Clinical results of conformal versus intensity-modulated radiotherapy using a focal simultaneous boost for muscle-invasive bladder cancer in elderly or medically unfit patients

Minimizing human interference in an online fully automated daily adaptive radiotherapy workflow for bladder cancer

PURPOSE

The aim was to study the potential for an online fully automated daily adaptive radiotherapy (RT) workflow for bladder cancer, employing a focal boost and fiducial markers. The study focused on comparing the geometric and dosimetric aspects between the simulated automated online adaptive RT (oART) workflow and the clinically performed workflow.

METHODS

Seventeen patients with muscle-invasive bladder cancer were treated with daily Cone Beam CT (CBCT)-guided oART. The bladder and pelvic lymph nodes (CTVelective) received a total dose of 40 Gy in 20 fractions and the tumor bed received an additional simultaneously integrated boost (SIB) of 15 Gy (CTVboost). During the online sessions a CBCT was acquired and used as input for the AI-network to automatically delineate the bladder and rectum, i.e. influencers. These influencers were employed to guide the algorithm utilized in the delineation process of the target. Manual adjustments to the generated contours are common during this clinical workflow prior to plan reoptimization and RT delivery. To study the potential for an online fully automated workflow, the oART workflow was repeated in a simulation environment without manual adjustments. A comparison was made between the clinical and automatic contours and between the treatment plans optimized on these clinical (Dclin) and automatic contours (Dauto).

RESULTS

The bladder and rectum delineated by the AI-network differed from the clinical contours with a median Dice Similarity Coefficient of 0.99 and 0.92, a Mean Distance to Agreement of 1.9 mm and 1.3 mm and a relative volume of 100% and 95%, respectively. For the CTVboost these differences were larger, namely 0.71, 7 mm and 78%. For the CTVboost the median target coverage was 0.42% lower for Dauto compared to Dclin. For CTVelective this difference was 0.03%. The target coverage of Dauto met the clinical requirement of the CTV-coverage in 65% of the sessions for CTVboost and 95% of the sessions for the CTVelective.

CONCLUSIONS

While an online fully automated daily adaptive RT workflow shows promise for bladder treatment, its complexity becomes apparent when incorporating a focal boost, necessitating manual checks to prevent potential underdosage of the target.

Cone-Beam Computed Tomography-Guided Online Adaptive Radiotherapy: Promising Results for Bladder Cancer Case

Bladder radiotherapy is challenging due to daily anatomical variations and unpredictable bladder filling, particularly affecting tumors in the cranial part. Conventional radiotherapy requires large planning target volume margins to manage these uncertainties, but this can expose healthy tissue to high radiation doses, increasing the risk of acute and late toxicity. Our aim was to study the potential to limit high-dose exposure to healthy tissue by comparing daily online adaptive radiotherapy (oART) with conventional, non-adaptive radiotherapy (non-ART). The comparison was performed on a bladder cancer patient treated with a simultaneous integrated boost while having a challenging tumor location in the cranial part of the bladder. Liquid fiducial markers aided during the localization of the tumor bed to deliver this focal boost. The dose distribution of oART fractions performed in the clinic was compared with simulated non-ART fractions on the post-treatment cone-beam computed tomography (CBCT). The results showed that while maintaining target coverage of the bladder and gross tumor volume in 100% of the fractions for both workflows, the high dose exposure to organs-at-risk was lower for oART. The small bowel received statistically significantly (p ≤ 0.05) less dose with oART compared to non-ART, with a median volume difference of 20 cm3 receiving 95% of the prescribed dose (55 Gy). The total volume of tissue outside the target receiving 95% of the prescribed dose was also smaller for oART compared to non-ART (p ≤ 0.05). The follow-up of two years showed that the patient had no long-term toxicity effects. Therefore, CBCT-guided oART has been shown to offer a conformal treatment for a challenging patient and can provide a clear advantage in the treatment of bladder cancer.

The role of radiation therapy for de novo metastatic bladder and renal cancers

Metastatic bladder and renal cancers account respectively for 2.1% and 1.8% of cancer deaths worldwide. The advent of immune checkpoint inhibitors has revolutionized the management of metastatic disease, by demonstrating considerable improvements in overall survival. However, despite initial sensitivity to immune checkpoint inhibitors for most patients, both bladder and renal cancer are associated with short progression-free survival and overall survival, raising the need for further strategies to improve their efficacy. Combining systemic therapies with local approaches is a longstanding concept in urological oncology, in clinical settings including both oligometastatic and polymetastatic disease. Radiation therapy has been increasingly studied with either cytoreductive, consolidative, ablative or immune boosting purposes, but the long-term impact of this strategy remains unclear. This review intends to address the impact of radiation therapy with either curative or palliative intent, for synchronous de novo metastatic bladder and renal cancers.

Online adaptive radiotherapy for bladder cancer using a simultaneous integrated boost and fiducial markers

PURPOSE

The aim was to assess the feasibility of online adaptive radiotherapy (oART) for bladder cancer using a focal boost by focusing on the quality of the online treatment plan and automatic target delineation, duration of the workflow and performance in the presence of fiducial markers for tumor bed localization.

METHODS

Fifteen patients with muscle invasive bladder cancer received daily oART with Cone Beam CT (CBCT), artificial intelligence (AI)-assisted automatic delineation of the daily anatomy and online plan reoptimization. The bladder and pelvic lymph nodes received a total dose of 40 Gy in 20 fractions, the tumor received an additional simultaneously integrated boost (SIB) of 15 Gy. The dose distribution of the reference plan was calculated for the daily anatomy, i.e. the scheduled plan. Simultaneously, a reoptimization of the plan was performed i.e. the adaptive plan. The target coverage and V95% outside the target were evaluated for both plans. The need for manual adjustments of the GTV delineation, the duration of the workflow and the influence of fiducial markers were assessed.

RESULTS

All 300 adaptive plans met the requirement of the CTV-coverage V95%≥98% for both the boost (55 Gy) and elective volume (40 Gy). For the scheduled plans the CTV-coverage was 53.5% and 98.5%, respectively. Significantly less tissue outside the targets received 55 Gy in case of the adaptive plans as compared to the scheduled plans. Manual corrections of the GTV were performed in 67% of the sessions. In 96% of these corrections the GTV was enlarged and resulted in a median improvement of 1% for the target coverage. The median on-couch time was 22 min. A third of the session time consisted of reoptimization of the treatment plan. Fiducial markers were visible on the CBCTs and aided the tumor localization.

CONCLUSIONS

AI-driven CBCT-guided oART aided by fiducial markers is feasible for bladder cancer radiotherapy treatment including a SIB. The quality of the adaptive plans met the clinical requirements and fiducial markers were visible enabling consistent daily tumor localization. Improved automatic delineation to lower the need for manual corrections and faster reoptimization would result in shorter session time.

