Adjuvant radiotherapy after radical cystectomy for muscle-invasive bladder cancer: A retrospective multicenter study

Adjuvant Radiotherapy in Bladder Cancers: A Dosimetric Study Focusing on Ileal Conduit Sparing

PURPOSE

To compare ileal conduit (IC) and other organ at risk (OAR) dosimetry between treatment techniques in a prospective cohort of patients planned for adjuvant radiotherapy (RT) after radical cystectomy and IC reconstruction.

METHODS AND MATERIALS

Computed tomography (CT datasets of twenty patients who underwent adjuvant RT were obtained and used prospectively for delineation of target volumes (primary and nodal) and OARs, including IC, uretero-ileal anastomosis and ileal stoma using a specified protocol for simulation including a delayed CT to identify IC. Three RT plans were generated for each patient for a dose of 54 gray (Gy) in 27 fractions (PTV V95% >95%): 3-dimensional conformal radiotherapy (3DCRT) with (3DCRT_S) and without (3DCRT_N) stoma shielding, and volumetric modulated arc therapy (VMAT), with OAR constraints specified for VMAT plans (IC: Dmax<54Gy, V50Gy < 20 cc). Constraints were given for other pelvic OARs (bowel, rectum, femur heads) as per published literature. Plans were evaluated for target coverage as well as OAR doses; in particular, IC and ileal stoma). ANOVA test was used to compare medians of achieved doses, and a p-value <0.05 was statistically significant.

RESULTS

The median IC volume was 63.34 (55.29-82.93) cc. The cranial end of IC was at L5 or L4 vertebral level in 95% of patients and caudal level at S2 or S3 in 80% of patients. In contrast, the ileal stoma spanned from L4 or L5 vertebral level cranially (100%) to L5 level caudally (80%). PTV V95% was similar for 3DCRT_N and VMAT plans while it was significantly lower for 3DCRT_S in areas of ileal stoma shielding (99.95% vs 99.01% vs 96.29%, p < 0.01). Median IC V50Gy was comparable in 3DCRT_N (38.81 cc) and 3DCRT_S (35.62 cc) while it was significantly lower in the VMAT plan (17.05 cc, p < 0.01). IC Dmax did not differ significantly between the three plans. On the other hand, when 3DCRT_N, 3DCRT_S, and VMAT plans were compared for ileal stoma doses, Dmean was comparable (11.93 Gy vs 7.41 Gy vs 9.54 Gy, p = 0.06) while Dmax was significantly higher for 3DCRT_N plan and least for VMAT plan (35.32 Gy vs 27.57 Gy vs 24.22 Gy, p < 0.01). VMAT plans fared significantly better than both 3DCRT plans for uretero-ileal anastomosis, bowel, and rectal dosimetry.

CONCLUSIONS

Ileal stoma shielding in 3DCRT compromises PTV coverage but does not spare IC effectively. Sparing IC with VMAT is feasible without compromising PTV coverage. Dosimetric gains with VMAT are expected to benefit patients needing higher pelvic RT doses and nodal RT by reducing the risk of anastomotic and mucosal complications. Clinical benefits should be evaluated in a prospective protocol.

The Value and Safety of Adjuvant Radiation Therapy After Radical Cystectomy in Locally Advanced Urothelial Bladder Cancer: A Controlled Randomized Study

PURPOSE

Adjuvant radiation therapy (ART) after radical cystectomy in locally advanced bladder cancer was revived after the advancement in precise radiation therapy that decreased the normal pelvic tissue radiation hazards. However, there are still scarce controlled randomized studies addressing this issue.

METHODS AND MATERIALS

One hundred thirty-one cystectomized urothelial bladder cancer patients were enrolled; 122 were randomized to receive ART of 50 Gy/25 fractions 4 weeks after cystectomy or cystectomy alone (CY). Sixty-two were included in the ART arm and 60 in the CY arm. Twenty-four ART and 30 CY patients received neoadjuvant chemotherapy. Eleven patients (9%) had cotenant neobladder diversion, 6 in ART, and 5 in CY arms. All ART patients were treated with intensity modulated radiation therapy with daily verification cone beam computed tomography. The median follow-up was 42.7 months.

