Session Item

The main purpose of this study was to evaluate the radiotherapy (RT) toxicity patterns in older patients (>65 years-old) with rectal cancer.

This retrospective study was based on RT Department electronic health records collected on February 2019. This study was approved by the institutional ethical review board. All patients with rectal cancer treated with RT between January 2013 and December 2017 were included (n=291). Patient, tumour, and treatment characteristics were collected. Acute toxicity data related to asthenia, anorexia, pain, insomnia, haematological, any urinary symptoms, nausea/vomiting, diarrhoea, constipation, rectal incontinence, bleeding, and urgency was registered. Acute low gastrointestinal, genitourinary, and skin toxicity were graded according with RTOG. Late toxicity patterns were evaluated through fibrosis, urinary symptoms, diarrhoea, constipation, sexual issues, and rectal incontinence, bleeding and urgency. Primary descriptive toxicity analysis was followed by comparison (Chi-square test) between older patients (>65 years-old) and younger, for the most frequent toxicities. The IBM SPSS v.25 software was used for statistical analysis.

Patient, tumour, and treatment characteristics are listed on Table 1. Median follow-up time was 29 months (IQR 28). Most frequent acute toxicities in the cohort were asthenia (4.5%), pain (20.3%), haematological (3.8%), urinary symptoms (16.2%), constipation (8.2%), diarrhoea (35.4%), and rectal incontinence (3.4%) and bleeding (18.2%). There were no reported cases of anorexia, insomnia, or nausea/vomiting. Patients over 65 y/o had significantly higher rates of urinary symptoms (p=0.026) and haematological toxicity (p= 0.026). They also tend to have more frequent diarrhoea (p=0.245), pain (p=0.129), and rectal incontinence (p=0.056), although not statistically significant. Subsequent classification of the urinary symptoms accordingly with GU-RTOG, showed no patients with grade 3, and non-significant difference between age groups (p=0.576). In relation to late toxicities, the most prevalent in this cohort were fibrosis (19.2%), urinary symptoms (11.7%), diarrhoea (18.2%), rectal incontinence (3.8%), constipation (2.7%) and sexual issues (5.5%). For 19 patients the data related to late toxicity was missing. Sub-group analysis comparing older adults with younger ones showed no significant differences on late toxicity rates.

In this study, older patients had a higher rate of acute urinary symptoms, in comparison with younger ones, but there was no records of grade 3 genitourinary acute toxicity (RTOG). It was found a significant higher rate of acute haematological toxicity and a trend to more frequent diarrhoea and rectal incontinence. Regarding late toxicity patterns there were no significant discrepancy noted between age-groups.