Systemic therapy issues: Immunotherapy in nonmetastatic urothelial cancer

Non-muscle-invasive bladder cancer is one of the most common malignancies. Patients with intermediate-risk or high-risk disease can be treated with intravesical Bacillus Calmette-Guerin, a vaccine against tuberculosis. However, many of these patients will experience tumor recurrence, despite appropriate treatment. 1 The standard of care in these patients is radical cystectomy (RC) with urinary diversion. 2 Patients diagnosed with muscle-invasive bladder cancer (MIBC) have traditionally faced 2 main treatment options: RC and urinary diversion, as in Bacillus Calmette-Guerin-unresponsive Non-muscle-invasive bladder cancer, or alternatively, trimodal therapy comprising maximal transurethral resection of bladder tumor plus chemoradiation. 3 For patients with MIBC and clinical (c)T2-T4a, neoadjuvant chemotherapy (NAC) preceding RC is supported by Level 1 evidence with a modest 5-year overall survival benefit of 5% with cisplatin-based regimens. 4-9 A number of factors preclude MIBC patients from standard treatment options. For example, patients with serious comorbidities might be unable to tolerate general anesthesia, while others might be unwilling to adapt to the lifestyle changes after RC. 10-12 Likewise, patients with extensive carcinoma in situ or poor bladder function might not be optimal candidates for trimodal therapy or be prepared for the ongoing risk that salvage RC might be ultimately required. Reasons for the underuse of NAC range from the fear of delaying potentially curative surgery in nonresponders to patient ineligibility to cisplatin-based NAC. 13,14 Despite best efforts, in both surgical and bladder-sparing approaches, the 5-year overall survival in treated patients with MIBC is only 35% to 50%. 3,15 Strategies to improve overall prognosis as well as to reduce the indications of RC are desperately needed. Trial results have demonstrated the unprecedented ability of immune-checkpoint inhibitors to induce durable remissions in some patients with metastatic urothelial carcinoma. 16-20 Furthermore, immune-checkpoint inhibitors have shown to be better tolerated than traditional chemotherapy. 16 These successful results have spearheaded the research on these agents in earlier curative settings, with the shared goal of improving overall outcomes, and potentially avoid surgery in patients who show complete response (pT0). Strategies to enhance the immune response by combining immunotherapy with immune sensitizers such as chemotherapy, immunotherapy, targeted therapy or radiation are on the rise.

Bladder-sparing (chemo)radiotherapy in elderly patients with muscle-invasive bladder cancer: a retrospective cohort study

BACKGROUND

Organ-sparing treatment for muscle-invasive bladder cancer by maximal transurethral removal of the tumor (TURB) followed by chemoradiation (CRT) has shown promising results in recent studies, and is therefore considered to be an acceptable alternative for the standard of radical cystectomy (RC) in selected patients. We report on outcomes in a single-center, retrospective CRT cohort in comparison to a RC and radiotherapy only (RT) cohort.

PATIENTS AND METHODS

The patient population included n = 84 CRT patients, n = 93 RC patients, and n = 95 RT patients. Primary endpoints were local control (LC) up to 2 years and overall survival (OS) up to 5 years. Cox regression was performed to determine risk factors for LC and OS in the CRT group. Acute genito-urinary (GU) and gastro-intestinal (GI) toxicity were scored with CTCAE version 4 for the RT and CRT cohort. Logistic regression was used to determine risk factors for toxicity. We followed the EQUATOR guidelines for reporting, using the STROBE checklist for observational research.

RESULTS

Baseline characteristics were different between the treatment groups with in particular worse comorbidity scores and higher age in the RT cohort. The CRT schedule was completed by 96% of the patients. LC at 2 years was 83.4% (90% CI 76.0-90.8) for CRT vs. 70.9% (62.2-79.6) for RC and 67.0% (56.8-77.2) for RT. OS at 5 years was 48.9% (38.4-59.4) for CRT vs. 46.6% (36.4-56.8) for RC, and 27.6% (19.4-35.8) for RT. High T stage was significantly associated with worse LC and OS in the CRT group. GU/GI toxicity grade ≥2 occurred in 43 (48.3%) RT patients and 38 (45.2%) CRT patients.

CONCLUSIONS

The organ-preserving strategy with CRT was feasible and tolerable in this patient population, and the achieved LC and OS were satisfactory in comparison to the RC cohort and literature.

Role of radiotherapy in the management of bladder cancer: Recommendations of the French society for radiation oncology

We present the recommendations of the French society of oncological radiotherapy on the indications and techniques for external beam radiotherapy for bladder cancer.

Bladder-Sparing Chemoradiotherapy Combined with Immune Checkpoint Inhibition for Locally Advanced Urothelial Bladder Cancer-A Review

Simple Summary

Immunotherapy with immune checkpoint inhibition (ICI) has provided durable treatment responses in advanced, metastatic, bladder cancer patients. The first trials using checkpoint inhibitors before surgery, when the cancer is still confined to the pelvis, without signs of metastasis, have reported promising results. We reviewed the literature to identify clinical trials combining ICI with bladder-sparing chemoradiotherapy (CRT). Radiotherapy stimulates the immune system, thereby possibly inducing an additive effect in combination with checkpoint inhibition. Currently, twelve trials are treating patients with this immunochemoradiotherapy (iCRT) combination treatment. Several combinations with different chemotherapeutics and ICI added to CRT appear safe and feasible. Further research and comparative trials are needed to prove whether iCRT has additional clinical value for bladder cancer patients.

Abstract

Despite current treatment strategies, the 5-year overall survival of muscle-invasive bladder cancer (MIBC) is approximately 50%. Historically, radical cystectomy (RC) with neoadjuvant chemotherapy has been the first-choice treatment for this patient group. Recently, several studies have reported encouraging results of using immune checkpoint inhibitors (ICI) prior to RC. However, in recent years, bladder-sparing alternatives such as CRT have gained popularity. The effect of radiotherapy on the tumor microenvironment is an important rationale for combining CRT with ICI therapy. Worldwide, twelve immunochemoradiotherapy (iCRT) trials are ongoing. Each study employs a different chemotherapy and radiotherapy regimen and varies the timing of ICI administration concurrent to radiotherapy, adjuvant, or both. Five studies have presented (preliminary) results showing promising safety and short-term survival data. The first peer-reviewed publications are expected in the near future. The preclinical evidence and preliminary patient data demonstrate the potential of iCRT bladder-sparing treatment for bladder cancer.

Trends and Predictors of Hypofractionated and Intensity-Modulated Radiotherapy for Organ Preservation in Bladder Cancer

INTRODUCTION

Use of hypofractionated radiation (HFRT) and intensity-modulated radiation (IMRT) for organ preservation in bladder cancer is controversial and highly variable. We investigated practice patterns, trends, and predictors of HFRT and IMRT.

PATIENTS AND METHODS

The National Cancer Database was queried for patients with muscle-invasive, non-metastatic urothelial bladder cancer, treated with definitive (chemo)radiotherapy between 2004 and 2017. HFRT was defined as 50 to 60 Gy at >2 Gy/fraction. Multivariable logistic regression was used to identify predictors of receiving HFRT or IMRT. Multivariable Cox regression was used to model overall survival (OS), adjusting for potential confounders such as age, comorbidity, and chemotherapy.

RESULTS

Of 5132 patients identified, 490 (9.5%) received HFRT, and only 334 (6.5%) received ≥2.5 Gy/fraction. HFRT patients were significantly older, less fit, and less likely to receive chemotherapy relative to CFRT, even after controlling for age and comorbidity (adjusted odds ratio 0.36, 95% confidence interval [CI] 0.29-0.45, P < .0001). Utilization of HFRT and IMRT increased over time (P < .0001), reaching 22.5% and 47.7%, respectively, by 2017. Among patients treated with CFRT, OS was similar with or without IMRT (P = .46). Among patients treated with HFRT, IMRT was associated with increased survival (3-year OS 35% vs. 24%, P = .03), which persisted in multivariable analysis (adjusted hazard ratio 0.71, 95% CI 0.52-0.98, P = .04).

CONCLUSION

HFRT is largely underutilized, being primarily reserved for older, frailer patients. Chemotherapy is significantly underused with HFRT relative to CFRT. IMRT is used frequently and was associated with equivalent or modestly increased overall survival.

Recommendations for planning and delivery of radical radiotherapy for localized urothelial carcinoma of the bladder

PURPOSE

Curative radio-chemotherapy is recognized as a standard treatment option for muscle-invasive bladder cancer (MIBC). Nevertheless, the technical aspects for MIBC radiotherapy are heterogeneous with a lack of practical recommendations.

METHODS AND MATERIALS

In 2018, a workshop identified the need for two cooperative groups to develop consistent, evidence-based guidelines for irradiation technique in the delivery of curative radiotherapy. Two radiation oncologists performed a review of the literature addressing several topics relative to radical bladder radiotherapy: planning computed tomography acquisition, target volume delineation, radiation schedules (total dose and fractionation) and dose delivery (including radiotherapy techniques, image-guided radiotherapy (IGRT) and adaptive treatment modalities). Searches for original and review articles in the PubMed and Google Scholar databases were conducted from January 1990 until March 2020. During a meeting conducted in October 2020, results on 32 topics were presented and discussed with a working group involving 15 radiation oncologists, 3 urologists and one medical oncologist. We applied the American Urological Association guideline development's method to define a consensus strategy.

RESULTS

A consensus was obtained for all 34 except 4 items. The group did not obtain an agreement on CT enhancement added value for planning, PTV margins definition for empty bladder and full bladder protocols, and for pelvic lymph-nodes irradiation. High quality evidence was shown in 6 items; 8 items were considered as low quality of evidence.

CONCLUSION

The current recommendations propose a homogenized modality of treatment both for routine clinical practice and for future clinical trials, following the best evidence to date, analyzed with a robust methodology. The XXX group formulates practical guidelines for the implementation of innovative techniques such as adaptive radiotherapy.

The role of palliative radiotherapy in the management of elderly and frail patients with advanced bladder cancer: A survey by the AIRO uro-group

Radiotherapy (RT) is rarely used in the palliative management of muscle-invasive bladder cancer (MIBC). This survey aims to explore current care patterns within the Italian Radiation Oncologist community on this topic. In 2020, the uro-oncological study group of the Italian Association of Radiotherapy and Clinical Oncology (AIRO) conducted a survey evaluating the RT role in advanced MIBC. An electronic questionnaire was administered online to the society members asking for: general considerations, patients' selection, and aim of the treatment, RT schedule and practical consideration, past and future perspective. Sixty-one questionnaires were returned (33% response rate). Most responders (62.30%) declared to work in a Center with a multidisciplinary uro-oncological team, and 8.20% to evaluate more than 20 patients with MIBC/year for palliative RT. Elderly patients were the most frequently evaluated (46.7%) and life expectancy was the most common selection criteria (44.60%). Thirty Gy in 10 fractions (58.9%), whole bladder as GTV (62.5%), PTV isotropic margins of 1.5-2 cm (44.6%) and IMRT/VMAT technique (58.14%) were the most common treatment choices. Patients amenable for bladder palliative RT were most commonly referred by the urologist (43.86%) or the multidisciplinary team (38%). The reported main reasons for the low involvement of radiation oncologist in the management of MIBC patients were low attention to the palliative setting in bladder cancer (37.5%); radiation oncologist not involved in the management of these patients (32.1%); cases not discussed in the multidisciplinary board (26.8%). This survey illustrated the current use of palliative RT for patients with advanced MIBC in Italy and suggested the need for a greater involvement of radiation oncologists in their management.

The interaction of gender and smoking on bladder cancer risks

PURPOSE OF REVIEW

Although smoking and gender are well-established bladder cancer (BCa) risk factors, a significant interaction with other risk factors could help in the identification of patterns for early detection and prevention strategies.

RECENT FINDINGS

Smoking appears to be more strongly associated with BCa risk in women than in men, which could be related to differences in metabolism, smoking behavior, exposure patterns, and DNA repair mechanisms. BMI is associated with a higher risk of BCa with negligible difference between genders. The risk for BCa is increased in postmenopausal women, specifically in women with earlier menopausal age (<45 years). Other potential risk factors such as alcohol, arsenic exposure, and particulate matter inhalation seem to affect the genders differently.Female smokers experience a higher risk of disease recurrence after bacillus Calmette-Guérin therapy than their male counterparts. Lastly, smoking appears to negatively affect the outcome of radiotherapy in women, but not that of men.

