ESTRO 2023 - Abstract Book

S1127

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ESTRO 2023

Conclusion More than a half of patients with rectal cancer may be cured without needing surgery by using the FOREST protocol. The presence of affected margins negatively influences these outcomes. In addition, we have abandoned short regimen because a lower success rate and we have implemented an integrated boost to improve the results. Limitations in terms of small sample and short follow-up made further studies needed to reach definitive conclusions.

PO-1398 Long term urinary function after preoperative radio(chemo)therapy in locally advanced rectal cancer

L. Riber 1 , A.L. Appelt 2 , L. Fokdal 1 , H.S. Rønde 3 , B.M. Havelund 1

1 Vejle Hospital, University Hospital of Southern Denmark, Department of Oncology, Vejle, Denmark; 2 University of Leeds, Leeds Institute of Medical Research at St James's, Leeds, United Kingdom; 3 Aarhus University Hospital, Danish Centre for Particle Therapy, Aarhus, Denmark Purpose or Objective Standard treatment of locally advanced rectal cancer include a multimodality treatment approach with neoadjuvant radio(chemo)therapy to the tumour and elective pelvic lymph nodes followed by total mesorectal excision (TME). Due to the multimodality approach, bladder morbidity may be a point of concern; but detailed reports, including time course of symptoms, are few. We conducted a prospective cohort study (research ethics committee number S-20110021) of long term patient reported (PRO) and healthcare professional reported toxicity after pre-operative intensity modulated radiotherapy (IMRT) and TME surgery. We here report data on urinary morbidity after treatment. Materials and Methods A total of 56 patients were included in the period from July 2011 to April 2014. All patients were treated with pre-operative long course radiotherapy, using IMRT optimized to spare bladder & bowel, as well as concomitant Ufteral or Capecitabine. Morbidity (CTCAE v. 4.0, by oncologists or cancer nurses) and PRO (EORTC-QLQ-CR29) was prospectively registered at baseline (BL), end of treatment (EoT), and during each follow up visit for 5-years (for a total of 13 assessments). Proportion of evaluable patients reporting each symptom score at each timepoint was summarized. Change from BL in average cohort scores was evaluated using the wilcoxon signed rank test, and statistically significant changes defined as p<0.05. Results Patient demographics and key bladder dose statistics are reported in Table 1. Median follow up was 92 (9-119) months, with 16 (29%) patients experiencing recurrence during the follow-up period. Urinary symptoms, as reported by patient and healthcare professional, at all timepoints are shown in Figure 1. The most frequent urinary symptoms were frequency, urgency and dysuria; with grade 2 prevalence rates of 3.3%, 3.0% and 0.0% at 3 years, and grade 1 prevalence rates of 36.7%, 27.0% and 3.0% at 3-years. The most frequent PRO endpoint was ‘frequency’, both during the day and during the night; with prevalence rates for ‘Quite a Bit’ of 52.2% and 30.4% at EoT (day: p<0.001 and night: p<0.001) and 19.4% and 8.3% at 12 months (day: p=0.417 and night: p=0.830). No grade 4 and 5 toxicity occurred and only limited grade 3 toxicity occurred regarding urinary incontinence. Table 1: