Follow-up after local treatment
Following local treatment for non-muscle-invasive bladder cancer, patients require regular monitoring. The baseline workup includes urinalysis, cytologic examination, and cystoscopy. In addition, the upper urinary tract must be evaluated for life every 1–2 years due to the risk of developing new tumors within it.
The main imaging challenge at this stage is the difficulty of differential diagnosis. Scarring and wall thickening after transurethral resection (TURBT), as well as the reaction to BCG therapy, can simulate recurrence. Diffusion-weighted MRI (DWI) demonstrates high accuracy in detecting disease relapse, achieving 100% sensitivity.
Monitoring after chemoradiotherapy and cystectomy
Imaging during neoadjuvant therapy aims to assess treatment efficacy prior to radical cystectomy. Changes in diffusion on DWI allow for early prediction of tumor response.
Following bladder removal, imaging surveillance protocols, such as EAU guidelines, include CT every 4 months in the first year, with gradually increasing intervals. The most frequent postoperative complication is anastomotic stricture. Benign strictures can be difficult to differentiate from recurrent tumors, although they occur much more frequently.
Assessment of response to systemic therapy
The efficacy of chemotherapy is evaluated by changes in the size of tumor lesions. According to RECIST 1.1 criteria, a partial response is defined as a decrease in the sum of lesion diameters by at least 30%, and progression as an increase of 20%.
Promising approaches include diffusion-weighted MRI and dynamic contrast-enhanced imaging. They can reveal changes in tumor perfusion and cellular density even before the tumor visibly decreases in size, allowing for timely treatment adjustments and avoidance of unnecessary toxicity.
Rare bladder neoplasms
In addition to typical urothelial carcinoma, other histological types require special attention:
- Squamous cell carcinoma: Composed entirely of squamous elements. Associated with chronic irritation and infections, characterized by high-grade malignancy and heterogeneous appearance on imaging.
- Urachal carcinoma: Arises from urachal remnants at the dome of the bladder. A pathognomonic symptom is mucus in the urine. CT frequently demonstrates specific punctate calcifications.
- Carcinoma in diverticula: Develops in the setting of urinary stasis. The prognosis for this form is worse due to rapid spread beyond the thinned diverticular wall.
Briefly: answers to topical questions
What imaging findings help differentiate a benign anastomotic stricture from local recurrence after cystectomy?
No reliable specific imaging features are specified to differentiate a benign anastomotic stricture from a recurrent or metachronous tumor. After radical cystectomy, anastomotic stricture—typically ureteroileal—is a common complication. Benign strictures of distal anastomoses are extremely difficult to distinguish from recurrent or metachronous tumors, although benign strictures are more common.
What are the histological types of bladder cancer?
The following histological types are described for bladder cancer in the sources:
- Urothelial carcinoma is the most frequent type of primary bladder tumors.
- Squamous cell carcinoma is diagnosed only if the tumor consists entirely of squamous elements.
- Adenocarcinoma is diagnosed only if the tumor consists entirely of adenomatous cells.
- Urachal carcinoma most commonly presents as adenocarcinoma, but transitional cell carcinoma, squamous cell carcinoma, and urachal sarcomas may also occur.
To which regional lymph nodes does bladder cancer metastasize?
According to the TNM classification, regional lymph nodes for bladder cancer include:
- pelvic lymph nodes: involvement of a single node corresponds to N1, more than one involved node corresponds to N2;
- common iliac lymph nodes: involvement of these or more central nodes corresponds to N3.
Class and exam questions
Why is it difficult to interpret imaging scans after transurethral resection?
Following surgery and BCG therapy, the bladder wall becomes thickened and scarred, which closely mimics tumor recurrence.
How is tumor response to chemotherapy assessed?
RECIST 1.1 criteria are primarily used by measuring changes in lesion dimensions on CT or MRI, alongside assessing metabolic activity on PET.
Which imaging modality is most accurate for detecting recurrences after TURBT?
Diffusion-weighted MRI (DWI) has the highest sensitivity and specificity in this scenario.
Where is urachal carcinoma most commonly localized?
The tumor is typically located in the midline on the anterosuperior surface of the bladder dome.
What else to study on this topic
- Imaging features of the reaction to BCG therapy
- CT urography protocols in upper urinary tract surveillance
- Differential diagnosis of anastomotic strictures and local recurrence
- Mechanism of squamous cell carcinoma development in chronic infections
- Evaluation of tumor functional parameters on dynamic contrast-enhanced MRI
Master the entire topic in the "Diagnostic Radiology" course
This is a summary. The course covers everything tested in classes and exams.
- Complete WhiteCoat Pro guide on "Monitoring treatment for bladder cancer" and 2,199 more pages on the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 10 video lessons on the subject
Other topics in the section "Diagnostic Radiology of the Abdominal Organs"
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.