SUMMARY

Several lines of evidence point to an interaction between smoking and gender, whereas their impact on other potential risk factors remains to be elucidated. Identifying such differential effects could allow for gender-specific prevention, early detection, and treatment strategies.

Management of Muscle-invasive Bladder Cancer in the 2020s: Challenges and Perspectives

Despite an increased use of neoadjuvant and adjuvant chemotherapy, the long-term survival rates after radical cystectomy or trimodal therapy (TMT) for muscle-invasive bladder cancer (MIBC) remain basically unchanged for decades. Detection and effective treatment of micrometastatic disease are still a clinical dilemma. Assessment of circulating tumor DNA in combination with improved imaging modalities may improve the prediction of micrometastatic disease. Different genetic subtypes of MIBC show varying degrees of chemosensitivity. Further progress needs to be made in order to develop a common molecular classifier that can be used easily for daily clinical decision making. With the advent on immuno-oncology, bladder-sparing protocols are on the rise as an alternative to surgery. The extent of transurethral bladder tumor resection has a marked impact on the response rates to TMT and neoadjuvant chemotherapy. This review focuses on strategies regarding how to integrate surgery, radiotherapy, and molecular-based systemic treatment for improved oncological outcomes of patients with MIBC. PATIENT SUMMARY: Effective treatment of micrometastatic disease is the key to improved oncological outcomes in muscle-invasive bladder cancer and requires a multidisciplinary approach.

Comparative effectiveness of radical cystectomy and radiotherapy without chemotherapy in frail patients with bladder cancer

Objectives: To evaluate cancer-specific (CSS) and overall survival (OS) in a group of frail patients who were treated with RT without chemotherapy and to compare them with a matched cohort of patients treated with RC.Methods: This study identified 71 patients treated with RT only for high-risk bladder cancer. Patients with metastatic (cN + or cM+) or non-resectable tumors (cT4) and those who received any form of chemotherapy were excluded. Patients where matched 1:1 using propensity scores which adjusted for the effects of age, clinical stage and age-adjusted Charlson comorbidity index (CCI). OS and CSS were evaluated using the Cox proportional hazards regression model and the Fine and Gray competing risk model.Results: In the overall population, RT was associated with worse OS (HR = 1.78, 95% CI = 1.15-2.77, p = 0.01) compared to RC, but not with CSS (HR 1.1, p = 0.74). In the matched cohort, RT was neither associated with OS nor CSS (p > 0.05) compared to RC. In the competing risk analyses no statistically significant association of any of the treatments was observed in the total or in the matched data set (p > 0.05).Conclusion: The use of RT may be an alternative option in well selected patients with limited disease who are considered unfit for systemic chemotherapy and RC. Future research should focus on improving patient selection and assess the quality-of-life as well as the need for reintervention in patients treated with RT.

Intensity-Modulated Radiotherapy is Superior to Three-Dimensional Conformal Radiotherapy in the Trimodality Management of Muscle-Invasive Bladder Cancer with Daily Cone Beam Computed Tomography Optimization

Objective

Intensity modulated radiation therapy (IMRT) using a volumetric-modulated arc therapy technique may offer dosimetric and clinical benefits compared to the historical standard of care 3D-conformal radiotherapy (3D-CRT) in definitive treatment of bladder cancer. We hypothesized that IMRT with CBCT would reduce dose to the rectum, bowel, and bladder compared to 3D-CRT.

Methods

We reviewed nineteen patients treated with maximal transurethral resection of bladder tumor followed by concurrent chemotherapy with IMRT. All patients received 45 Gy to the entire empty bladder followed by 19.8 Gy tumor boost treated with full bladder. 3D-CRT treatment plans were created for the same prescription. Paired t-test or Wilcoxon matched-pairs signed rank test analyzed dosimetry and bladder volumes.

