Intraoperative electron-beam radiotherapy and ureteral obstruction

To quantify the risk of ureteral obstruction (UO) after intraoperative electron-beam radiotherapy (IOERT).

One hundred forty-six patients received IOERT of 7.5 to 30 Gy to 168 ureters; 132 patients received external radiotherapy.

Follow-up ranged from 0.01 to 19.1 years (median, 2.1 years). The rates of clinically apparent type 1 UO (UO from any cause) after IOERT at 2, 5, and 10 years were 47%, 63%, and 79%, respectively. The rates of clinically apparent type 2 UO (UO occurring at least 1 month after IOERT, excluding UO caused by tumor or abscess and patients with stents) at 2, 5, and 10 years were 27%, 47%, and 70%, respectively. Multivariate analysis revealed that the presence of UO before IOERT (p < 0.001) was associated with an increased risk of clinically apparent type 1 UO. Increasing IOERT dose (p < 0.04) was associated with an increased risk of clinically apparent type 2 UO. UO rates in ureters not receiving IOERT at 2, 5, and 10 years were 19%, 19%, and 51%, respectively.

Risk of UO after IOERT increases with dose. However, UO risk for ureters not receiving IOERT was also high, which suggests an underlying risk of ureteral injury from other causes.