Radiation-associated retroperitoneal fibrosis causing obstructive uropathy after pelvic chemoradiotherapy for rectal cancer: a case report
Imane Benmoussa, Latifa Doublali, Rim Alami, Mouna Bourhafour, Souha Sahraoui, Amal Mrani AlaouiAbstract
Introduction:
Radiation-associated retroperitoneal fibrosis (RPF) is a rare late complication of pelvic radiotherapy that may cause ureteric obstruction, hydronephrosis and renal impairment. Its radiological presentation may mimic tumour recurrence, making diagnosis challenging. We report a case of radiation-associated RPF following pelvic chemoradiotherapy for rectal adenocarcinoma, highlighting its diagnostic implications.
Case:
A 59-year-old man underwent total neoadjuvant treatment, pelvic chemoradiotherapy (46 Gy with a 4 Gy boost and concurrent capecitabine) and curative surgery. Eleven months after radiotherapy, surveillance computed tomography demonstrated retroperitoneal soft tissue consistent with probable radiation-associated fibrosis, associated with renal dysfunction. The patient subsequently developed severe right ureterohydronephrosis requiring percutaneous nephrostomy. Pelvic magnetic resonance imaging and positron emission tomography excluded locoregional recurrence and metastatic disease, supporting benign radiation-associated fibrosis. Follow-up imaging demonstrated stable RPF without tumour recurrence.
Discussion:
This case illustrates the importance of considering radiation-associated RPF in patients presenting with delayed obstructive uropathy after pelvic irradiation. Multimodal imaging was essential to distinguish benign fibro-inflammatory changes from recurrent malignancy and guide management.
Recommendations:
Radiation-associated RPF should be considered in patients with unexplained renal dysfunction or hydronephrosis after pelvic irradiation. Early recognition, multidisciplinary assessment, urinary decompression and long-term imaging surveillance are essential to optimise patient outcomes.