Long-term Renal Function Outcomes After Stereotactic Ablative Body Radiotherapy for Primary Renal Cell Carcinoma Including Patients with a Solitary Kidney: A Report from the International Radiosurgery Oncology Consortium of the Kidney

BACKGROUND AND OBJECTIVE

Renal function preservation is particularly important following nonoperative treatment of localized renal cell carcinoma (RCC) since patients are often older with medical comorbidities. Our objective was to report long-term renal function outcomes after stereotactic ablative radiotherapy (SABR) including patients with a solitary kidney.

METHODS

Patients with primary RCC treated with SABR with ≥2 yr of follow-up at 12 International Radiosurgery Consortium for Kidney institutions were included. Renal function was measured by estimated glomerular filtration rate (eGFR).

KEY FINDINGS AND LIMITATIONS

In total, 190 patients (56 with a solitary kidney) underwent SABR and were followed for a median of 5.0 yr (interquartile range [IQR]: 3.4-6.8). In patients with a solitary kidney versus bilateral kidneys, pre-SABR eGFR (mean [standard deviation]) was 61.1 (23.2) versus 58.0 (22.3) ml/min (p = 0.32) and the median tumor size was 3.65 cm (IQR: 2.59-4.50 cm) versus 4.00 cm (IQR: 3.00-5.00 cm; p = 0.026). At 5 yr after SABR, eGFR decreased by -14.5 (7.6) and -13.3 (15.9) ml/min (p = 0.67), respectively, and there were similar rates of post-SABR dialysis (3.6% [n = 2/56] vs 3.7% [n = 5/134]). A multivariable analysis demonstrated that increasing tumor size (odds ratio [OR] per 1 cm: 1.57; 95% confidence interval [CI]: 1.14-2.16, p = 0.0055) and baseline eGFR (OR per 10 ml/min: 1.30; 95% CI: 1.02-1.66, p = 0.034) were associated with an eGFR decline of ≥15 ml/min at 1 yr.

CONCLUSIONS AND CLINICAL IMPLICATIONS

With long-term follow-up after SABR, kidney function decline remains moderate, with no observed difference between patients with a solitary kidney and bilateral kidneys. Tumor size and baseline eGFR are dominant factors predictive of long-term renal function decline.

PATIENT SUMMARY

With long-term follow-up, stereotactic ablative radiotherapy (SABR) yields moderate long-term renal function decline and low dialysis rates even in patients with a solitary kidney. SABR thus represents a promising noninvasive, nephron-sparing option for patients with localized renal cell carcinoma.

Evaluation of Volumetric Response Assessment From SABR for Renal Cell Carcinoma

PURPOSE

SABR is increasingly used to treat renal cell carcinoma (RCC). However, the optimal method to assess treatment response is unclear. We aimed to quantify changes in both volume and maximum linear size of tumors after SABR and evaluate the utility of the 2 approaches in treatment response assessment.

METHODS AND MATERIALS

We retrospectively studied patients with RCC treated with SABR at our institution between 2013 and 2020. All available follow-up computed tomography scans were aligned, and tumors were contoured on all scans. Volume and maximum linear size were measured at each follow-up, relative to these measurements at the time of computed tomography simulation.

RESULTS

Twenty-four patients with 25 tumors were included. Median follow-up was 32 months (range, 16-67). Nineteen tumors (76%) had 30% volumetric response at a median time of 7 months after SABR, and 12 tumors (48%) had 30% decrease in maximum linear size at a median time of 16 months. Eighteen tumors (72%) decreased in volume on first follow-up scan and continued to shrink, and 5 tumors (20%) displayed transient growth after SABR (average 24% increase in volume). Compared with T1a tumors, T1b or larger tumors were more likely to have transient growth (8% vs 33%; P = .16) and had higher average relative volume 24 months after SABR (0.47 vs 0.8; P = .022).

CONCLUSIONS

Volume measurement results in more pronounced and earlier change compared with linear size measurement when assessing response to SABR. These findings may provide guidance when assessing treatment response for patients with RCC treated with SABR.

Mild hyperthermia with magnetic resonance- guided high intensity focused ultrasound combined with salvage chemoradiation for recurrent rectal cancer

INTRODUCTION

Pelvic recurrences from rectal cancer present a challenging clinical scenario. Hyperthermia represents an innovative treatment option in combination with concurrent chemoradiation to enhance therapeutic effect. We provide the initial results of a prospective single center feasibility study (NCT02528175) for patients undergoing rectal cancer retreatment using concurrent chemoradiation and mild hyperthermia with MR-guided high intensity focused ultrasound (MR-HIFU).

METHODS

All patients were deemed ineligible for salvage surgery and were evaluated in a multidisciplinary fashion with a surgical oncologist, radiation oncologist and medical oncologist. Radiation was delivered to a dose of 30.6 Gy in 1.8 Gy per fraction with concurrent capecitabine. MR-HIFU was delivered on days 1, 8 and 15 of concurrent chemoradiation. Our primary objective was feasibility and toxicity.

RESULTS

Six patients (total 11 screened) were treated with concurrent chemoradiation and mild hyperthermia with MR-HIFU. Tumor size varied between 3.1-16.6 cm. Patients spent an average of 228 min in the MRI suite and sonication with the external transducer lasted an average of 35 min. There were no complications on the day of the MR-HIFU procedure and all acute toxicities (no grade >/=3 toxicities) resolved after completion of treatment. There were no late grade >/=3 toxicities.

CONCLUSION

Mild hyperthermia with MR-HIFU, in combination with concurrent chemoradiation for appropriately selected patients, is safe for localized pelvic recurrences from rectal cancer. The potential for MR-HIFU to be applied in the recurrent setting in rectal cancer treatment requires further technical development and prospective evaluation.

Randomized Trial of Concomitant Hypofractionated Intensity Modulated Radiation Therapy Boost Versus Conventionally Fractionated Intensity Modulated Radiation Therapy Boost for Localized High-Risk Prostate Cancer (pHART2-RCT)

PURPOSE

The aim of this work is to report on the results of a phase 2 randomized trial of moderately hypofractionated (MH) versus conventionally fractionated (CF) radiation therapy to the prostate with elective nodal irradiation.

METHODS AND MATERIALS

This was a single-center, prospective, phase 2 randomized study. Patients with high-risk disease (cT3, prostate-specific antigen level >20 ng/mL, or Gleason score 8-10) were eligible. Patients were randomized to either MH using a simultaneous integrated boost (68 Gy in 25 fractions to prostate; 48 Gy to pelvis) or CF (46 Gy in 23 fractions with a sequential boost to the prostate of 32 Gy in 16 fractions), with long-term androgen deprivation therapy. The primary endpoint was grade ≥2 acute gastrointestinal (GI) and genitourinary (GU) toxicity (Common Terminology Criteria for Adverse Events version 3.0). Secondary endpoints included late GI and GU toxicity, quality of life, and oncologic outcomes.

