Bladder Adjuvant RadioTherapy (BART): Acute and Late Toxicity from a Phase III Multicentre Randomized Controlled Trial: Acute and late toxicity in BART RCT
Mené sur 153 patients atteints d'un carcinome urothélial de la vessie avec envahissement musculaire et à haut risque de récidive, cet essai multicentrique évalue la toxicité d'une radiothérapie après une cystectomie radicale et une chimiothérapie
Purpose: To report toxicity from the multicentre phase III randomized trial of Bladder Adjuvant Radiotherapy (BART) after radical cystectomy (RC) and chemotherapy in high-risk muscle-invasive bladder cancer (MIBC). Materials/Methods: Patients with non-metastatic urothelial MIBC with ≥1 high-risk feature after RC: pT3-4, pN1-3, nodal yield <10, positive margin, or ≥cT3 downstaged with neoadjuvant chemotherapy; were randomized 1:1 to observation (Obs) or adjuvant radiotherapy (RT) at 4 centres, stratified by pN stage (N0, N+) and chemotherapy (neoadjuvant, adjuvant, none). Stoma-sparing IG-IMRT 50.4Gy/28# was prescribed to the cystectomy bed and pelvic nodes. Acute toxicity (≤3 months of RT/randomization) and late toxicity were assessed per protocol using CTCAE v5.0. Patients progressing within 3 or 6 months of randomization were excluded from acute or late toxicity analysis respectively. Results: BART trial enrolled 153 patients (Obs=76, RT=77). About half (49%) had pN+. Nearly 90% received chemotherapy (70% neoadjuvant; most commonly gemcitabine plus cisplatin). In the RT arm, 63/77 completed radiotherapy per protocol with no toxicity-related RT termination. Of the 134 patients analyzable for acute toxicity, no difference was observed in grade 3 (Obs 4.2% vs RT 1.6%, p=0.34). Grade 2 effects were higher with RT (17.5% vs 1.1%, p<0.001), mainly diarrhea/enteritis or proctitis. Late toxicity was analyzable for 104 patients (Obs=57, RT=47) with median follow up of 27 months. Grade 3-4 toxicity were about 10% (Obs 10.5% vs RT 8.4%, p=0.62), and cumulative late grade 2+ toxicity was similar in both the groups (17.5% vs 23.3%, p=0.27). Conclusion: In the largest trial of adjuvant radiotherapy for high-risk urothelial MIBC, severe acute and late toxicity were low and similar with observation or radiotherapy. The oncological outcomes are awaited.