Nodal failure after chemo-radiation and MRI guided brachytherapy in cervical cancer: Patterns of failure in the EMBRACE study cohort

•Nodal failure rate after chemo-radiation and MRI guided BT is 11%.•Nodal failure rates for the N− and N+ group were 7 and 16%•Complete remission after treatment was seen in 95% of N+ patients.•Nodes at diagnosis were mainly located in the pelvis, nodal failures more often in PAO.•Forty-one percent of nodal failure patients had failure outside the treated volume. To investigate the patterns of nodal failure in patients enrolled in the international multicentre EMBRACE study. Nodal disease at diagnosis (N−, N+) and nodal failure were analysed per region (NF) (pelvic (parametrial, common iliac, internal/external iliac), inguinal and para-aortic (PAO)) in 1338 patients. Treatment consisted of chemo-radiation and MRI guided brachytherapy. PAO radiotherapy and/or nodal boost was left to the treating centre. At time of diagnosis 52% of patients had pathologic nodes. Frequency analyses were performed in relation to patient, primary tumour and nodal disease characteristics, and treatment related factors. Median follow up was 34 months and 83% of NF occurred within 24 months. At diagnosis 99% of the N+ patients had pathologic nodes in the pelvis and 14% in the PAO. NFpelvic and NFPAO were reported in 55% and 68% of patients with NF, respectively. Overall NF was reported in 152 patients (11%); 7 and 16% for N- and N+ patients. Of the patients with NF, 41% were located outside the elective target (39% PAO), 40% inside and 35% inside the nodal boost target. Twelve percent of N+ patients that received a nodal boost had a NF inside the nodal boost target. Within the EMBRACE study cohort the overall number of patients developing nodal failure is low, significantly lower for N− compared to N+ patients. Pathological nodes at diagnosis are mainly located in the pelvis, whereas nodal failures are more often reported in the PAO region. About 40% of all nodal failures were reported outside the treatment targets.