RESULTS

One-hundred eighty patients were enrolled; 90 were randomized to and received MH and 90 to CF. The median follow-up was 67.4 months. Seventy-five patients (41.7%) experienced a grade ≥2 acute GI and/or GU toxicity, including 34 (37.8%) in the MH and 41 (45.6%) in the CF arms, respectively (P = .29). Late grade ≥2 GI (P = .07) and GU (P = .25) toxicity was not significantly different between arms; however, late grade ≥3 GI toxicity was worse in the MH group (P = .01). There were no statistically significant quality-of-life differences between the 2 treatments. There were no statistically significant differences observed in cumulative incidence of biochemical failure (P = .71) or distant metastasis (P = .31) and overall survival (P = .46).

CONCLUSIONS

MH to the prostate and pelvis with androgen deprivation therapy for men with high-risk localized prostate cancer was not significantly different than CF with regard to acute toxicity, quality of life, and oncologic efficacy. However, late grade ≥3 GI toxicity was more common in the MH arm.

The Evolution of Spinal Endoscopy: Design and Image Analysis of a Single-Use Digital Endoscope Versus Traditional Optic Endoscope

Spinal endoscopy has evolved significantly since its inception, offering minimally invasive solutions for various spinal pathologies. This study introduces a promising innovation in spinal endoscopy-a single-use digital endoscope designed to overcome the drawbacks of traditional optic endoscopes. Traditional endoscopes, despite their utility, present challenges such as fragility, complex disinfection processes, weight issues, and susceptibility to mechanical malfunctions. The digital endoscope, with its disposable nature, lighter weight, and improved image quality, aims to enhance surgical procedures and patient safety. The digital endoscope system comprises a 30-degree 1000 × 1000 pixel resolution camera sensor with a 4.3 mm working channel, and LED light sources replacing optical fibers. The all-in-one touch screen tablet serves as the host computer, providing portability and simplified operation. Image comparisons between the digital and optic endoscopes revealed advantages in the form of increased field of view, lesser distortion, greater close-range resolution, and enhanced luminance. The single-use digital endoscope demonstrates great potential for revolutionizing spine endoscopic surgeries, offering convenience, safety, and superior imaging capabilities compared to traditional optic endoscopes.

Assessment of Cement Leakage in Decompressed Percutaneous Kyphoplasty

Symptomatic osteoporotic compression fractures are commonly addressed through vertebroplasty and kyphoplasty. However, cement leakage poses a significant risk of neurological damage. We introduced "aspiration percutaneous kyphoplasty", also known as "decompressed kyphoplasty", as a method to mitigate cement leakage and conducted a comparative analysis with high viscosity cement vertebroplasty. We conducted a retrospective study that included 136 patients with single-level osteoporotic compression fractures. Among them, 70 patients underwent high viscosity cement vertebroplasty, while 66 patients received decompressed percutaneous kyphoplasty with low-viscosity cement. Comparison parameters included cement leakage rates, kyphotic angle alterations, and the occurrence of adjacent segment fractures. The overall cement leakage rate favored the decompressed kyphoplasty group (9.1% vs. 18.6%), although statistical significance was not achieved (p = 0.111). Nonetheless, the risk of intradiscal leakage significantly reduced in the decompressed kyphoplasty cohort (p = 0.011), which was particularly evident in cases lacking the preoperative cleft sign on X-rays. Kyphotic angle changes and the risk of adjacent segment collapse exhibited similar outcomes (p = 0.739 and 0.522, respectively). We concluded that decompressed kyphoplasty demonstrates efficacy in reducing intradiscal cement leakage, particularly benefiting patients without the preoperative cleft sign on X-rays by preventing intradiscal leakage.

To Boost or Not to Boost: Pooled Analyses From 2-Fraction SABR Trials for Localized Prostate Cancer

PURPOSE

Focal boost to dominant intraprostatic lesion (DIL) is an approach for dose escalation in prostate radiation therapy. In this study, we aimed to report the outcomes of 2-fraction SABR ± DIL boost.

METHODS AND MATERIALS

We included 60 patients with low- to intermediate-risk prostate cancer enrolled in 2 phase 2 trials (30 patients in each trial). In the 2STAR trial (NCT02031328), 26 Gy (equivalent dose in 2-Gy fractions = 105.4 Gy) was delivered to the prostate. In the 2SMART trial (NCT03588819), 26 Gy was delivered to the prostate, with up to 32 Gy boost to magnetic resonance imaging-defined DIL (equivalent dose in 2-Gy fractions = 156.4 Gy). The reported outcomes included prostate-specific antigen (PSA) response (ie, <0.4 ng/mL) at 4 years (4yrPSARR), biochemical failure (BF), acute and late toxicities, and quality of life (QOL).

RESULTS

In 2SMART, median DIL D99% of 32.3 Gy was delivered. Median follow-up was 72.7 months (range, 69.1-75.) in 2STAR and 43.6 months (range, 38.7-49.5) in 2SMART. The 4yrPSARR was 57% (17/30) in 2STAR and 63% (15/24) in 2SMART (P = 0.7). The 4-year cumulative BF was 0% in 2STAR and 8.3% in 2SMART (P = 0.1). The 6-year BF in 2STAR was 3.5%. For genitourinary toxicities, there were differences in grade ≥1 urinary urgency in the acute (0% vs 47%; P < .001) and late settings (10% vs 67%; P < .001) favoring 2STAR. For urinary QOL, no difference was observed in the acute setting, but lower proportion in 2STAR had minimal clinically important changes in urinary QOL score in the late setting (21% vs 50%; P = .03). There were no significant differences in gastrointestinal and sexual toxicities and QOL in both acute and late settings between the 2 trials.

CONCLUSIONS

This study presents the first prospective data comparing 2-fraction prostate SABR ± DIL boost. The addition of DIL boost resulted in similar medium-term efficacy (in 4yrPSARR and BF), with impact on late urinary QOL outcomes.

Dosimetric correlates of toxicities and quality of life following two-fraction stereotactic ablative radiotherapy (SABR) for prostate cancer

PURPOSE

There is no evidence-based data to guide dose constraints in two-fraction prostate stereotactic ablative radiotherapy (SABR). Using individual patient-data from two prospective trials, we aimed to correlate dosimetric parameters with toxicities and quality of life (QoL) outcomes.