RESULTS

The 3-year adjusted locoregional recurrence-free survival rate was higher in the ART arm, measuring 81% (95% CI, 69%-94%) compared with 71% (95% CI, 60%-80%; p = .0457). ART significantly improved the locoregional relapse-free rate in the cystectomy bed and the pelvic side wall (p = .016 and p = .001, respectively). The overall, event-free, and distant metastasis-free survival did not rank to the level of statistical significance in the 2 arms. Even though the acute side effects were slightly higher in ART, the late toxicities were almost equal in the 2 groups.

CONCLUSIONS

ART is safe and quite tolerable after radical cystectomy when using precise radiation techniques. These techniques significantly improved the locoregional recurrence-free survival but had insignificant improvement on the overall survival. ART did not affect the distant metastasis-free survival. Similar studies are performed in different centers around the world to confirm the value of ART in urothelial bladder cancer.

Study Protocol of the Bladder Adjuvant RadioTherapy (BART) Trial: A Randomised Phase III Trial of Adjuvant Radiotherapy Following Cystectomy in Bladder Cancer

AIMS

To assess the efficacy and safety of adjuvant radiotherapy in patients with high-risk muscle-invasive bladder cancer (MIBC) following radical cystectomy (RC) and chemotherapy.

MATERIALS AND METHODS

The BART (Bladder Adjuvant RadioTherapy) trial is an ongoing multicentric, randomised, phase III trial comparing the efficacy and safety of adjuvant radiotherapy versus observation in patients with high-risk MIBC. The key eligibility criteria include ≥pT3, node-positive (pN+), positive margins and/or nodal yield <10, or, neoadjuvant chemotherapy for cT3/T4/N+ disease. In total, 153 patients will be accrued and randomised, in a 1:1 ratio, to either observation (standard arm) or adjuvant radiotherapy (test arm) following surgery and chemotherapy. Stratification parameters include nodal status (N+ versus N0) and chemotherapy (neoadjuvant chemotherapy versus adjuvant chemotherapy versus no chemotherapy). For patients in the test arm, adjuvant radiotherapy to cystectomy bed and pelvic nodes is planned with intensity-modulated radiotherapy to a dose of 50.4 Gy in 28 fractions using daily image guidance. All patients will follow-up with 3-monthly clinical review and urine cytology for 2 years and subsequently 6 monthly until 5 years, with contrast-enhanced computed tomography abdomen pelvis 6 monthly for 2 years and annually until 5 years. Physician-scored toxicity using Common Terminology Criteria for Adverse Events version 5.0 and patient-reported quality of life using the Functional Assessment of Cancer Therapy - Colorectal questionnaire is recorded pre-treatment and at follow-up.

ENDPOINTS AND STATISTICS

The primary endpoint is 2-year locoregional recurrence-free survival. The sample size calculation was based on the estimated improvement in 2-year locoregional recurrence-free survival from 70% in the standard arm to 85% in the test arm (hazard ratio 0.45) using 80% statistical power and a two-sided alpha error of 0.05. Secondary endpoints include disease-free survival, overall survival, acute and late toxicity, patterns of failure and quality of life.

CONCLUSION

The BART trial aims to evaluate whether contemporary radiotherapy after standard-of-care surgery and chemotherapy reduces pelvic recurrences safely and also potentially affects survival in high-risk MIBC.

Delineating and sparing the ileal conduit in adjuvant radiotherapy for bladder cancer with modulated radiotherapy

PURPOSE

We undertook a prospective planning study to describe the delineation of ileal conduit (IC) loop on radiotherapy planning computed tomography (RTP CT) scan as an organ at risk (OAR) and its sparing using volumetric modulated arc therapy (VMAT) during adjuvant irradiation of bladder malignancies.

MATERIALS AND METHODS

Fifteen patients with bladder malignancy needing adjuvant radiotherapy postoperatively and having normal renal function underwent delayed phase RTP CT from June 2020 to March 2021, with certain modifications (Foley's catheter through stoma, additional delayed scans). We identified the course of ureters, external stoma, IC, and uretero-ileal (right and left) anastomotic sites. VMAT plans were generated.

