A single centre experience of in-field recurrence following pre-operative radio(chemo)therapy in patients with rectal cancer
Authors: O. Coen, L. Karsera, N. Tambe, R. Roy
Journal: Annals of Oncology (2018)

Introduction: Preoperative radio(chemo)therapy is commonly used in the management of rectal cancer. It has consistently shown to improve local recurrence rates over surgery alone and improve progression free survival1,2. There is however limited data as to what proportion of patients develop recurrence within the radiotherapy field. This retrospective review reports outcomes for patients treated with pre-operative radio(chemo) therapy followed by surgery depending on response. Methods: Data was obtained by retrospective case record review for 55 patients diagnosed with stage I to III resectable rectal cancer, using the TNM7 classification 3, between 2013-2017. All patients received pre-operative radiotherapy, in the form of short course radiotherapy (5X5 Gray) or long course chemoradiotherapy (45Gray in 25 fractions with Concurrent capecitabine), at Castle Hill Hospital, UK. Surgery was undertaken in eligible patients with total mesorectal excision (TME). Data was collected on time to surgery, radiological and pathological response and rate and site of recurrence. Data for recurrence was followed up to December 2017. Results: Patients had a median age of 66 years (range 36-86) and a male predominance (65% male vs 35% female). The majority of patients had stage III tumours (76%) compared to stage II (22%) and stage I (2%). Overall 75% patients had received long course chemoradiation and 25% short course radiotherapy. For long course chemoradiation, the median time to surgery was 12.3 weeks (8.6 - 32 weeks) and for short course it was 6 days (3-132 days). 96% of patients had completed radiotherapy as planned and of these 89% had proceeded to TME surgery. Reasons for not proceeding to surgery included a complete radiological response (2 patients), patient choice (1 patient), progressive disease (3 patients) and death (2 patients). Following treatment downstaging was observed in 36% of patients, determined either by surgical histology or by radiological response on MRI in those who did not proceed to surgery. A pathological complete response rate of 17% was observed in all patients who received combination treatment [pre operative (chemo)radiotherapy and surgery]. In patients who received long course chemoradiotherapy and surgery the pathological complete response had improved to 22%. The overall rate of recurrence (local and distant) at 3 years was 31%. This include 7 patients who had experienced distant recurrence immediately following radio(chemo) therapy with 3 of the 7 not proceeding to surgery. Overall distant only recurrence was observed in 24% patients, local out of field recurrence in 2% and local in-field recurrence in 5% of patients at 3 years. Of note, there were involved surgical margins in 2 of the 3 patients who developed local in-field recurrence. Conclusion: This retrospective review shows that pathological complete response rates are in keeping with previously published results and the rate of in-field recurrence is small in number. Hence, future strategies should concentrate on preventing distant recurrence, which is the main site of treatment failure.