MATERIALS AND METHODS

We included 60 patients who had two-fraction prostate SABR in the 2STAR (NCT02031328) and 2SMART (NCT03588819) trials. The prescribed dose was 26 Gy to the prostate+/-32 Gy boost to the dominant intraprostatic lesions. Toxicities and QoL data were prospectively collected using CTCAEv4 and EPIC-26 questionnaire. The outcomes evaluated were acute and late grade ≥ 2 toxicities, and late minimal clinical important changes (MCIC) in QoL domains. Dosimetric parameters for bladder, urethra, rectum, and penile bulb were evaluated.

RESULTS

The median follow-up was 56 months (range: 39-78 months). The cumulative incidence of grade ≥ 2 genitourinary (GU), gastrointestinal (GI), and sexual toxicities were 62%, 3%, and 17% respectively in the acute setting (<3 months), and 57%, 15%, and 52% respectively in late setting (>6 months). There were 36%, 28%, and 29% patients who had late MCIC in urinary, bowel and sexual QoL outcomes respectively. Bladder 0.5 cc was significant predictor for late grade ≥ 2 GU toxicities, with optimal cut-off of 25.5 Gy. Penile bulb D5cc was associated of late grade ≥ 2 sexual toxicities (no optimal cut-off was identified). No dosimetric parameters were identified to be associated with other outcomes.

CONCLUSION

Using real-life patient data from prospective trials with medium-term follow-up, we identified additional dose constraints that may mitigate the risk of late treatment-related toxicities for two-fraction prostate SABR.

Application of machine learning and its effects on the development of a nursing guidance mobile app for sarcopenia

BACKGROUND

Aging leads to changes in the body system, such as sarcopenia. This can result in several health issues, particularly physical and mobility dysfunction. Asian people typically have little awareness of sarcopenia. Thus, this study incorporated nursing instruction into the mobile application design to allow users to easily learn about sarcopenia.

OBJECTIVE

This study evaluated a model for predicting high-risk populations for sarcopenia in home settings. We further developed a sarcopenia nursing guidance mobile application and assessed the effectiveness of this application in influencing sarcopenia-related knowledge and self-care awareness among participants.

METHODS

Using a one-group pretest-posttest design, data were collected from 120 participants at a teaching hospital in northern Taiwan. This study used an artificial intelligence algorithm to evaluate a model for predicting high-risk populations for sarcopenia. We developed and assessed the sarcopenia nursing guidance mobile application using a questionnaire based on the Mobile Application Rating Scale.

RESULTS

The application developed in this study enhanced participants' sarcopenia-related knowledge and awareness regarding self-care. After the three-month intervention, the knowledge and awareness was effectively increase, total score was from 4.15 ± 2.35 to 6.65 ± 0.85 and were significant for all questionnaire items (p values < 0.05). On average, 96.1% of the participants were satisfied with the mobile app. The artificial intelligence algorithm positively evaluated the home-use model for predicting high-risk sarcopenia groups.

CONCLUSIONS

The mobile application of the sarcopenia nursing guidance for public use in home settings may help alleviate sarcopenia symptoms and reduce complications by enhancing individuals' self-care awareness and ability.

TRIAL REGISTRATION

NCT05363033, registered on 02/05/2022.

Radiotherapy for Liver Cancer: An International Multi-Centre Pooled Analysis of 925 Cases

PURPOSE/OBJECTIVE(S)

Primary and secondary liver cancer incidence is growing and has a poor prognosis. The standard use of radiation has been hampered by studies with a wide range of patients, different management protocols and varied outcomes. To overcome this heterogeneity in the literature, larger and higher-level trials are warranted, but, so far, have been difficult to implement. Therefore, pooled analyses may offer the best way to determine the benefit of radiation, identify treatment parameters needed to optimize treatment techniques, and identify patient factors that allow for better patient selection.

MATERIALS/METHODS

Patients with liver cancer treated by radiotherapy at centers in Canada, United States and Australia was pooled. Patient and treatment characteristics were noted, as well as the clinical outcomes of local control within 1 year, recurrence and mortality. Stepwise Cox proportional hazards models were used to identify significant predictors for recurrence and mortality. Patients were stratified by center, and primary versus metastatic disease.

RESULTS

A total of 925 patients were included in this study. Mean age was 67 years, and 45% had a primary diagnosis of hepatocellular carcinoma. 1-year local control rate was 80%. Median survival was 1.8 years (1.9 years for primary liver cancer, and 1.4 years for metastatic liver cancer). Higher total dose and BED was associated with better survival. Median time to recurrence was 1.5 years. Higher total dose was associated with lower risk of recurrence CONCLUSION: As one of the largest pooled analyses in hepatic cancer, this international multi-center study provides pragmatic data on clinical outcomes of patients receiving radiotherapy for liver cancer. This database may assist in better selection of patients for future studies and answer questions such as what is the optimal dose and which patients benefit from treatment.

5-Year Renal Function Outcomes after SABR for Primary Renal Cell Carcinoma: A Report from the International Radiosurgery Oncology Consortium of the Kidney (IROCK)

PURPOSE/OBJECTIVE(S)

Renal cell carcinoma (RCC) presents uncommonly in patients with a congenital solitary kidney or prior contralateral nephrectomy. The objective of this study was to compare renal function outcomes of stereotactic ablative body radiotherapy (SABR) in patients with solitary vs. bilateral kidneys.

MATERIALS/METHODS

Patients with primary RCC with ≥2 years of follow-up at 12 participating International Radiosurgery Consortium for Kidney (IROCK) institutions were included. Patients with upper tract urothelial carcinoma or metastatic disease were excluded. Renal function was measured by estimated glomerular filtration rate (eGFR). For patients where eGFR was not recorded, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation was used to estimate eGFR based on known creatinine. Baseline characteristics and renal function outcomes were compared between solitary vs. bilateral kidneys. Multivariable logistic regression was used to identify factors predictive of eGFR decline ≥ 15 mL/min and any eGFR increase evaluated at 1-year post-SABR.

