Impact of chemoradiotherapy for bladder cancer on pre-existing hydronephrosis and development of new hydronephrosis

Abstract

Background: Radical cystectomy is the recommended treatment in muscle-invasive bladder cancer patients with hydronephrosis. However, there is no literature on the impact of chemoradiotherapy on pre-existing hydronephrosis or the development of new hydronephrosis. This study aims to assess the incidence, aetiology, and management of hydronephrosis before and after chemoradiotherapy (CRT).

Materials and methods: Retrospective cohort study, including patients with muscle-invasive bladder cancer (MIBC) treated with CRT between 1 January 2014 and 5 December 2022. Patients with urethral urothelial carcinoma and with stage T1 were included if they received total bladder irradiation. Exclusion criteria were renal transplantation, ureteral reimplantation, sequential chemotherapy and radiotherapy, CRT as preoperative treatment, urinary diversion before CRT, transitioning to palliative radiotherapy, and sarcomatoid or signet ring cell carcinoma type. Patients were also excluded if no follow-up data was available. In this period 181 patients received CRT, after applying the exclusion criteria a total of 146 patients were eligible for evaluation. The main outcome was hydronephrosis, defined as any grade of dilatation of the renal pelvis with or without ureter dilatation, identified on any form of imaging.

Results: 146 patients were included, 27 with pre-existing hydronephrosis before CRT and 119 without. The mean age of the patients was 73 years (Standard deviation (SD): 8.59) and 74% was male. Hydronephrosis in patients with pre-existing hydronephrosis persisted after CRT in 74% (n = 20), with 44% (n = 12) receiving drainage. Of the patients without pre-existing hydronephrosis, 21% (n = 25) developed hydronephrosis, and 52% (n = 13) of the patients that developed hydronephrosis required drainage. Tumour was responsible for pre-existing hydronephrosis in 93% (n = 25) and for hydronephrosis after CRT in 22% (n = 6) with pre-existing hydronephrosis. In patients without pre-existing hydronephrosis, hydronephrosis was caused by a tumour in 11 out of 25 patients.

Conclusions: Pre-existing hydronephrosis persists after CRT for MIBC in ~ 75% of patients and ~ 20% of patients without pre-existing hydronephrosis develops hydronephrosis after CRT. Around half of these patients receive drainage. These findings may assist in counselling patients with pre-existing hydronephrosis regarding the potential outcomes following CRT.

Keywords: Bladder cancer; Bladder preservation; Bladder preserving treatment; Bladder-sparing treatment; Chemoradiotherapy; Concurrent chemoradiation; Hydronephrosis; Radiotherapy; Trimodality treatment.

Fig. 1

Overview of the components included in the nephron-sparing and bladder-sparing composite outcome. All patients with pre-existing hydronephrosis are analyzed for the nephron-sparing and for the bladder-sparing perspectives. Drainage, cystectomy and local MIBC recurrence at any location in the bladder are components of both COs. Additional components in the nephron-sparing CO are (1) a decrease in eGFR of ≥ 1 category and (2) the development of an atrophic kidney. The additional component of the bladder-sparing perspective CO is an eGFR < 30 ml/min/1.73 m². If any component of the perspective’s CO occurred in a patient, CRT was regarded as an unpreferred treatment choice in that patient. CO = composite outcome; CRT = chemoradiotherapy; eGFR = estimated glomerular filtration rate; MIBC = muscle-invasive bladder cancer

Fig. 2

Flow diagram depicting patient inclusion and reasons for exclusions. CRT = chemoradiotherapy

Fig. 3

Flow of Patients with hydronephrosis. Drainage and Kidney Function Before and After Chemoradiotherapy. (A) On the left the drainage before CRT is displayed in patients with hydronephrosis prior to CRT. In the middle, the present drainage after CRT (performed either before or after CRT), is displayed. On the right side the definitive treatment of hydronephrosis in patients with hydronephrosis prior to CRT is shown. (B) On the left side the patients are categorized into the kidney function groups according to their eGFR before treatment with CRT. On the right side, it is shown if the patients had hydronephrosis after CRT and in what kidney function category they were according to their final eGFR (see definitions). CRT = chemoradiotherapy; eGFR = estimated glomerular filtration rate

Fig. 4

Kaplan-Meier curves of the composite outcome-free survival for nephron-sparing and bladder-sparing perspectives. The composite outcome of the nephron-sparing perspective consisted of (1) drainage, (2) cystectomy, (3) muscle-invasive bladder cancer (MIBC) recurrence, (4) atrophic kidney and (5) a decrease in estimated glomerular filtration rate (eGFR) of one or more categories. The composite outcome of the bladder-sparing perspective consisted of (1) drainage, (2) cystectomy, (3) MIBC recurrence and (4) an eGFR of < 30 ml/min/1.73 m²

Fig. 5

Management strategy proposal for patients with pre-existing hydronephrosis. Patients should be counselled on both bladder-sparing and nephron-sparing treatment approaches. In cases where the patient expresses a preference for chemoradiotherapy (CRT) and meets the necessary criteria, a dimercaptosuccinic acid (DMSA) scan should be conducted to evaluate the relative function of the hydronephrotic kidney. In cases where the relative function is less than 10%, CRT can be performed without the need for drainage. However, it is imperative to discuss the risks of complications, such as infection, with the patient. In instances where the relative function is 10% or greater, drainage should be recommended and discussed with the patient. The patient may also opt for cystectomy instead of CRT, if deemed eligible, after the results of the DMSA scan indicate the need for drainage. In cases where drainage is necessary, a percutaneous nephrostomy tube is the preferred procedure, as it minimizes the risk of tumour spread within the urinary tract. In accordance with CRT, the management of the nephrostomy tube (permanent placement, removal, or conversion to a double-J stent) is contingent upon the persistence of hydronephrosis and the residual kidney function. CRT = chemoradiotherapy; DMSA = dimercaptosuccinic acid; MIBC = muscle-invasive bladder cancer