently, MRI is the imaging of choice for evaluation of LARCs, however, the diagnostic accuracy of this modality is inconsistent. In this study, we evaluated the diagnostic accuracy of MRI in LARC and analyzed the factors that influenced the accuracy. Methods: The records of 133 patients diagnosed with LARC who were operated on during 2011–2018 were retrospectively reviewed. All patients received NCRT followed by re-staging based on high-resolution rectal MRI. The MRI results were analyzed for their yT and yN accuracy and anal sphincter involvement and compared with the related histopathological studies after definitive surgery. Results: Re-staging MRIs gave overall accuracy in both the yT stage and yN evaluation of 85% (K 0.45 and 0.21, respectively). The MRI tended to overstaging for tumor invasion and understaging for lymph node involvement (sign test p-values = 0.017 and 0.022, respectively.) The highest accuracy of the yT stage was yT4b (93%, K 0.71). The study found that larger tumors (>3 cm) were associated with significantly higher accuracy in the yT readings while lack of lymphovascular invasion was associated with higher accuracy in the yN readings. The negative predictive value for anal sphincter involvement was 100%. Conclusion: MRI has limited accuracy in post-NCRT re-staging in LARC, tending to give overstaged yT readings and understaged yN readings. An MRI exclusion of sphincteric involvement is highly reliable.
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