A Prospective Study of a Resorbable Intravesical Fiducial Marker for Bladder Cancer Radiation Therapy

Purpose

We conducted a prospective pilot study to evaluate safety and feasibility of TraceIT, a resorbable radiopaque hydrogel, to improve image guidance for bladder cancer radiation therapy (RT).

Methods and Materials

Patients with muscle invasive bladder cancer receiving definitive RT were eligible. TraceIT was injected intravesically around the tumor bed during maximal transurethral resection of bladder tumor. The primary endpoint was the difference between radiation treatment planning margin on daily cone beam computed tomography based on alignment to TraceIT versus standard-of-care pelvic bone anatomy. The Van Herk margin formula was used to determine the optimal planning target volume margin. TraceIT visibility, recurrence rates, and survival were estimated by Kaplan-Meier method. Toxicity was measured by Common Terminology Criteria for Adverse Events version 4.03.

Results

The trial was fully accrued and 15 patients were analyzed. TraceIT was injected in 4 sites/patient (range, 4-6). Overall, 94% (95% confidence interval [CI], 90%-98%) of injection sites were radiographically visible at RT initiation versus 71% (95% CI, 62%-81%) at RT completion. The median duration of radiographic visibility for injection sites was 106 days (95% CI, 104-113). Most patients were treated with a standard split-course approach with initial pelvic radiation fields, then midcourse repeat transurethral resection of bladder tumor followed by bladder tumor bed boost fields, and 14/15 received concurrent chemotherapy. Alignment to fiducials could allow for reduced planning target volume margins (0.67 vs 1.56 cm) for the initial phase of RT, but not for the boost (1.01 vs 0.96 cm). This allowed for improved target coverage (D_95% 80%-83% to 91%-94%) for 2 patients retrospectively planned with both volumetric-modulated arc therapy and 3-dimensional conformal RT. At median follow-up of 22 months, no acute or late complications attributable to TraceIT placement occurred. No patients required salvage cystectomy.

Conclusions

TraceIT intravesical fiducial placement is safe and feasible and may facilitate tumor bed delineation and targeting in patients undergoing RT for localized muscle invasive bladder cancer. Improved image guided treatment may facilitate strategies to improve local control and minimize toxicity.

Prospective evaluation of a comprehensive geriatric assessment (CGA) in multidisciplinary bladder cancer care: Feasibility and impact on decisional conflict

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Background: Commonly utilized risk stratification tools demonstrate inconsistent associations with salient clinical outcomes in bladder cancer leading to a disproportionate reliance on providers’ subjective impression of a patient’s fitness for therapy. Current guidelines advocate for use of a CGA to quantify vulnerabilities in older ( > 65 years) patients before treatment selection. Our objective was to prospectively evaluate CGA in our Bladder Cancer Multidisciplinary Clinic (BCMC). We hypothesized that CGA implementation would be feasible and that discussion of the results during shared decision-making would be associated with reduced patient-reported decisional conflict. Methods: Patients seen in BCMC were prospectively enrolled from 6/1/20 to 7/20/21. In the first 3 months, participants underwent non-standardized risk stratification (“Routine cohort”, N = 27). Between 9/1/20 and 7/20/21, participants completed a CGA incorporating validated assessments of frailty, functional status, multimorbidity, nutrition, cognition, and mental health (“CGA cohort”, N = 67). Results were shared with patients during BCMC visits. All patients and providers (three physicians per clinic from: Uro-Oncology, Medical Oncology, and Radiation Oncology) completed a follow-up survey including the Decisional Conflict Scale (DCS). Time required to complete the CGA, completion rates, and patient-reported burden were assessed. Concordance of patient- and provider-reported decisional conflict was compared between Routine and CGA cohorts. Results: Of 138 eligible patients, 94 patients were successfully enrolled (68%) with median age of 72 years, ECOG PS ≥3 in 13%, and Charlson Comorbidity Index ≥3 in 18%, of whom 18% were women. Most patients had pT2 bladder cancer (87%; cN+ and M1 in 23.4% and 9.6%, respectively). CGA component completion rates were 79-100%. Survey response rates were high (patients: 77%, providers: 86%), and most (86%) patients felt that the CGA was, at most, minimally burdensome. Vulnerabilities detected across CGA domains triggered relevant referrals. Patient-reported median (IQR) DCS scores were numerically higher (e.g. greater decisional conflict) for the CGA cohort: (27 [14-33] vs 16 [2-30] for Routine patients, p = 0.28). Provider- and provider reported DCS score was correlated in the CGA (p = 0.04), but not the Routine cohort (p = 0.07). Conclusions: We prospectively evaluated use of CGAs in bladder cancer care and found that CGAs were successfully implemented with high rates of completion and low rates of perceived burden. Notably, in this pilot cohort of 94 patients, DCS scores did not differ significantly between patients and providers with CGA use. Future work will evaluate associations between individual instruments, treatment decisions, clinical outcomes and patient-reported quality of life measures.