Online

ESTRO 2020

Session Item

Clinical track: Lower GI (colon, rectum, anus)
9306
Poster
Clinical
23:00 - 23:00
Impact of fractionation on the treatment of squamous cell anal cancer: a dual-institution experience
PO-1107

Abstract

Impact of fractionation on the treatment of squamous cell anal cancer: a dual-institution experience
Authors: Vernaleone|, Marco(1)*[mvernale@hotmail.com];Bonomo|, Pierluigi(2);Meduri|, Bruno(1);Caramia|, Giorgio(2);Aluisio|, Giovanni(1);Visani|, Luca(2);Desideri|, Isacco(2);Becherini|, Carlotta(2);D'Angelo|, Elisa(1);Livi|, Lorenzo(3);Lohr|, Frank(4);
(1)Azienda Ospedaliero-Universitaria di Modena, Oncology Department - Radiation Oncology Unit, Modena, Italy;(2)Azienda Ospedaliero-Universitaria Careggi, Radioterapia Oncologica, Firenze, Italy;(3)Azienda Ospedaliero-Universitaria Careggi- University of Florence, Radioterapia Oncologica, Firenze, Italy;(4)Università degli Studi di Modena e Reggio-Emilia, Oncology Department - Radiation Oncology Unit, Modena, Italy;
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Purpose or Objective

It is known that a prolonged overall treatment time (OTT) has a detrimental effect on outcome for non-metastatic squamous cell anal cancer (SCAC) patients. Aim of our work was to evaluate the impact of an accelerated radiotherapy regimen (AF) on tolerability and efficacy in comparison with conventional fractionation (CF).

Material and Methods

Between March 2014 and June 2018, patients affected by non-metastatic SCAC treated with Tomotherapy in two different institutions were considered for our study. A frequency-matched cohort analysis was performed to balance patients’ characteristics between the two groups (AF and CF): median age, disease stage and administration of concurrent chemotherapy were the considered variables. Most used treatment schedules for the two groups were 55 Gy/2.2 Gy/fx vs 54 Gy/2 Gy/fx to high risk PTV, 45 Gy/1.8 Gy/fx vs 45.9/1.7 Gy/fr to low risk PTV in 25 and 27 fractions in the AF and CF cohorts, respectively. Acute toxicity was scored according to NCI – CTCAE v. 4.03. Time to progression (TTP) and overall survival (OS) were calculated from the end of treatment to the date of first local or distant recurrence and to the date of death from any cause, respectively. Moreover, time to colostomy (TTC) was calculated, as the time from the end of treatment to the salvage colostomy.

Results

Overall, 94 patients were included; 46 (49%) and 48 (51%) received a CF and AF radiotherapy treatment, respectively. Patients’ characteristics were well matched between the two cohorts: the median age was 66,1 and 66,5 years, and the incidence of stage III was 56,5% and 52% (TNM AJCC 7th ed.) in CF and AF groups, respectively; while, concurrent chemotherapy was prescribed to 86,7% of CF patient and 70,8% of AF ones, with mytomicin C-5FU as the most common regimen. The rate of non-hematologic acute toxicity ≥ G2 (radiation dermatitis, diarrhea and cystitis) were 73% vs 63%, 18% vs 31%, and 11% vs 2% in CF and AF cohorts, respectively. In terms of overall non-hematologic acute toxicity, the ≥ G2 rate was 80% and 69%, respectively. For all safety outcomes, no statistically significant difference could be found between the two groups. With a median follow-up of 30 months, 2-year TTP was 76,3% vs 81,7%, while OS was 89,6% vs 93,6% in CF and AF cohorts, respectively, with no statistically significative differences.
Moreover, 2-year TTC was 86% for CF vs 95,8% for AF (p=0,24).

Conclusion

This preliminary analysis of our dual-institution experience does not show any statistically significant differences on safety nor efficacy between a mild accelerated hypofractionation and a conventional regimen. A longer FUP is needed to confirm the data and to evaluate any late toxicity.