Results

The rectum and bowel V40, V45, V50, V55, and V60 were reduced by over 50% in the IMRT plans compared to 3D-CRT (p<0.0001). IMRT also reduced volume of bladder irradiated compared to 3D-CRT (p<0.01). After CBCT, patients were likely to undergo clinically significant shifts ≥ 0.5 cm before boost delivery (p=0.001). Bladder volumes were significantly lower during boost treatments compared to pre-treatment simulation (p=0.002). There were 4 (21%) grade 3 genitourinary toxicities and 1 (5%) grade 3 gastrointestinal toxicity.

Conclusion

IMRT is superior to 3D-CRT for bladder cancer and spares dose to bowel, rectum, and bladder with improved acute toxicity compared to published clinical literature. For boost treatment, daily full bladder volume and positioning are not always reproducible, supporting the need for CBCT for optimal localization of the primary bladder tumor.

[Organ preservation by chemoradiation for bladder cancer]

When localized, the reference treatment of urothelial, muscle-invasive bladder tumours relies on radical cystectomy with reconstruction by enterocystoplasty if possible or Bricker bypass. Trimodal therapy combining transurethral resection of the tumour followed by concomitant chemotherapy may be considered as a therapeutic alternative to radical cystectomy in well-selected patients with unifocal tumours, stage T2, non-diverticular location, without in situ carcinoma or hydronephrosis and with macroscopically complete transurethral resection. The functional prognosis of the bladder and quality of life should be discussed with the patient as well as the need for salvage surgery for persistent tumour at a 45-Gy dose level, the latter being a highly unfavourable prognosis factor. On the other hand, this trimodal treatment is the reference in case of surgical contraindication. This article details the methods and results of the main series available in the literature in terms of local control, survival, bladder preservation rates and complications, as well as study prospects.

Linking surgical skills to postoperative outcomes: a Delphi study on the robot-assisted radical prostatectomy

OBJECTIVE

To develop an assessment instrument for the evaluation of surgical videos to elucidate the association between surgical skills and postoperative outcomes after a robot-assisted radical prostatectomy (RARP).

DESIGN

A Delphi study consisting of two consecutive online surveys and a consensus group meeting.

SETTING

Urology departments of general, teaching and university hospitals in the Netherlands.

PARTICIPANTS

All Dutch urologists with a specialization in RARP.

RESULTS

Of 18 invited experts, 12 (67%) participated in the first online survey. In the second round, 9 of the 18 invited experts participated (50%). The Delphi meeting was attended by 5 of the 18 (27%) invited experts. The panel identified seven surgical steps with a possible association to postoperative outcomes. The experts also expected an association between adverse postoperative outcomes and the frequency of camera removals, the number of stitches placed, the amount of bleeding, and the extent of coagulation. These factors were incorporated into an assessment instrument.

CONCLUSIONS

Experts in the field of RARP achieved consensus on 7 surgical steps and 4 aspects of the RARP procedure that may be related to adverse postoperative outcomes. The resulting assessment instrument will be tested in future research to determine its validity.

How Histopathologic Tumor Extent and Patterns of Recurrence Data Inform the Development of Radiation Therapy Treatment Volumes in Solid Malignancies

The ability to deliver highly conformal radiation therapy using intensity-modulated radiation therapy and particle therapy provides for new opportunities to improve patient outcomes by reducing treatment-related morbidities following radiation therapy. By reducing the volume of normal tissue exposed to radiation therapy (RT), while also allowing for the opportunity to escalate the dose of RT delivered to the tumor, use of conformal RT delivery should also provide the possibility of expanding the therapeutic index of radiotherapy. However, the ability to safely and confidently deliver conformal RT is largely dependent on our ability to clearly define the clinical target volume for radiation therapy, which requires an in-depth knowledge of histopathologic extent of different tumor types, as well as patterns of recurrence data. In this article, we provide a comprehensive review of the histopathologic and radiographic data that provide the basis for evidence-based guidelines for clinical tumor volume delineation.

