Presentation of UTO can vary with no symptoms to pain and hematuria depending on the type and duration of obstruction . For example, patients with chronic hydronephrosis may be completely asymptomatic with incidental finding of a rise in serum creatinine. On the other hand, patients with acute obstruction due to kidney stones or bladder cancers may have pain, dysuria, and hematuria. Anuria or even oliguria may not be present unless the obstruction is complete. Therefore, “a good urine output” does not exclude urinary obstruction. An inexpensive and least invasive investigation that can virtually rule out an obstruction is a careful ultrasonic examination of the kidney ureters and bladder, especially if a repeat one after 12–24 h is found to be normal. Bilateral urinary obstruction often results in decreased urinary output while unilateral obstruction would not .

Initially, a detailed history concerning pain, acuity of symptoms, urinary complaints, infections, and hematuria combined with a physical exam can provide significant information about the cause of the rise in creatinine. Imaging will further confirm any suspicion of obstruction . The different imaging modalities, commonly used to diagnose UTO, are ultrasound, CT, nuclear medicine, and magnetic resonance imaging (MRI).

Non-dilated obstructive uropathy is not a common phenomenon in the general population (4 %); however, in the cancer population there is an increased incidence and approximately 60 % are associated with an intrapelvic malignancy. When a patient with renal failure presents with the associated findings of an intrapelvic or retroperitoneal tumor, it is imperative that obstructive uropathy be ruled out, even in the absence of dilatation [10, 11]. Ultrasound is usually the first choice due to its availability, and no exposure to radiation (Fig. 15.2). The false-positive rate (nonobstructive hydronephrosis) is between 10 and 20 % and is not as effective in determining the etiology and location of obstruction. A retrograde pyelogram or an antegrade pyelogram may be a better modality when all other etiologies of renal failure are ruled out. A possible mechanism of nondilatation of the UTO is encasement of the ureters in tumor or fibrous tissue, abnormal ureteral peristalsis, urinary debris, and ureteral edema .

Regardless of the actual mechanism, MRI may be an alternative to CT if indicated. Percutaneous nephrostomy (PCN) and antegrade urography are utilized after ureteral obstruction is detected in order to relieve the obstruction, and may be done to establish a diagnosis of obstruction among patients who are at very high risk for obstruction and who have a nondiagnostic CT or ultrasound [12]. While some centers use nuclear medicine scan, they are not standard of care to diagnose urinary obstruction since the diagnosis can simply be made with an ultrasound in majority of the cases. In addition, nuclear scans are less useful when renal function is diminished because of delayed isotope excretion and diuretic resistance.

In cancer patients, decompressing the urinary tract is crucial to prevent chronic damage to kidney . Once a decision is made to decompress the obstruction, it is preferable to do that at the earliest convenience. However, an emergency decompression may not be necessary especially over the weekend or in the after-hours if the kidney function, serum electrolytes, and patient’s clinical conditions such as volume status are stable. However, it is important to balance patient quality of life, need for long-term renal preservation and risk of complication should be taken into account in the setting of a poor prognosis or very short life-expectancy. Treatment of UTO usually aims to eliminate the obstruction by surgery, instrumentation (e.g., endoscopy, lithotripsy), or drug therapy (e.g., hormonal therapy for prostate cancer). Since, surgery is not possible in all cases, nephrostomy or ureterostomy can help to decompress the urinary tract . PCN is currently the preferred supravesical diversion because of its minimal morbidity and mortality [13]. A ureteral stent or PCN usually becomes permanent in patients with advanced cancers because they are not curable [14].

UTO in cancer patients due to tumor involvement can be alleviated by introducing indwelling Foley’s catheters, PCN, ureteral stents in conjunction with undergoing treatments for the underlying malignancy to help reduce the tumor burden and hopefully resolve the obstruction.

Some of the other etiologies of UTO in the cancer population are retroperitoneal fibrosis (Ormond’s disease), which is characterized by the presence of inflammatory and fibrous retroperitoneal tissue that often encases the ureters or abdominal organs [15]. It is described as idiopathic or secondary in nature. Secondary causes that are relevant to our cancer population are as follows :