Secondary Tumors After Urinary Diversion

Radiation exposure in pediatric videourodynamics: An evaluation of safety in comparison to voiding cystourethrogram

INTRODUCTION

Children with spina bifida (SB) undergo a videourodynamic study (VUDS) or urodynamic study and voiding cystourethrogram (VCUG). A standardized protocol for imaging during a pediatric VUDS has not been established. Our aim is to quantify radiation exposure and establish a baseline for children with spina bifida (SB) undergoing VUDS in current practice at our institution.

METHODS

This is a retrospective study from 2013 to 2020 of consecutive pediatric SB patients undergoing VUDS by a single provider. Patients were categorized into three groups based on age; group 1 (0-2 YR), group 2 (2-10 YR), group 3 (>10 YR). Radiation data was reported as mean air kerma (AK), dose area product (DAP) and exposure time (seconds). Effective dose (ED) was calculated based on radiation quantity (Air Kerma, AK) and organ sensitivity. The lifetime attributable risk (LAR) was calculated based on AK and a risk coefficient. Data points calculated for patients undergoing VUDS were then compared to age matched institutional VCUG data in the same age groups.

RESULTS

398 patients undergoing VUDS met inclusion criteria and 262 independent patients underwent VCUG. ED increased with age in both VUDS and VCUG. All VCUG groups were found to have a higher ED than VUDS. The LAR for VUDS groups 1-3 was 0.001, 0.002, and 0.006, respectively. Reported in percentages, there is a 0.1%, 0.2%, and 0.6% chance, respectively, of age groups 1, 2 and 3 developing cancer as a result of the radiation exposure from a VUDS.

DISCUSSION

Our study found that ED was low across all age groups for VUDS, comparing favorably to the VCUG groups. VCUG was selected as a benchmark comparison for its diagnostic similarities and, at times, overlapping indications. Few studies have described ED with respect to VUDS or extrapolate the ED of VUDS into LAR in the pediatric population. We recognize that we have not determined the true ED of the gonads and bladder, rather we have overestimated, as the data is based on an international reference point proximal to the exposed individual. However, LAR was calculated for each age group and revealed that patients are at a negligible increased risk of developing malignancy secondary to exposure compared to the general population.

CONCLUSION

Our current practice for pediatric VUDS has exhibited consistently low radiation exposure amongst all age groups. Moving forward, we have the foundation and flexibility to create an imaging protocol for pediatric VUDS, while taking more calculated steps toward incorporating ALARA, as low as reasonably achievable, principles. A protocol adhering to the ALARA principle could provide consistency across institutions and aid in multi-institutional studies.

Donor-derived duodenal adenocarcinoma of a bladder-drained pancreas allograft

The subset of the population that received bladder-drained allograft pancreata during peak utilization of the technique in the 1990s is approaching 20-30 postoperative years. This time frame is salient, as it parallels the time in which patients in the urologic literature develop adenocarcinomas after bladder reconstruction using gastrointestinal segments. We present the case of a 57-year-old simultaneous pancreas/kidney recipient who presented with microhematuria twenty-four years after transplantation and was found to have an adenocarcinoma of the duodenum of his failed, bladder-drained pancreas. After allograft pancreatectomy/duodenectomy, he remains disease-free eleven months postoperatively. As this patient population ages, practitioners should consider pathology of the donor duodenum and pancreas in recipients who present with gross or microscopic hematuria.

