The assessment of local response using magnetic resonance imaging at 3- and 6-month post chemoradiotherapy in patients with anal cancer

Abstract

ObjectivesTo assess the use of MRI-determined tumour regression grading (TRG) in local response assessment and detection of salvageable early local relapse after chemoradiotherapy (CRT) in patients with anal squamous cell carcinoma (ASCC).MethodsFrom a prospective database of patients with ASCC managed through a centralised multidisciplinary team, 74 patients who completed routine post-CRT 3- and 6-month MRIs (2009–2012) were reviewed. Two radiologists blinded to the outcomes consensus read and retrospectively assigned TRG scores [1 (complete response) to 5 (no response)] and related these to early local relapse (within 12 months) and disease-free survival (DFS).ResultsSeven patients had early local relapse. TRG 1/2 scores at 3 and 6 months had a 100 % negative predictive value; TRG 4/5 scores at 6 months had a 100 % positive predictive value. All seven patients underwent salvage R0 resections. We identified a novel ‘tram-track’ sign on MRI in over half of patients, with an NPV for early local relapse of 83 % at 6 months. No imaging characteristic or TRG score independently prognosticated for late relapse or 3-year DFS.ConclusionsPost-CRT 3- and 6-month MRI-determined TRG scores predicted salvageable R0 early local relapses in patients with ASCC, challenging current clinical guidelines.Key Points• Post-chemoradiotherapy MRI (3 and 6 months) helps local response assessment in ASCC.• The MRI-TRG system can be used reproducibly in patients with ASCC.• The TRG system facilitates patient selection for examination under anaesthesia and biopsy.• The use of MRI-TRG predicts for detection of salvageable early local relapses.• The TRG system allows for a standardised follow-up pathway.Electronic supplementary materialThe online version of this article (doi:10.1007/s00330-016-4337-z) contains supplementary material, which is available to authorized users.

Association of Coloproctology of Great Britain & Ireland (ACPGBI): Guidelines for the Management of Cancer of the Colon, Rectum and Anus (2017) – Anal Cancer

“…Very early (6–8 week) assessment by MRI or other imaging modalities is generally unhelpful and is not recommended (Goh et al ., ). However, recent data indicates that MRI assessment at 3 and 6 months may be able to identify those at risk of early relapse, who are amenable to R0 salvage (Kochhar et al ., ).…”

“…Following CRT, MRI pelvis is able to demonstrate tumour regression and document sustained response. The benefit of routine use of MRI in addition to clinical assessment alone remains unclear with no general consensus (Goh et al ., ; Gourtsoyianni & Goh, ; Kochhar et al ., ; Kochhar et al ., ). NCCN and ESMO guidelines are also discordant on this issue, with MRI pelvis indicated as an option within the ESMO but not the NCCN guidelines (Glynne‐Jones et al ., ; National Comprehensive Cancer Network, ).…”

Radiomics and Machine Learning in Anal Squamous Cell Carcinoma: A New Step for Personalized Medicine?

“…Disregarding radiomics, MRI analysis struggles to provide valuable prognostic help [28]. Nonetheless, it is worth noting that the use of MRI-determined tumor regression grading (TRG) to predict local relapse at three and six months post-CRT has been associated with an almost 100% negative predictive value for TRG 1/2 scores at three and six months, and almost 100% positive predictive value for TRG 4/5 at six months [29]. Abbreviations: CRT, chemo-radiotherapy; MRI, magnetic resonance imaging; RCS, radiomics; GLCM, grey-level co-occurrence matrix; DFS, disease-free progression; RF, random forest; DWI, diffusion weighted imaging; DCE, dynamic contrast enhanced; ADC, apparent diffusion coefficient; ROC AUC, area under the curve of the receiver-operating characteristic curve; PET-CT, positron emission tomography and computed tomography; SUV, standardized uptake value; MTV, metabolic tumor volume; TLG, total lesion glycolysis; ZMP, Z-normalized MTV and SUV peaks; HPV, human papilloma virus; PFS, progression-free survival; NGLDM, neighborhood grey-level different matrix.…”

Three-Dimensional (3D) Magnetic Resonance Volume Assessment and Loco-regional Failure in Anal Cancer: Early Evaluation Case-Control Study

“…Tumour regression grading has been found to predict for early local failure in SCCA. (40) Further work examining the role of measured tumour volume reduction following CRT may provide more prognostic information; however, differentiating tumour from brosis and oedema following CRT is a signi cant challenge.…”