RESULTS

One hundred and ninety patients with solitary (n = 56) or bilateral kidneys (n = 134) underwent SABR and were followed for a median of 5.0 years (IQR: 3.4-6.8). Pre-SABR eGFR (mean ± SD) was similar in patients with solitary (61.1 ± 23.2 mL/min) vs. bilateral kidneys (58.0 ± 22.3 mL/min, p = 0.324). Mean tumor size was 3.70 ± 1.40 cm in solitary and 4.35 ± 2.50 cm in bilateral kidneys (p = 0.026). After SABR, an initial compensatory increase in eGFR was observed in both cohorts (22.7% solitary and 17.7% bilateral at 1 year). This compensatory increase persisted in patients with bilateral but not a solitary kidney (10.3% vs. 0% at 3-years and 21.1% vs. 0% at 5-years, respectively). At 5-years post-SABR, eGFR decreased by -14.5 ± 7.6 in solitary and -13.3 ± 15.9 mL/min in bilateral kidneys (p = 0.665). At all timepoints assessed, there were no significant differences in eGFR decline between solitary vs. bilateral cohorts (all p > 0.05). There were also no significant differences in post-SABR end-stage renal disease (7.1% vs. 6.7%) or dialysis (3.6% vs. 3.7%) in solitary vs. bilateral, respectively. Multivariable analysis demonstrated that increasing tumor size (OR per 1 cm: 1.57; 95% CI: 1.14-2.16, p = 0.006) and baseline eGFR (OR per 10 mL/min: 1.30; 95% CI: 1.02-1.66, p = 0.034) was more likely to be associated with eGFR decline ≥ 15 mL/min. There was no significant association between solitary vs. bilateral kidney and eGFR decline (OR: 1.22; 95% CI: 0.45-3.34, p = 0.693).

CONCLUSION

There was no observed difference between renal function outcomes in patients with a solitary vs. bilateral kidneys. While larger tumor size may increase the risk of eGFR decline post-SABR, treatment of a solitary kidney does not appear to increase the risk of renal dysfunction long-term.

Real-World Experience of Intensity Modulated Radiation Therapy and Concurrent Chemotherapy for Anal Cancer with Long-Term Follow up and Clinical Outcomes

PURPOSE/OBJECTIVE(S)

The standard treatment for epidermoid anal cancer (AC) is concurrent chemoradiation (CRT). Here we present real world evidence of the safety and outcomes of AC patients managed by IMRT and concurrent chemotherapy at a single academic cancer center.

MATERIALS/METHODS

We retrospectively reviewed the outcomes of 180 AC patients treated with definitive CRT between 2011 and 2018. Patients were managed according to a prospectively designed protocol of IMRT with radiation dose escalated according to tumor stage: 50.4, 55.8 and 63 Gy for T1, T2 and T3/T4 disease respectively, and 36 Gy for elective nodal RT. Involved nodes were given the same dose based on T category. Concurrent chemotherapy consisted of two cycles of mitomycin C (MMC, 12 mg/m2) and 5-fluorouracil (5FU, 1000 mg/m2/day x 4 days) given on week 1 and 5. There was no planned treatment break. Univariate and multivariate analysis for outcomes were performed using Cox proportional hazard method and likelihood ratio statistics. Overall survival (OS) disease free (DFS), colostomy-free survival (CFS) and local failure rates (LFR) were described by Kaplan-Meier methods.

RESULTS

There were 128 female and 52 male patients with a median age of 64 (IQR 55-74). The median size of the primary was 4.0 cm (0.6-11.0 cm). There were 18 T1, 91 T2, 38 T3 and 33 T4 lesions; 50.6% (91/180) of the patients had N0 disease. Thirteen (7.2%) did not receive concurrent chemotherapy, and 16 (8.9%) failed to complete treatment as planned. Forty-three (23.9%) patients had a treatment gap >5 (6-33) days. Eighteen of 147 (12%) with T1-3 disease failed locally, LF was observed in 13/33 (39%) T4 lesions (P = 0.0002). The 5-year OS, DFS, CFS and LFR were 85.1%, 75.6%, 87.6% and 15.5% respectively. On multivariate analysis, increasing age and N+ disease were significant for worse OS, and increasing size of the primary tumor was the only significant factor for worse DFS, CFS and LFR. Grade ≥3 acute toxicities were observed in 42.8% of patients, with grade ≥3 neutropenia and febrile neutropenia observed in 18.9% and 13.9% of patients respectively. Six patients (3.3%) died of acute toxicities. Thirteen (7%) patients experienced grade ≥3 late toxicities.

CONCLUSION

Size of the primary appears to be the most important determinant of outcome following standard CRT using IMRT for AC. Despite IMRT, almost 1 in 4 patients required a treatment break, and over 40% experienced grade ≥3 acute toxicities including neutropenia and febrile neutropenia. Future studies with RT dose escalation or de-escalation, stratifying patients based on tumor size, HPV status and molecular markers are necessary to improve outcomes and decrease treatment related toxicity.

Dosimetric Parameters Predictive of Treatment-Related Toxicity in High Dose-Rate Brachytherapy as Monotherapy for Prostate Cancer

PURPOSE/OBJECTIVE(S)

High dose-rate (HDR) brachytherapy as monotherapy is an effective treatment for patients with low- and intermediate-risk prostate cancer and is increasingly being offered as a 2-fraction protocol. There is a lack of consensus on the optimal dosimetric planning parameters to use, or whether there is any benefit summating dosimetric parameters from more than one implant. Our goal is to determine planning parameters associated with disease control, toxicity and health-related quality of life (HRQOL).

MATERIALS/METHODS

Data were collected on 83 patients with low- and intermediate-risk prostate cancer who received 2 fractions of 13.5 Gy HDR brachytherapy without androgen-deprivation therapy as part of a randomized phase II clinical trial. An in-house deformable, registration algorithm was used to co-register and dose-summate the plans from both implants for each patient. Acute and late GU and GI toxicities were measured using CTCAE 4.0 and HRQOL was measured in urinary, bowel, sexual and hormonal domains using the EPIC scores. Treatment efficacy was assessed through PSA measurement and imaging with or without biopsy where indicated. Covariates included baseline clinical factors, disease characteristics and treatment dosimetric parameters. Cox proportional hazards was performed to evaluate covariates impact on treatment toxicity and efficacy, and logistic regression analysis evaluated covariates impact on HRQOL.

RESULTS

Among the 83 patients, median prostate volume was 46.7cm3. Median summated planning target volume receiving 100% prescription dose (PTV V100%) was 97.4%, median PTV V150% 42.4% and median PTV V200% 15.5%. Median highest dose to the 1cm3 rectum (D1cc) was 66.9% of the prescription dose and median rectum V80% was 0.008cm3. Median urethral D1cc was 99.0% of the prescription dose, median urethral Dmax 121.7% and median urethral D10% 116.2%. Grade ≥2 GI toxicity was uncommon (3.7% acute and 8.5% late), but grade ≥2 GU toxicity was reported in 73.2% (acute) and 46.3% (late) patients. Rectum D1cc and V80% were found to be significantly associated with grade 2 or higher acute GI toxicity, while use of a-blocker at baseline was associated with grade ≥2 acute GU toxicity. Similarly, use of a-blocker was associated with late grade ≥2 GU toxicity, but with no dosimetric associations. No other variables were associated with treatment-related toxicities. Only rectum D1cc was significantly associated with changes in bowel EPIC scores. Estimated 5-year biochemical disease-free survival was 93.9% and 5-year cumulative incidence of local failure was 3.8%.