RESULTS

A step-by-step description is given. Genitourinary OARs include kidneys, ureters, uretero-ileal anastomoses, and IC. The contrast on delayed scan opacifies ureters and IC. IC can be seen three-dimensionally as a structure with two fixed ends (blind proximal end anterior to the right sacroiliac joint and the open distal end over the right anterior abdominal wall in parasagittal location) and a 15-20 cm hanging intraabdominal loop that lies adjacent to the right iliac vessels. For prescription doses (PD) of 50.4 gray and 54 gray, respectively, VMAT plan achieved IC dose maximum to less than PD and V50 lower than 10 cc. Stoma sparing traditionally used as a surrogate for IC sparing is insufficient due to the variable intraabdominal location of IC loop.

CONCLUSIONS

Delineation of IC as an OAR is feasible with slight modifications in the RTP protocols. VMAT (or other forms of intensity modulated radiation therapy) can help IC sparing and should be considered when it lies in close proximity to target volumes and the risk of additional morbidity is considerable.

[Pathological pelvic lymph node involvement in muscle-invasive bladder cancer patients treated with radical cystectomy: A narrative review]

OBJECTIVE

To perform a narrative review of the contemporary literature on the diagnosis, prognosis and adjuvant management of muscle-invasive bladder cancer (MIBC) patients with pathological pelvic lymph node involvement (pN+) at radical cystectomy.

METHOD

A narrative review of the contemporary literature available on Medline was conducted to report studies evaluating the diagnosis, prognosis and/or adjuvant treatments for MIBC patients with pN+ disease at radical cystectomy.

RESULTS

Open or robotic extended pelvic lymph node dissection up to the crossing of the ureter with common iliac vessels can enhance the diagnosis of pN+ MIBC, especially using separate packages for the submission of a maximum number of lymph nodes. The main prognosis factors for pN+ patients are the number of positive and retrieved lymph nodes, lymph node density, extranodal extension as well as lymph node metastasis diameter. Adjuvant chemotherapy is likely to prolong overall survival in pN+ patients treated with radical cystectomy alone while adjuvant immunotherapy using nivolumab has been shown to decrease the risk of recurrence in all pN+ patients, especially those with ypN+ disease after neoadjuvant chemotherapy followed by radical cystectomy. However, few data are currently available on the role of adjuvant radiation therapy, which remains currently experimental for these patients.

CONCLUSION

Multiple parameters have been reported to impact the diagnosis and prognosis of patients with pN+ MIBC at radical cystectomy. Adjuvant management is currently based on chemotherapy and immunotherapy with preliminary data on radiation therapy.

Perioperative therapy in muscle invasive bladder cancer

Radical cystectomy with bilateral pelvic lymph node dissection is the standard of care for muscle invasive bladder cancer (MIBC). The role of neoadjuvant and adjuvant therapy has evolved over the last 3–4 decades, and neoadjuvant chemotherapy (NACT) has now become the standard recommended treatment. However, there are many nuances to this and the utilization of chemotherapy has not been universal. The optimum chemotherapy regimen is still debated. Adjuvant radiation has a role in high-risk patients although not established and immunotherapy has shown promising results. We reviewed the evidence on NACT and adjuvant chemotherapy (ACT) regimens, NACT versus ACT, and the role of adjuvant radiotherapy and immunotherapy in MIBC.

Neobladder and ablative pelvic radiotherapy: still a taboo?

The presence of a neobladder constitutes a limitation for the radiation oncologist, as there is no clear evidence about its tolerance to radiotherapy (RT). The limited literature only concerns the conventional postoperative treatment in patients with bladder cancer after cystectomy. Here we report a case of a patient with neobladder who underwent a stereotactic RT for a pelvic recurrence of disease, with response to treatment and no toxicity to the neobladder. This case represents a promising example of the chance to perform RT with ablative intent, using advanced techniques, even on lesions close to the neobladder.