Secondary malignancy after urologic reconstruction procedures: a multi-institutional case series

Urinary diversion and reconstructive urologic procedures are most often performed by incorporating various intestinal segments into the urinary tract. Although the risk of malignancy, among other complications, is well recognized and occurs most frequently after ureterosigmoidostomies and cystoplasties, data on the histopathologic and immunohistochemical characteristics of these tumors are scant. This study aims to evaluate the clinicopathological features of secondary tumors arising after urologic reconstruction procedures. Eleven cases were identified among five collaborating academic institutions. The average age was 51.7 years, and the M:F ratio was 8:3. Surgical procedures included 7 ileal conduits, 2 gastrocystoplasties, 1 augmentation cystoplasty not otherwise specified (NOS), and 1 Indiana pouch. Median time from reconstruction to malignancy was 36 years. Malignancy included adenocarcinoma in 10 patients (intestinal type in 6, gastric in 2, signet-ring cell in 1, undetermined type after neoadjuvant treatment in 1) and squamous cell carcinoma in 1. By immunohistochemistry, the adenocarcinomas were CK7 (45%), CK20 (89%), CK903 (78%), CDX2 (89%), SATB2 (67%), and beta-catenin (100%) positive. GATA-3 was negative in all cases. Pathologic stage was T1 (30%), T2 (40%), T3 (20%), and T4 (10%). Regional lymph node and distant metastasis were present in 60% and 20%, respectively. Treatment included multimodality therapy in most patients. On follow-up (mean, 27.4 months), 2 patients were dead (1 of disease), 3 were alive with disease, 4 were alive without disease, and 2 were lost to follow-up. Secondary malignancy arising within urologic reconstruction is rare, most frequently has adenocarcinoma morphology, presents late, and behaves aggressively.

Urinary diversion after pelvic exenteration for gynecologic malignancies

Pelvic exenteration combines multiple organ resections and functional reconstruction. Many techniques have been described for urinary reconstruction, although only a few are routinely used. The aim of this review is to focus beyond the technical aspects and the advantages and disadvantages of each technique, and to include a critical analysis of continent techniques in the gynecologic and urologic literature. Selecting a technique for urinary reconstruction must take into account the constraints entailed by the natural history of the disease, patient characteristics, healthcare institution, and surgeon experience. In gynecologic oncology, the Bricker ileal conduit is the most commonly employed diversion, followed by the self-catheterizable pouch and orthotopic bladder replacement. Continent and non-continent diversions present similar immediate and long-term complication rates, including lower tract urinary infections and pyelonephritis (5-50%), ureteral stricture (3-27%), urolithiasis (5-25%), urinary fistula (5%), and more rarely, vitamin B12 deficiency and metabolic acidosis. Urinary incontinence for the ileal orthotopic neobladder (50%), stoma-related complications for the Bricker ileal conduit (24%), difficulty with self-catheterization (18%) for the continent pouch, and induction of secondary malignancy for the ureterosigmoidostomy (3%) are the most relevant technique-related complications following urinary diversion. The self-catheterizable pouch and orthotopic bladder require a longer learning curve from the surgical team and demand adaptation from the patient compared with the ileal conduit. Quality of life between different techniques remains controversial, although it would seem that young patients may benefit from continent diversions. We consider that centralization of pelvic exenteration in referral centers is crucial to optimize the oncologic and functional outcomes of complex ablative reconstructive surgery.

Adenocarcinoma of an ileal conduit developing 8 years after cystoprostatectomy for locally advanced prostate carcinoma

A 70-year-old patient was treated in September 2017 for a malignancy in an ileal conduit (IC) which he received in 2009 for the treatment of prostate cancer. The tumour was found incidentally during a routine sonography. A CT scan revealed a mass near the IC. An endoscopy with biopsies showed an intraepithelial neoplasia of the ileal mucosa in the IC. We performed a segmental ileal resection. Histological findings revealed an ileal adenocarcinoma. The postoperative course was uneventful. The patient has remained alive without tumour recurrence up to the most recent negative CT screening in April 2019. Secondary malignancies after urinary diversions are a well-known complication, including procedures using small bowel parts for the urinary diversion. Adenocarcinomas arising in an IC are rarely described in literature. Concerning said tumour entity, surgical removal is often recommended. There is no evidence for the success of chemotherapy or radiation due to insufficient clinical trials. When diagnosing a mass in an IC, a secondary malignancy should be taken under consideration.