Elective nodal radiotherapy with a gapless radiation field junction for oligorecurrent prostate cancer after previous radiotherapy

•A gapless junction of an elective nodal radiotherapy field after previous radiotherapy is feasible.•A cumulative maximum dose (Dmax-cum) ≤ 95 Gy and a maximum cumulative dose in 1 cc (D1cc-cum) < 90 Gy were used as dose constraints.•This approach is safe without additional acute or late grade 3 toxicity.