CONCLUSION

HDR monotherapy with 27 Gy delivered in 2 fractions in treatment of prostate cancer is well tolerated with high rates of disease control and minimal toxicity. Dose summation between 2 fractions of HDR brachytherapy is feasible, with rectal dose predicting acute GI toxicity. The lack of association between dose metrics and urinary toxicity raises the potential for further dose escalation.

Dosimetric Predictors of Toxicities and Quality of Life Following Two-Fraction Stereotactic Body Radiotherapy for Prostate Cancer

PURPOSE/OBJECTIVE(S)

There is emerging interest in two-fraction stereotactic body radiotherapy (2#SBRT) for localized prostate cancer. However, there is limited data to guide organs at risk (OAR) dose constraints in 2#SBRT. We aim to identify dosimetric predictors of toxicities and quality of life (QoL) using real life patient data from two prospective 2#SBRT trials.

MATERIALS/METHODS

We included 60 patients who had 2#SBRT in the 2STAR (NCT02031328) and 2SMART (NCT03588819) phase 2 trials. The prescribed dose was 26Gy to the prostate +/- focal boost of 32Gy to the dominant intraprostatic lesions. Toxicities and QoL data were prospectively collected using CTCAEv4 and EPIC26 questionnaires. For QoL, we reported the minimal clinical important changes (MCIC), defined as changes in QoL score of >0.5 standard deviation from baseline QoL score. We evaluated the bladder, urethra, rectum, and penile bulb dosimetry (urethra dosimetry only available in 30 patients in 2SMART trial). Some of the dosimetric parameters were log-transformed to normalize the distribution. Cox regression was used to identify dosimetric predictors for acute and late grade ≥2 GU toxicities. Logistic regression was used to identify dosimetric predictors for late MCIC in urinary, bowel and sexual QoL domains. Backward stepwise selection was used to identify significant dosimetric parameters. For GU toxicities and urinary QoL, three additional clinical factors (age, prostate volume and IPSS) were included in the final model as confounding factors. Receiver operating characteristics curve was used to identify cut-off for significant dosimetric parameters.

RESULTS

The median follow-up for the cohort was 56 months (range: 39-78 months). The cumulative acute and late grade ³2 GU toxicities were 62% (37/60) and 57% (34/60) respectively. No bladder or urethra dosimetric parameter was associated with acute grade ≥2 GU toxicities. Bladder D0.5cc was significant predictor of late grade ≥2 GU toxicities in univariate model (P = 0.05), but not in multivariate model. Baseline IPSS score was the single strongest predictor for late grade ≥2 GU toxicities (HR = 1.9; 95% CI = 1.1-3.4; P = 0.03). For late QoL outcomes, there were 36% (21/58), 28% (16/58), and 29% (17/58) of patients with MCIC in urinary, bowel and sexual QoL domains respectively. Bladder V10Gy was associated with late urinary MCIC in multivariate model after adjusting for clinical confounders (HR = 2.6, 95% CI = 1.1-6.6; P = 0.04). 48% (14/29) and 24% (7/29) of patients with bladder V10Gy>13.9% and V10Gy≤13.9% respectively had late urinary MCIC. No rectum and penile bulb dosimetry parameters was identified to be associated with late bowel or sexual QoL.

CONCLUSION

Using real life patient data from prospective clinical trials with medium term follow-up, we identified statistically significant bladder dosimetry parameter predictive of late urinary QoL. This finding could be useful to guide OAR dose constraints in prostate 2#SBRT trials.

Predictors of pathologic fracture and local recurrence following stereotactic body radiation therapy to 505 non-spine bone metastases

PURPOSE

Stereotactic Body Radiation Therapy (SBRT) is increasingly applied to treat non-spine bone metastases (NSBM) though data remains limited on this approach. In this retrospective study, we report outcomes and predictors of local failure (LF) and pathological fracture (PF) post-SBRT for NSBM using a mature single-institution database.

METHODS

Patients with NSBM treated with SBRT between 2011 and 2021 were identified. The primary objective was to assess the rates of radiographic LF. Secondary objectives were to assess the rates of in-field PF, overall survival (OS), and late grade ≥ 3 toxicity. Competing risks analysis was used to assess rates of LF and PF. Univariable regression and multivariable regression (MVR) were performed to investigate predictors of LF and PF.

RESULTS

A total of 373 patients with 505 NSBM were included in this study. Median follow-up was 26.5 months. The cumulative incidence of LF at 6, 12, and 24 months were 5.7%, 7.9%, and 12.6%, respectively. The cumulative incidence of PF at 6, 12, and 24 months were 3.8%, 6.1%, and 10.9%, respectively. Lytic NSBM (HR = 2.18; p < 0.01), a lower biologically effective dose (HR = 1.11 per 5 Gy10 decrease; p = 0.04), and a PTV ≥ 54 cc (HR = 4.32; p < 0.01) predicted for a higher risk of LF on MVR. Lytic NSBM (HR = 3.43; p < 0.01), mixed (lytic/sclerotic) lesions (HR = 2.70; p = 0.04), and rib metastases (HR = 2.68; p < 0.01) predicted for a higher risk of PF on MVR.

CONCLUSION

SBRT is an effective modality to treat NSBM with high rates of radiographic local control with an acceptable rate of PF. We identify predictors of both LF and PF that can serve to inform practice and trial design.

Impact of Aspiration Percutaneous Vertebroplasty in Reducing Bone Cement Leakage and Enhancing Distribution-An Ex Vivo Study in Goat Vertebrae

Osteoporosis-induced vertebral compression fracture (OVCF) occurs commonly in people over the age of 50, especially among menopausal women. Besides conservative therapy, minimally invasive percutaneous vertebroplasty (PVP) and kyphoplasty (PKP) have been widely used in clinical treatment and achieved good efficacy. However, the leakage of bone cement (CL) during vertebroplasty (PV) is a major risk that can cause (serious) complications such as compression of the spinal cord, pulmonary embolism, or even paraplegia. In this study, we introduced a new aspiration technique with standard PV procedures (APV) to ameliorate the risk of leakage with quantitative verifications of its effectiveness. APV intends to create a differential pressure to guide the direction of cement flow within the vertebrae. To test this technique, Nubian goats' ex vivo vertebral bodies (VBs) were used to simulate the PV surgical process in humans. Results show that the proposed APV has a lower leakage rate of 13% compared to the 53% of conventional PV. Additionally, the APV approach achieves more uniform cement distribution via the 9-score method with a value of 7 ± 1.30 in contrast to 4 ± 1.78 by conventional PV.