The Changing Paradigm of Radiotherapy in the Elderly Population

There is increasing awareness of the special needs for care of the elderly cancer patient. Newer precise conformal radiotherapy techniques allow the safe delivery of higher doses of radiotherapy to the target tumor while reducing the dose to surrounding critical organs. This has led to a shortening of radiotherapy protocols for both curative and palliative indications. We review these novel techniques and protocols and the published clinical studies that include elderly patients treated with these techniques. Despite the fact that the elderly are a growing significant proportion of cancer patients, and the need for radiotherapy in the elderly is expected to rise with increasing life expectancy, they are underrepresented in most clinical studies of radiotherapy, and there are few studies specifically investigating radiotherapy in the elderly. The treatment of early-stage primary lung cancer with stereotactic body radiotherapy is a prime example how new highly conformal techniques and shortened treatment protocols are changing the approach to radiotherapy in the elderly. With improved imaging and radiotherapy treatment precision, it is expected that such techniques will become increasingly used in other cancer sites. It is important for radiation oncologists to be aware of the special needs of the elderly cancer patient and in particular to assess these patients based on functional status and not only chronological age. In addition, geriatric oncologists should be aware of modern radiotherapy techniques that can be particularly appropriate for the elderly patient.

Managing an Older Adult with Cancer: Considerations for Radiation Oncologists

Older adults with cancer present a unique set of management complexities for oncologists and radiation oncologists. Prognosis and resilience to cancer treatments are notably dependent on the presence or risk of "geriatric syndromes," in addition to cancer stage and histology. Recognition, proper evaluation, and management of these conditions in conjunction with management of the cancer itself are critical and can be accomplished by utilization of various geriatric assessment tools. Here we review principles of the geriatric assessment, common geriatric syndromes, and application of these concepts to multidisciplinary oncologic treatment. Older patients may experience toxicities related to treatments that impact treatment effectiveness, quality of life, treatment-related mortality, and treatment compliance. Treatment-related burdens from radiotherapy are increasingly important considerations and include procedural demands, travel, costs, and temporary or permanent loss of functional independence. An overall approach to delivering radiotherapy to an older cancer patient requires a comprehensive assessment of both physical and nonphysical factors that may impact treatment outcome. Patient and family-centered communication is also an important part of developing a shared understanding of illness and reasonable expectations of treatment.

Biodistribution of gold nanoparticles in BBN-induced muscle-invasive bladder cancer in mice

Bladder-sparing options are being developed for muscle-invasive bladder cancer in place of radical cystectomy, including the combination of chemotherapy and radiation therapy. We reasoned that improving the radiotherapy component of chemoradiation could improve the control of locally advanced disease. Previously, we showed that gold nanoparticles (AuNPs) are potent enhancers of radiation therapy. We hypothesized that if AuNPs were to preferentially localize to bladder tumors, they may be used to enhance the radiation component of muscle-invasive bladder tumor therapy. Mice were treated with the carcinogen N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) for 17, 20, and 22 weeks - long enough to induce muscle-invasive tumors. Mice were then anesthetized and injected intravenously with 1.9 nm AuNPs of which most were rapidly cleared from the blood and excreted after a 30-50 minute residence time in the bladder. We found AuNPs distributed throughout the bladder wall, but most of the AuNPs were associated with the stroma surrounding the tumor cells or extracellular keratin produced by the tumor cells. There were relatively few AuNPs in the tumor cells themselves. The AuNPs therefore localized to tumor-associated stroma and this tumor specificity might be useful for specific X-ray dose enhancement therapy of muscle-invasive bladder carcinomas.