Bone Marrow Suppression during Postoperative Radiation for Bladder Cancer and Comparative Benefit of Proton Therapy—Phase 2 Trial Secondary Analysis

Purpose

For patients with high-risk bladder cancer (pT3⁺ or N⁺), local regional failure remains a challenge after chemotherapy and cystectomy. An ongoing prospective phase 2 trial (NCT01954173) is examining the role of postoperative photon radiation therapy for high-risk patients using volumetric modulated arc therapy. Proton beam therapy (PBT) may be beneficial in this setting to reduce hematologic toxicity. We evaluated for dosimetric relationships with pelvic bone marrow (PBM) and changes in hematologic counts before and after pelvic radiation therapy and explored the potential of PBT treatment plans to achieve reductions in PBM dose.

Materials and Methods

All enrolled patients were retrospectively analyzed after pelvic radiation per protocol with 50.4 to 55.8 Gy in 28 to 31 fractions. Comparative PBT plans were generated using pencil-beam scanning and a 3-beam multifield optimization technique. Changes in hematologic nadirs were assessed using paired t test. Correlation of mean nadirs and relative PBM dose levels were assessed using the Pearson correlation coefficient (CC).

Results

Eighteen patients with a median age of 70 were analyzed. Mean cell count values after radiation therapy decreased compared with preradiation therapy values for white blood cells (WBCs), absolute neutrophil count (ANC), absolute lymphocyte count (all P < .001), and platelets (P = .03). Increased mean PBM dose was associated with lower nadirs in WBC (Pearson CC −0.593, P = .02), ANC (Pearson CC −0.597, P = .02), and hemoglobin (Pearson CC −0.506, P = .046), whereas the PBM V30 to V40 correlated with lower WBC (Pearson CC −0.512 to −0.618, P < .05), and V20 to V30 correlated with lower ANC (Pearson CC −0.569 to −0.598, P < .04). Comparative proton therapy plans decreased the mean PBM dose from 26.5 Gy to 16.1 Gy (P < .001) and had significant reductions in the volume of PBM receiving doses from 5 to 40 Gy (P < .001).

Conclusion

Increased PBM mean dose and V20 to V40 were associated with lower hematologic nadirs. PBT plans reduced PBM dose and may be a valuable strategy to reduce the risk of hematologic toxicity in these patients.

Patterns of Locoregional Recurrence after Radical Cystectomy for Stage T3-4 Bladder Cancer: A Radiation Oncologist's Point of View

PURPOSE

Adjuvant radiotherapy (RT) has been performed to reduce locoregional failure (LRF) following radical cystectomy for locally advanced bladder cancer; however, its efficacy has not been well established. We analyzed the locoregional recurrence patterns of post-radical cystectomy to identify patients who could benefit from adjuvant RT and determine the optimal target volume.

MATERIALS AND METHODS

We retrospectively reviewed 160 patients with stage ≥ pT3 bladder cancer who were treated with radical cystectomy between January 2006 and December 2015. The impact of pathologic findings, including the stage, lympho-vascular invasion, perineural invasion, margin status, nodal involvement, and the number of nodes removed on failure patterns, was assessed.

RESULTS

Median follow-up period was 27.7 months. LRF was observed in 55 patients (34.3%), 12 of whom presented with synchronous local and regional failures as the first failure. The most common failure pattern was distant metastasis (40%). Among LRFs, the most common recurrence site was the cystectomy bed (15.6%). Patients with positive resection margins had a significantly higher recurrence rate compared to those without (28% vs. 10%, p=0.004). The pelvic nodal recurrence rate was < 5% in pN0 patients; the rate of recurrence in the external and common iliac nodes was 12.5% in pN+ patients. The rate of recurrence in the common iliac nodes was significantly higher in pN2-3 patients than in pN0-1 patients (15.2% vs. 4.4%, p=0.04).

CONCLUSION

Pelvic RT could be beneficial especially for those with positive resection margins or nodal involvement after radical cystectomy. Radiation fields should be optimized based on the patient-specific risk factors.

