Saturday, July 13, 20248:00 AM - 9:00 AMMSOR01 Presentation Time: 8:00 AM

Purpose

Although rectal cancers are traditionally treated with surgical excision, more patients are opting for alternatives and choosing an organ preservation approach instead.Studies demonstrate that a radiotherapy boost improves rates of complete response with low rates of regrowth.Contact X-Ray brachytherapy (CXB) often referred to as Papillon technique, accomplishes dose escalation in the treatment of low rectal cancer.This involves inserting an X-Ray tube through the anus and placing it in contact with the tumour. The OPERA study published in 2023, showed that for tumours <3cm in size, combination treatment of external beam radiotherapy(EBRT) and CXB boost achieves a 97% success rate of organ preservation within a 3-year follow up. St Luke's oncology Center is one of the 4 centers in the UK that specialise in Papillon brachytherapy. The purpose of this study was to report the toxicity of CXB; both alone and in combination with external beam radiotherapy (EBRT) as documented by patients themselves as a subset of our national colorectal patient reported outcome measures (PROMs) study CITRuS (Complex Intervention protocol Toxicity in patients following Radiotherapy or Surgery for colorectal cancer).

Materials and Methods

26 patients treated with CXB alone or in combination with EBRT were identified via the CITRuS platform(506 registered, 288 consented). 22 received CXB with EBRT (combined treatment) and 4 patients CXB alone. The CXB patients received no other treatment prior to CXB. The questionnaires investigated bowel, urinary and sleep symptoms as well as weight monitoring. The data presented reflect answers to the baseline questionnaires and up to the first 8 months post completion of treatment.This study is ongoing.

Results

Of the 22 patients who received the combined treatment, 19 completed the baseline questionnaires, 11 completed 4-5 months, 8 completed the 7-8 months period. In this group,two patients reported mild increase in their pain by the 5th month post treatment. GI: Six patients reported a slight increase in mucous from baseline to 5 months whereas three patients documented increase in nocturnal bowel symptoms. Futhermore, compared to baseline, patients reported an increase in flatulence, solid and liquid stool incontinence as well as their bowel motions affecting their lifestyle, at 5 months post treatment(16%).In the Papillon alone group, pain,blood,mucous and nocturnal symptoms were significantly improved by 5 months. Flatulence seems to be more predominant in this group around the 4-5 month period post treatment. GU:There was a definite peak in urine frequency in the combined group. The Papillon alone group showed improvement of all urinary symptoms by 4 months. Sleep:Both groups demonstrated a significant impact on their sleep quality and energy during the day by 8 months post treatment (75-88%). Weight: The weight picked up in both groups by 3 months post completion of treatment.

Conclusions

Patients tend to favour an organ preservation approach due to perceived quality of life benefits, yet there is very little evidence that can be presented to aid decision making in this situation. It is important to have a guided approach in what toxicity patients may experience and at what time points after completion of their treatment. This initial analysis of a small cohort provides early data. As expected, the patients in the combined treatment group had more symptoms that continued for several months after their treatment. It is important that CXB is considered as a stand-alone treatment for patients with low risk T1N0 disease. The study also demonstrates the importance of PROMs questionnaires, their immense value in patient management and how such results can help guide improved decision making with a better targeted approach in helping these patients cope with their symptoms.