Risk-adjusted chemoradiation according to human papilloma viral status for anal cancer: a pilot study

Background and purpose

HPV-associated or positive (HPV+) anal cancer patients may have better outcome compared to those with HPV negative (HPV-) disease. We report a planned interim analysis of a prospective registry study that tailors chemoradiation (CRT) for anal cancer according to HPV status.

Materials and methods

HPV+ patients received de-escalated radiation doses of 45, 50.4 and 55.8 Gy, while HPV- received 50.4, 55.8 and 63 Gy for T1, T2 and T3/T4 disease respectively. Chemotherapy consisted of a single dose of mitomycin-C and oral capecitabine on days of RT. All patients were planned by VMAT following CT, PET/CT and MR simulation. This cohort (n = 24) had a minimum 24-month follow-up. Disease free survival (DFS) and local failure rates (LFR) were compared with 180 patients managed by standard CRT (2 cycles of mitomycin-C and 5-fluorouracil, radiation doses 50.4-63 Gy based on T-category) from 2011-2018. Propensity score comparison was performed using a retrospective to prospective 2 to 1 match based on tumor size and N-category.

Results

In the HPV+ cohort (n = 20), there were 2 local failures. Two of 4 HPV- patients failed locally. The 30-month DFS and LFR were 79% and 17% respectively. Similar DFS and LFR were observed in the retrospective (80% and 15% respectively) and matched patients (76% and 16% respectively). No grade ≥3 neutropenia and febrile neutropenia were observed in the registry cohort whereas 19% and 14% respectively were seen in the retrospective patients.

Conclusion

De-escalation of CRT for HPV+ anal cancer may result in decreased acute toxicities and similar cancer outcomes compared to standard CRT.

Adjuvant therapy for renal cell carcinoma: 2023 Canadian Kidney Cancer Forum consensus statement

INTRODUCTION

Several recent randomized trials evaluated the impact of adjuvant immune checkpoint inhibitor (ICI)-based therapy on post-surgical outcomes in renal cell carcinoma (RCC), with disparate results. The objective of this consensus statement is to provide data-driven guidance regarding the use of ICIs after complete resection of clear-cell RCC in a Canadian context.

METHODS

An expert panel of genitourinary medical oncologists, urologic oncologists, and radiation oncologists with expertise in RCC management was convened in a dedicated session during the 2022 Canadian Kidney Cancer Forum in Toronto, Canada. Topic statements on the management of patients after surgery for RCC, including counselling, risk stratification, indications for medical oncology referral, appropriate followup, eligibility and management for adjuvant ICIs, as well as treatment options for patients with recurrence who received adjuvant immunotherapy, were discussed. Participants were asked to vote if they agreed or disagreed with each statement. Consensus was achieved if greater than 75% of participants agreed with the topic statement.

RESULTS

A total of 22 RCC experts voted on 14 statements. Consensus was achieved on all topic statements. The panel felt patients with clear-cell RCC at increased risk of recurrence after surgery, as per the Keynote-564 group definitions, should be counselled about recurrence risk by a urologist, should be informed about the potential role of adjuvant ICI systemic therapy, and be offered referral to discuss risks and benefits with a medical oncologist. The panel felt that one year of pembrolizumab is currently the only regimen that should be considered if adjuvant therapy is selected. Panelists emphasized current opinions are based on disease-free survival given the available results. Significant uncertainty regarding the benefit and harms of adjuvant therapy remains, primarily due to a lack of consistent benefit observed across similar trials of adjuvant ICI-based therapies and immature overall survival (OS) data.

CONCLUSIONS

This consensus document provides guidance from Canadian RCC experts regarding the potential role of ICI-based adjuvant systemic therapy after surgery. This rapidly evolving field requires frequent evidence-based re-evaluation.

International Validation of the EORTC QLQ-ANL27, a Field Study to Test the Anal Cancer-Specific Health-Related Quality-of-Life Questionnaire

PURPOSE

The European Organisation for Research and Treatment of Cancer (EORTC) health-related quality of life questionnaire for anal cancer (QLQ-ANL27) supplements the EORTC cancer generic measure (QLQ-C30) to measure concerns specific to people with anal cancer treated with chemoradiotherapy. This study tested the psychometric properties and acceptability of the QLQ-ANL27.

METHODS AND MATERIALS

People with anal cancer were recruited from 15 countries to complete the QLQ-C30 and QLQ-ANL27 and provide feedback on the QLQ-ANL27. Item responses, scale structure (multitrait scaling, factor analysis), reliability (internal consistency and reproducibility) and sensitivity (known group comparisons and responsiveness to change) of the QLQ-ANL27 were evaluated.

RESULTS

Data from 382 people were included in the analyses. The EORTC QLQ-ANL27 was acceptable, comprehensive, and easy to complete, taking an average 8 minutes to complete. Psychometric analyses supported the EORTC QLQ-ANL27 items and reliability (Cronbach's α ranging from 0.71-0.93 and test-retest coefficients above 0.7) and validity of the scales (particularly nonstoma bowel symptoms and pain/discomfort). Most scales distinguished people according to treatment phase and performance status. Bowel (nonstoma), pain/discomfort, and vaginal symptoms were sensitive to deteriorations over time. The stoma-related scales remained untested because of low numbers of people with a stoma. Revisions to the scoring and question ordering of the sexual items were proposed.

CONCLUSIONS

The QLQ-ANL27 has good psychometric properties and is available in 16 languages for people treated with chemoradiotherapy for anal cancer. It is used in clinical trials and has a potential role in clinical practice.