Adjuvant and Neoadjuvant Radiation Therapy for Locally Advanced Bladder Cancer

Local-regional failure for patients with ≥pT3 urothelial carcinoma after radical cystectomy is a significant clinical challenge. Prospective randomised trials have failed to show that chemotherapy reduces the risk of local-regional recurrences. Salvage treatment for local failures is difficult and often unsuccessful. There is promising evidence, particularly from a recent Egyptian National Cancer Institute trial, that radiation therapy plus chemotherapy can significantly reduce local recurrences compared with chemotherapy alone, and that this improvement in local-regional control may translate to meaningful improvements in disease-free and overall survival with acceptable toxicity. In light of the high rates of local failure following cystectomy for locally advanced disease and the progress that has been made in identifying patients at high risk of failure and the patterns of failure in the pelvis, the National Comprehensive Cancer Network guidelines were revised to include postoperative radiotherapy as an option to consider for patients with ≥pT3 disease. Here we review the problem of local-regional failure after cystectomy, identify patients who would probably benefit from adjuvant radiotherapy, review the patterns of pelvic failure after cystectomy, discuss technical details of radiation treatment and review the modern literature on this topic. Adjuvant radiotherapy should be considered as a treatment option for patients with locally advanced disease, especially those with positive margins or squamous cell carcinoma.

[Adjuvant radiotherapy after radical cystectomy for muscle-invasive bladder cancer]

OBJECTIVES

Locoregional relapse (LRR) after cystectomy is a common early event associated with poor prognosis. The role of radiotherapy as an adjunct to radical cystectomy is not well-defined. The aim of this critical literature review is to provide an overview of the elements in favor of adjuvant radiation for patients treated for muscle-invasive bladder cancer.

MATERIAL AND METHODS

An exhaustive review of the literature was carried out using the Pubmed search tool with the following keywords: "radiotherapy" [Mesh], "adjuvant" [Mesh], "local recurrence" [Mesh], "Bladder cancer" [Mesh].

RESULTS

Several recent publications have led to the development of a nomogram that predicts the risk of LRR, in order to identify patients for which adjuvant radiotherapy could be beneficial. Several randomized trials seem to suggest a benefit of radiotherapy, in particular when combined with chemotherapy, in terms of reducing LRR, and may even improve overall survival, with good safety profile. However, there are many biases and the interest of adjuvant radiotherapy in urothelial carcinomas remains debated.

CONCLUSION

Prospective trials evaluating adjuvant radiotherapy with current techniques should be undertaken.

Supplementary granulocyte macrophage colony-stimulating factor to chemotherapy and programmed death-ligand 1 blockade decreases local recurrence after surgery in bladder cancer

Despite advances and refinements in surgery and perioperative chemotherapy, there are still unmet medical needs with respect to radical cystectomy for muscle‐invasive bladder cancer (MIBC). We investigated the potential benefit of supplementary granulocyte macrophage colony‐stimulating factor (GM‐CSF) to chemoimmunotherapy with programmed cell death protein‐1 (PD‐1)/programmed death‐ligand 1 (PD‐L1) axis blockade and standard neoadjuvant chemotherapy in bladder cancer. We inoculated 2 × 10⁵MBT2 cells s.c. in C3H mice to create a syngeneic animal model of local recurrence (LR). When the tumor diameter reached 12 mm, the mice were allocated randomly as follows: (i) non‐treated control (vehicle only); (ii) anti‐mPD‐L1 monotherapy; (iii) mGM‐CSF monotherapy; (iv) anti‐mPD‐L1 plus mGM‐CSF; (v) gemcitabine and cisplatin (GC); (vi) GC plus anti‐mPD‐L1; (vii) GC plus mGM‐CSF; and (viii) GC plus anti‐mPD‐L1 plus mGM‐CSF. After completing 2‐week neoadjuvant therapy, tumors were resected for resection margin evaluation and immunohistochemical staining and blood was collected for flow cytometry and ELISA. Operative wounds were sutured, and the operative site was monitored to detect LR. Addition of anti‐mPD‐L1 and mGM‐CSF to neoadjuvant GC chemotherapy enhanced the antitumor effect and reduced positive resection margins (50% vs 12.5%). Combination of GC, anti‐mPD‐L1, and mGM‐CSF resulted in longer LR‐free survival and cancer‐specific survival compared to those in other groups. These effects involved an immunotherapy‐related decrease in oncological properties such as tumor invasion capacity and epithelial‐mesenchymal transition. mGM‐CSF significantly decreased the accumulation of myeloid‐derived suppressor cells in both the blood and tumor microenvironment and blood interleukin‐6 levels. Supplementary GM‐CSF to neoadjuvant GC plus PD‐L1 blockade could decrease LR after radical surgery by immune modulation in the blood and tumor microenvironment.

