1849P Safety and effectiveness of palliative chemotherapy (CTX) for patients (pts) with malignant bowel obstruction (MBO)

Abstract

MBO is associated with a high disease burden and a dismal prognosis in cancer pts. Although CTX is frequently administered to pts with MBO, its benefit remains unknown. The present study assessed the outcomes of pts who received CTX as part of MBO treatment. For this retrospective cohort study, data was extracted from electronical records of pts hospitalized due to MBO at a tertiary cancer center from 2009 to 2019. Eligible pts were not candidates to surgery and received CTX for the malignancy causing MBO, as well as supportive measures to manage MBO according to local guidelines. Primary objective was to assess pts outcomes after CTX; secondary objectives were pts outcomes after MBO diagnosis, rates of intestinal function recovery and re-obstruction, and rates of grade ≥3 toxicities after CTX. The primary endpoint was overall survival (OS). Survival was estimated by Kaplan–Meier method, and comparisons performed with log-rank test. A total of 167 pts were included: median age was 55 years (18−81), 55.7% were females, 91% had an ECOG-PS ≥2, 75.4% had gastrointestinal primary tumors, and 70.1% had no previous systemic treatment. Median time from cancer diagnosis to MBO was 16 weeks (0-972.4), and median length of hospitalization after CTX was 2 weeks (0.1-13.6). Overall, a total of 159 deaths were observed, with a median OS of 4.4 weeks (95% confidence interval [CI], 3.4-5.5) after CXT administration, and 5.6 weeks (95% CI, 4.6-6.5) after MBO diagnosis. Treatment line, ECOG-PS and primary tumor did not impact OS. Intestinal function recovery was observed in 86 pts (51.5%) after CTX, out of whom 22 (25.5%) had a re-obstruction. Pts who recovered intestinal function had a longer OS when compared to those who did not (10 weeks vs. 2.1 weeks; p<0.001). Hospital discharge was possible in 51.5% of the pts, and it was significantly correlated with intestinal function recovery (p<0.001). Grade ≥3 toxicities occurred in 26.9% of the pts after CTX. MBO was associated with a poor prognosis in this mostly treatment naive population. The administration of CTX yielded a significant risk of toxicities, whereas it may provide a modest benefit of questionable clinical relevance in this scenario.