Two-fraction stereotactic MRI-guided ablative radiotherapy with simultaneous boost to dominant intraprostatic lesion: Results from the 2SMART phase 2 trial

349

Background: Prostate stereotactic ablative radiotherapy (SABR) for localised prostate cancer is commonly delivered over 5 fractions. Focal boost to the dominant intraprostatic lesion (DIL) seen on multiparametric magnetic resonance imaging (mpMRI) is an approach for dose-escalation in prostate SABR. This is the first report of the outcomes of the 2SMART trial, a phase 2 single-arm study using 2-fraction prostate SABR with DIL boost. Methods: Men with low to intermediate risk prostate cancer were enrolled in the study. Three gold fiducial markers were inserted for image guidance. The clinical target volume (CTV) included the prostate gland, and the planning target volume (PTV) was a 2mm expansion antero-posterior and laterally, and 2.5mm supero-inferiorly. The DIL was contoured on fused mpMRI. The prescribed dose was 26Gy in 2 fractions (EQD2 110Gy, α/β of 1.4) to the CTV, and up to 32Gy in 2 fractions (EQD2 164Gy) to the DIL as long as the dose constraints for the organs at risks were not exceeded. Each fraction was delivered 1 week apart. Daily image guidance with cone-beam computed tomography was used pre- and post-treatment. The primary endpoint was acute (≤3 months) changes in quality of life (QOL), assessed using the EPIC questionnaire. Minimal clinically important change (MCIC) in QOL was defined as an EPIC score decrease of >0.5 standard deviation of the baseline EPIC score for each domain. Secondary endpoints were acute and late toxicities (assessed using CTCAEv4), and biochemical failure (based on Phoenix criteria). Results: 30 men were enrolled in the study, of which 2 (7%) had low risk and 28 (93%) had intermediate risk prostate cancer. The median follow-up was 44 months (range: 39-49 months). The median PSA nadir was 0.2ng/mL, with median time to nadir of 37 months. One patient (3%) had biochemical failure at 44 months post-treatment. 1 (3%) and 17 (57%) had acute Grade 2 GU and GI toxicities, while 3 (10%) and 15 (50%) had late (>6 months) Grade 2 GU and GI toxicities. No acute or late Grade ≥3 GU or GI was reported. 10 (33%), 6 (20%), and 3 (10%) men had acute MCIC in urinary, bowel and sexual domains respectively. 15 (50%), 9 (30%) and 13 (43%) had late MCIC in urinary, bowel and sexual domain respectively. Conclusions: Two-fraction prostate SABR with DIL boost is a safe approach for dose-escalation for localised prostate cancer, with minimal impact on acute QOL, and no grade 3-4 toxicities. Clinical trial information: NCT03588819 .

Phase II trial of cytoreductive stereotactic hypofractionated radiotherapy with combination ipilimumab/nivolumab for metastatic kidney cancer (CYTOSHRINK)

TPS750

Background: Randomized data from the interferon era demonstrated survival benefits of cytoreductive nephrectomy (CN) in patients with metastatic renal cell carcinoma (mRCC). Results from SURTIME and CARMENA, conducted in the VEGF-targeted therapy era, have challenged the routine use of upfront CN in most IMDC intermediate and poor risk patients. Furthermore, the treatment landscape in mRCC now includes multiple first-line doublet combination immunotherapy approvals. The Checkmate-214 trial showed that intermediate/poor risk patients have improved overall survival and durable objective responses with ipilimumab and nivolumab (I/N) compared to sunitinib. However, patients with a primary kidney lesion in situ appeared to have less benefit than patients with prior nephrectomy. Stereotactic body radiation therapy (SBRT) provides a convenient method for cytoreduction of the primary kidney lesion and may induce an enhanced systemic anti-tumor immune response. We hypothesize that SBRT to the primary kidney mass will enhance the efficacy of I/N compared to standard of care I/N alone in this unique subset of de novo mRCC patients. We also hypothesize that the combination of SBRT and I/N will lead to upregulation of key components of immune modulation as well as unique perturbation of the host gut microbiome compared to I/N alone. Methods: This phase II trial randomizes untreated mRCC patients in a 2:1 fashion to I/N plus SBRT (30-40 Gy in 5 fractions) to the primary kidney mass between cycles 1 and 2 (experimental arm, E), versus standard of care I/N alone (standard arm, S). Eligible patients have biopsy-proven mRCC (any histology) and IMDC intermediate/poor risk disease. Patients with a primary kidney lesion ≥ 20cm, previous abdominal radiation precluding SBRT, or who have a contraindication to I/N are excluded. The primary objective is to compare the efficacy of I/N plus SBRT versus I/N alone, as determined by the hazard ratio for progression free survival (PFS). Secondary objectives include evaluation of safety, overall survival, objective response rate, and health-related quality of life. Exploratory analyses include: (1) immune and genomic profiling of liquid biopsies; (2) transcriptional profiling of baseline tumor biopsies; and (3) interrogation of the gut microbiome and bacterial functionality. Blood and fecal samples will be prospectively collected at baseline, prior to cycle 2 of each arm, and at time of disease progression or the 12-month mark, whichever comes first. Up to 78 patients will be enrolled under the assumption of an improved 12-month PFS from 50% (S) to 75% (E), using a two-sided α=0.1, power=80%, and accounting for loss-to-follow-up and stratification using IMDC criteria 1-2 vs 3-6. Trial is enrolling in Canada and Australia. Clinical trial information: NCT04090710 .

Designing an eSports intervention for middle-aged and older adults in Hong Kong: Social marketing approach

This study examined the perceptions and experiences of middle-aged and older adult participants in electronic sports (eSports) in Hong Kong (HK), China, by using the social marketing (SM) approach. This qualitative study applied SM approach to the design of a center-based eSports intervention for middle-aged and older adults in HK. Interviews were conducted with 39 adults stratified in terms of age (i.e., 45-64 vs. ≥65 years) and experience with eSports. Ten administrators working in community elderly centers were invited for semistructured interviews. Thematic analysis was performed on the data by incorporating SM. Main findings are presented in terms of five P's. The product component of an eSports intervention includes the foundation of eSports (e.g., safety, eSports training), suitable games for older adults, and professional equipment (e.g., large-screen devices and motion-controlled Nintendo Switches). The price component comprises affordability and the frequency and duration of each eSport session, and the place component includes accessibility and spaces to play eSports. The promotion component should be educational in nature and can incorporate free trials and gaming days, short films about older adults playing eSports, promotional channels, physical evidence and annual eSports competitions. The people component consists of support from administrators and the center in charge, the availability of skilled program instructors and staff, and appropriate partnering, team sizes and instructor-to-participant ratios. The 5P's enhance the design of future center-based eSports interventions and can help researchers and practitioners determine which aspects encourage middle-aged and older adults to participate in eSports.

Stereotactic Body Radiotherapy for Renal Cell Carcinoma: Oncological and Renal Function Outcomes

AIMS

To evaluate oncological and renal function outcomes of stereotactic body radiotherapy (SBRT) for medically inoperable patients with localised renal cell carcinoma.

MATERIALS AND METHODS

Consecutive patients treated with curative intent SBRT (30-45 Gy in five fractions or 42 Gy in three fractions) were included. Data on local control (Response Evaluation Criteria in Solid Tumors [RECIST] v1.1), distant metastasis, impact on estimated glomerular filtration rate (eGFR) and proportional ipsilateral and contralateral renal functions (measured through renal scans) were collected. Univariate and multivariable analyses were conducted to determine association of variables with oncological and renal function outcomes.

