Online

ESTRO 2020

Session Item

Clinical track: Lower GI (colon, rectum, anus)
9306
Poster
Clinical
23:00 - 23:00
Intensity-modulated radiotherapy treatment of anal cancer: single-institution outcomes
PO-1101

Abstract

Intensity-modulated radiotherapy treatment of anal cancer: single-institution outcomes
Authors: Scott|, Emily(1)*[emily.scott5@nhs.net];Kar|, Arunansu(1);Ariyaratne|, Hemal(1);
(1)Royal Free London NHS Foundation Trust, Clinical Oncology, London, United Kingdom;
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Purpose or Objective

To evaluate local control and survival in patients with localised anal cancer treated with intensity-modulated radiotherapy (IMRT) and concurrent chemotherapy.

Material and Methods

We retrospectively reviewed clinical records of patients treated with radiotherapy for anal cancer between April 2014 and September 2019 in a tertiary referral centre in the United Kingdom. All patients had biopsy-confirmed squamous cell carcinoma staged according to TNM 7. IMRT was planned on Pinnacle® TPS and delivered on a Varian® linac platform. Patients received concurrent chemotherapy unless contraindicated.

Results

83 patients had radiotherapy for anal cancer, with 76 included in the analysis. Patients excluded had non-IMRT or palliative treatment. 66% of patients were female. Median age was 62 years (range 28-90 years).    

The percentages of patients with T1, T2, T3 and T4 disease were 21%, 30%, 29% and 19% respectively. The percentages of patients with N0, N1, N2 and N3 disease were 44%, 22%, 16% and 17% respectively. Most patients had moderately differentiated histological grade (64%). Seven patients had basaloid subtype. 

The radiotherapy treatment schedule was 50.4 Gy in 28 fractions to involved regions. 40 patients (53%) with higher stage disease had simultaneous integrated boost to primary to 53.2 Gy in 28 fractions. 4% of patients received 41.4 Gy in 23 fractions as part of the PLATO clinical trial for low-risk disease. 

13% of patients had a defunctioning stoma prior to radiotherapy. 80% of patients received concurrent mitomycin C and capecitabine. Capecitabine alone (3%) or mitomycin C/5-FU (1%) were used infrequently. 16% of patients did not have chemotherapy. 8% started on a reduced dose of chemotherapy due to co-morbidities, and 11% had reduced dose intensity during treatment. Reasons for chemotherapy interruption included thrombocytopaenia, renal impairment and skin toxicity. There was no Grade 4 toxicity. 

Median follow-up was 16 months (range 1-61 months). Nine patients (12%) had local recurrence. Seven of these patients had T3/4 disease or nodal involvement. Three did not receive chemotherapy during treatment. Five patients with local recurrence were successfully treated with salvage surgery, while the others declined or were not fit for surgery. The rate of metastatic progression was 13%, and all these patients had T3/4 disease or nodal involvement at presentation. For the whole cohort, 12-month overall survival was 88% and 24-month overall survival was 84%.

Conclusion

IMRT with concurrent chemotherapy was well tolerated and resulted in very good local control and overall survival, despite a high proportion of stage III disease in this cohort. Local and distant recurrences were associated with advanced stage at presentation.