Bladder cancer mortality after a diagnosis of nonmuscle-invasive bladder carcinoma

Aim: To assess mortality from bladder cancer following a diagnosis of nonmuscle-invasive bladder cancer. Materials & methods: This is a SEER registry-based study. The risk of death from bladder cancer was compared with that of the general population. Cox proportional model was performed to calculate the hazard ratio (HR) for death according to baseline characteristics. Results: The bladder cancer-specific mortality at 20 years was 11%; and it was higher for black patients compared with white patients (adjusted HR: 1.711 [95% CI: 1.564-1.872]; p  <  0.0001); additionally, it was higher for patients older than 70 years old compared with younger patients (adjusted HR: 2.005 [95% CI: 1.916-2.099]; p  < 0 .0001). The risk of bladder cancer mortality increased after diagnosis of a recurrent bladder cancer (both nonmuscle-invasive and muscle-invasive; adjusted HR: 6.97 [95% CI: 6.56-7.40]; p  < 0 .0001). Conclusion: Important predictors for death from bladder cancer following a diagnosis of nonmuscle-invasive bladder cancer include older age at diagnosis and black race.

National Practice Patterns and Overall Survival After Adjuvant Radiotherapy Following Radical Cystectomy for Urothelial Bladder Cancer in the USA, 2004-2013

BACKGROUND

Adjuvant radiation therapy (ART) after radical cystectomy (RC) for urothelial bladder cancer (UBC) may play a role in the management of muscle-invasive BC, particularly in patients with locally advanced disease and adverse pathologic features (pT3/4 or positive surgical margins [PSMs]). Evidence regarding the effect of ART on overall survival (OS) is lacking.

OBJECTIVE

To evaluate national practice patterns for the use of ART and assess its impact on OS for patients with adverse pathologic features (APF) after RC.

DESIGN, SETTING, AND PARTICIPANTS

Using the National Cancer Data Base, we analyzed all UBC cases with APF after RC from 2004 to 2013. Patients were divided into ART and no-ART groups.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Relationships with oncological outcomes were analyzed using multivariable Cox regression and log-rank analyses.

RESULTS AND LIMITATIONS

Use of ART decreased during the study period from 3.1% in 2004 to 1.7% in 2013 (p=0.03). ART was administered in 1.4%, 4.0% and 5.2% of patients with pT3 UBC, pT4 UBC, and PSMs (any pT stage), respectively. The rate of ART was significantly higher among younger ages, female sex, low-volume hospitals, nonacademic community care centers, higher stages, PSMs, perioperative chemotherapy, and lymph node-positive disease. Predictors of ART receipt were PSMs (odds ratio [OR] 3.4; p<0.0001), pT4 (OR 2.6; p=0.02), community based centers (OR 2.1; p<0.0001), and female sex (OR 1.8; p<0.0001). Risk factors for worse OS included age, higher tumor stage and comorbidities, PSMs, positive nodes, and suboptimal lymph node dissection (<10 nodes removed; all p<0.001). ART was not independently associated with better OS in the full cohort (p=0.54). However, subgroup analyses suggested an OS benefit for patients with PSMs (hazard ratio 0.73; p=0.047). Limitations include the retrospective design and limited details regarding cancer-specific survival.

CONCLUSIONS

Use of ART for APF following RC is not common in the USA and the rate of ART has been decreasing over time. ART may have an OS benefit after RC for patients with PSMs.