RESULTS

Seventy-four patients were analysed. The median follow-up was 27.8 months (interquartile range 17.6-41.7). Fifty-seven per cent had tumours ≥ T1b. One-, 2- and 4-year cumulative incidence of local failure was 5.85, 7.77 and 7.77%, respectively. The cumulative incidence of distant metastasis at 2 years was 4.24%. On multivariable analysis, a lower planning target volume (PTV) mean dose (P = 0.019) and a larger PTV (P = 0.005) were significantly associated with the risk of developing local failure. A lower PTV maximum dose (P = 0.039) was significantly associated with the risk of developing distant metastasis. The median change in global eGFR (ml/min) from pre-SBRT levels was -7.0 (interquartile range -14.5 to -1.0) at 1 year and -11.5 (interquartile range -19.5 to -4.0) at 2 years. The proportion of ipsilateral (differential) renal function decreased over time from 47% of overall renal function pre-SBRT to 36% at 2 years, whereas the proportion of contralateral renal function correspondingly improved. On multivariable analysis, a higher volume of uninvolved renal cortex (P < 0.0001) was significantly associated with a smaller decrease in eGFR over time.

CONCLUSION

In this large institutional cohort, oncological outcomes of renal cell carcinoma treated with SBRT were favourable and a longitudinal decline in renal function in the ipsilateral kidney and compensatory increase in the contralateral kidney were observed. Clinical and dosimetric factors were significantly associated with oncological and renal function outcomes.

[Retrospective analysis for 424 330 first-line screening results of non-invasive prenatal testing in Hebei province]

Objective: To evaluate the effect of noninvasive prenatal testing (NIPT) as first-line screening in fetal chromosome aneuploidy screening practice, and to provide evidence for the prevention and control strategy of birth defects. Methods: Since July 2019, Hebei province had carried out the NIPT project providing first-line screening for eligible pregnant women in the area (except for those who were not applicable). Pregnant women with high risk received genetic counseling, prenatal diagnosis and intervention guidance. Low risk and false-positive ones received continuous detection and moved to prenatal diagnosis center for counseling and diagnosis if abnormities were discovered. All pregnant women were followed up to learn about pregnancy outcomes and newborn health status. Detection results and clinical data of pregnant women participating the NIPT project from July 2019 to July 2020 were collected. The detection results and effect of NIPT were analyzed. Results: (1) Basic information of the screened population: A total of 424 330 pregnant women were screened, and 423 596 were successfully detected, with a success rate of 99.83% (423 596/424 330). The age of pregnant women was (28.8±4.5) years old; the gestational age of screening was (16.6±2.3) weeks; the proportion of advanced-age pregnant women (≥35 years old) was 10.18% (43 132/423 596); in vitro fertilization-embryo transfer (IVF-ET) rate was 1.58% (6 713/423 596); the twin rate was 1.38% (5 849/423 596); the proportion of primipara was 34.23% (144 977/423 596). (2) Screening results and detection performance: totally, 325, 73 and 20 pregnant women were diagnosed with trisomy 21, 18 and 13; the sensitivity were 99.39%, 100.00% and 100.00%; the specificity were 99.98%, 99.99% and 99.98%; the positive predictive value were 75.76%, 68.87% and 21.51%, respectively. Besides, 249 190 pregnant women were received supplementary reports as well, and 255, 10 and 9 were confirmed for sex chromosome aneuploidy, other autosomal aneuploidy and deletion/duplication syndrome; the positive predictive value were 37.78%, 6.06% and 32.14%, respectively. The sensitivity of NIPT for target trisomy (trisomy 21, 18 and 13) screening in advanced-age, IVF-ET and twin pregnant women were 99.29%, 100.00% and 90.00%, respectively; the specificity were 99.93% for all; the positive predictive value were 82.25%, 61.54% and 69.23%, respectively. Conclusions: NIPT has a significant effect and good performance in the first-line screening of fetal chromosome aneuploidy in the whole population, which might provide reference for the improvement of birth defect prevention and control strategy.

5-year outcomes after stereotactic ablative body radiotherapy for primary renal cell carcinoma: an individual patient data meta-analysis from IROCK (the International Radiosurgery Consortium of the Kidney)

BACKGROUND

Stereotactic ablative body radiotherapy (SABR) is a non-invasive treatment option for primary renal cell carcinoma, for which long-term data are awaited. The primary aim of this study was to report on long-term efficacy and safety of SABR for localised renal cell carcinoma.

METHODS

This study was an individual patient data meta-analysis, for which patients undergoing SABR for primary renal cell carcinoma across 12 institutions in five countries (Australia, Canada, Germany, Japan, and the USA) were eligible. Eligible patients had at least 2 years of follow-up, were aged 18 years or older, had any performance status, and had no previous local therapy. Patients with metastatic renal cell carcinoma or upper-tract urothelial carcinoma were excluded. SABR was delivered as a single or multiple fractions of greater than 5 Gy. The primary endpoint was investigator-assessed local failure per the Response Evaluation Criteria in Solid Tumours version 1.1, and was evaluated using cumulative incidence functions.

FINDINGS

190 patients received SABR between March 23, 2007, and Sept 20, 2018. Single-fraction SABR was delivered in 81 (43%) patients and multifraction SABR was delivered in 109 (57%) patients. Median follow-up was 5·0 years (IQR 3·4-6·8). 139 (73%) patients were men, and 51 (27%) were women. Median age was 73·6 years (IQR 66·2-82·0). Median tumour diameter was 4·0 cm (IQR 2·8-4·9). 96 (75%) of 128 patients with available operability details were deemed inoperable by the referring urologist. 56 (29%) of 190 patients had a solitary kidney. Median baseline estimated glomerular filtration rate (eGFR) was 60·0 mL/min per 1·73 m2 (IQR 42·0-76·0) and decreased by 14·2 mL/min per 1·73 m2 (IQR 5·4-22·5) by 5 years post-SABR. Seven (4%) patients required dialysis post-SABR. The cumulative incidence of local failure at 5 years was 5·5% (95% CI 2·8-9·5) overall, with single-fraction SABR yielding fewer local failures than multifraction (Gray's p=0·020). There were no grade 3 toxic effects or treatment-related deaths. One (1%) patient developed an acute grade 4 duodenal ulcer and late grade 4 gastritis.

INTERPRETATION

SABR is effective and safe in the long term for patients with primary renal cell carcinoma. Single-fraction SABR might yield less local failure than multifraction, but further evidence from randomised trials is needed to elucidate optimal treatment schedules. These mature data lend further support for renal SABR as a treatment option for patients unwilling or unfit to undergo surgery.

FUNDING

None.