MRI tumor volume reduction rate vs tumor regression grade in the pre-operative re-staging of locally advanced rectal cancer after chemo-radiotherapy

作者：Neri Emanuele^*; Guidi Elisa; Pancrazi Francesca; Castagna Maura; Castelluccio Elisa; Balestri Riccardo; Buccianti Piero; Masi Luca; Falcone Alfredo; Manfredi Bruno; Faggioni Lorenzo; Bartolozzi Carlo

来源：European Journal of Radiology, 2015, 84(12): 2438-2443.

DOI：10.1016/j.ejrad.2015.08.008

• Rectal cancer
• MR
• Staging
• Image processing
• Quantitative imaging

Objective: To compare tumor volume reduction rate (TVRR) measured by MR volumetry after preoperative chemoradiotherapy(CRT) and pathological tumor regression grade (TRG) in locally advanced rectal cancer (LARC).
Material and methods: In total, 20 patients with LARC (cT3-T4) treated with CRT followed by Total Mesorectal Excision (TME) between April 2011 and April 2013 were analyzed retrospectively. Pre- and post- CRT tumor volumes (MR volumetry) were measured on 3D MR sequences. TVRR was determined using the equation TVRR (%) = (pre-CRT tumor volume post-CRT tumor volume) x 100/pre-CRT tumor volume. The downstaging (defined as ypTO-T2) of tumor mass was evaluated and the correlation between TVRR and TRG was calculated with the method proposed by Dworak using the Spearman rank test.
Results: The median TVRR was 77.3% (range, 26.4-99.3%); TVRR was >60% in 18 cases (90%) and in 8 of these patients (44.4%) it was >80%. Downstaging of tumor lesions was obtained in 15 patients (75%). In 4 cases there was a complete tumor regression (TRG4) at histological examination and in the same patients there was also a TVRR >80% measured by MR volumetry. A statistically significant correlation between TVRR and TRG = 0.5466, p = 0.0126) was observed.
Conclusion: TVRR after preoperative CRT correlates with TRG in LARC. The MR volumetry is a prognostic factor to estimate the tumor response after preoperative CRT. TVRR data may be an useful biomarker for tailoring surgery and postoperative adjuvant chemotherapy.

• 出版日期2015-12