ABSTRACT
Introduction The management of patients with ureteral obstruction in advanced cancer can be difficult. Metastases from primary malignancies anywhere can spread to the retroperitoneum and lead to ureteral obstruction. Secondary involvement of the retroperitoneum by malignant tumours occurs either by direct extension of the adjacent malignancy or by metastasis to the retroperitoneal lymph nodes. Tumours that spread to the retroperitoneum by direct extension usually involve the pelvic part of the ureter. The tumours may simply compress the ureteral wall, but they can also invade the entire ureter. Metastatic tumours involving the retroperitoneum and the periureteral lymphatic nodes tend to produce obstruction, which may be limited or quite extensive in area.1 Tumours of varying origin can progress in this way; they include metastases from carcinomas of the breast, stomach, lung, pancreas, lymphoma and colon.2,3 Tumours arising from pelvic structures can be similarly involved; typically, these include tumours of the bladder or prostate, the cervix, sigmoid colon and rectum. Theoretically, any secondary tumour mass spreading to the retroperitoneum can advance upon the ureter with subsequent obstruction and hydro-or pyonephrosis.4,5 Ureteral obstruction may occur within 2 years of the primary diagnosis in 60-70% of patients, but it may occur up to 20 years later,6 or may be the first sign in gynaecological cancer.3 Sometimes the decrease in urine output is not suspected until the patient develops signs of uraemia due to obstruction of both ureters or anuria becomes manifest.2,3 The obstruction usually can be seen in the distal or pelvic part of the ureter, although it can occur anywhere and may be located at multiple sites.
