Published in:
Open Access 01-02-2017 | Magnetic Resonance
The assessment of local response using magnetic resonance imaging at 3- and 6-month post chemoradiotherapy in patients with anal cancer
Published in: European Radiology | Issue 2/2017
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Objectives
To 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).
Methods
From 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).
Results
Seven 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.
Conclusions
Post-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.