PATIENT SUMMARY

In this report we looked at the outcomes for patients with locally advanced bladder cancer receiving adjuvant radiation therapy following cystectomy in a large US population. We found that adding radiation therapy after removing the bladder cancer may have some survival benefits for patients with positive surgical margins.

Development of a Prediction Tool for Exclusive Locoregional Recurrence After Radical Cystectomy in Patients With Muscle-Invasive Bladder Cancer

BACKGROUND

Limited information is available about the pattern of relapse after perioperative chemotherapy with radical cystectomy (RC) vs. RC alone in muscle-invasive bladder cancer.

PATIENTS AND METHODS

Data from 1082 patients of the Retrospective International Study of Invasive/Advanced Cancer of the Urothelium database, treated from February 1990 to December 2013 at 27 centers in the United States, Europe, Israel, and Canada, were collected. Locoregional relapse was defined as any pelvic lymph node or soft tissue-only recurrences. Cumulative incidence methods were used to estimate time to locoregional relapse (TTR_L). Cox regression analyses were performed and a nomogram for 12-month locoregional relapse-free survival (RFS) was developed. The nomogram was applied to an external data set (n = 1021).

RESULTS

A total of 517 patients (47.8%) developed a relapse: 177 (16.4%) exclusive locoregional relapse. In multivariable analyses, perioperative chemotherapy was associated with longer TTR_L (P < .001). Other factors were nonurothelial histology (P = .013), pT-stage (P < .001), and surgical margins (P < .001). The concordance index of the model was 0.681 (95% bootstrapped confidence interval, 0.666-0.716). Risk group categories were obtained according to nomogram tertiles. Despite, overall, observed locoregional RFS in the validation cohort exceeding predicted results, for high-risk patients (80 points or less, lowest nomogram tertile) observed 12-month RFS was similar between development and validation cohorts (60.1% and 66.6%). The study is limited by its retrospective nature.

CONCLUSION

In the largest study, to our knowledge, that analyzed locoregional recurrences after RC, we propose a risk prediction tool for exclusive locoregional failures that might be suitable for clinical studies. Patients best suited for adjuvant radiotherapy might be those within the lowest nomogram tertile. Prospective trials are needed to validate findings.

The Role of Adjuvant Radiation Therapy in Locally Advanced Bladder Cancer

Background:

The standard of care for locally advanced bladder cancer (LABC) is neoadjuvant chemotherapy followed by cystectomy. However, the role of adjuvant therapy for locally advanced bladder cancer is unclear.

Objective:

The purpose of this study was to evaluate the outcomes of adjuvant radiation therapy (RT) for patients with LABC, and to determine which risk factors best predict for patients who may best benefit from adjuvant RT.

Methods:

The National Cancer Data Base (NCDB) was queried (2004– 2013) for patients with newly-diagnosed pT3-4N0-3M0 urothelial carcinoma of the bladder that received neoadjuvant chemotherapy and cystectomy. Patients were divided into two groups based on the adjuvant therapy they received: RT or observation. Statistics included multivariable logistic regression to determine factors predictive of receiving adjuvant RT, Kaplan-Meier analysis to evaluate overall survival (OS), and Cox proportional hazards modeling to determine variables associated with OS.

Results:

Altogether, 1,646 patients met inclusion criteria; 59 (3.6%) patients received adjuvant RT, while 1,587 (96.4%) were observed. Patients treated with adjuvant RT were more likely to be female, have positive surgical margins, and receive treatment at a non-academic facility. There was no difference in median overall survival (OS) between patients treated with RT when compared to patients observed (17.7 months vs. 23.5 months; p = 0.085). However, an improvement in median OS with the use of adjuvant RT was observed among patients with positive surgical margins (20.3 months vs. 13.1 months; p = 0.032). On multivariate analysis, advancing age, pT4 stage, positive N stage, positive margins, and lower socioeconomic status were associated with worse OS.

Conclusions:

In the largest study to date evaluating efficacy of adjuvant radiotherapy in patients with locally advanced bladder cancer, use of RT was not associated with OS in all patients, while RT was associated with improvemed OS among patients with positive surgical margins. Prospective studies are recommended to confirm these findings.