The Metastatic Risk of Renal Cell Carcinoma by Primary Tumor Size and Subtype.

Background: Current data on the association between tumor size, subtype, and metastases, and thresholds for intervention, for renal cell carcinoma (RCC), are largely based on single-center nephrectomy registries that may under-represent those presenting with metastatic disease. Objective: We sought to assess tumor size and histologic subtype in relation to metastatic status at presentation for patients with RCC. Design setting and participants: Using Surveillance, Epidemiology and End Results cancer registry data, we identified patients with a diagnosis of RCC made between 2004 and 2019, and a known size of primary tumor. We used nodal and metastatic TNM staging to assess metastatic disease at presentation. Outcome measurements and statistical analysis: We report the proportion of metastatic disease across varying tumor sizes for clear cell (ccRCC), papillary (pRCC), and chromophobe (chRCC) RCC. We also examine sarcomatoid RCC and RCC with sarcomatoid features (sarcRCC). Logistic regression models were used to model the likelihood of metastatic disease for each histologic subtype. Results and limitations: Of 181 096 RCC patients included, 23 829 had metastatic disease. For any RCC, metastatic rates of 3.6%, 13.1%, 30.3%, and 45.1% were observed for tumors ≤4, 4-≤7, 7-≤10, and >10 cm, respectively. Metastatic rates of chRCC were low at even large sizes, 11.0% at >10 cm. In contrast, sarcRCC had high metastatic rates at all sizes, 27.1% at ≤4 cm. Metastatic rates for ccRCC and pRCC increased steadily above 3 cm. For any RCC and each evaluated subtype, tumor size was found to be associated with metastatic disease on logistic regression (p < 0.001). Conclusions: The likelihood of a renal mass being metastatic varies greatly with both its subtype and size. We report higher likelihoods of metastatic disease across tumor sizes compared with what has been reported previously. These results may help clinicians pick appropriate thresholds for intervention and candidates for active surveillance. Patient summary: We find that the metastatic probability of renal cell carcinoma varies greatly with subtype and increases with tumor size.

The Risks of Stone Diagnosis and Stone Removal Procedure After Different Bariatric Surgeries.

Introduction: Nephrolithiasis is common after malabsorptive bariatric surgery; however, the comparative risk of stone formation after different bariatric surgeries remains unclear. We seek to compare the risk of stone diagnosis and stone procedure after gastric banding (GB), sleeve gastrectomy (SG), short-limb Roux-en-Y (SLRY), long-limb Roux-en-Y (LLRY), and biliopancreatic diversion with duodenal switch (BPDDS). Patients and Methods: Using an administrative database, we retrospectively identified 116,304 patients in the United States, who received bariatric surgery between 2007 and 2014, did not have a known kidney stone diagnosis before surgery, and were enrolled in the database for at least 1 year before and after their bariatric surgery. We used diagnosis and procedural codes to identify comorbidities and events of interest. Our primary analysis was performed with extended Cox proportional hazards models using time to stone diagnosis and time to stone procedure as outcomes. Results: The adjusted hazard ratio of new stone diagnosis from 1 to 36 months, compared to GB, was 4.54 for BPDDS (95% confidence interval [CI] 3.66-5.62), 2.12 for LLRY (95% CI 1.74-2.58), 2.15 for SLRY (95% CI 2.02-2.29), and 1.35 for SG (95% CI 1.25-1.46). Similar results were observed for risk of stone diagnosis from 36 to 60 months, and for risk of stone removal procedure. Male sex was associated with an overall 1.63-fold increased risk of new stone diagnosis (95% CI 1.55-1.72). Conclusions: BPDDS was associated with a greater risk of stone diagnosis and stone procedures than SLRY and LLRY, which were associated with a greater risk than restrictive procedures. Nephrolithiasis is more common after more malabsorptive bariatric surgeries, with a much greater risk observed after BPDDS and for male patients.

Effect of Subject-Specific Vertebral Position and Head and Neck Size on Calculation of Spine Musculoskeletal Moments.

Spine musculoskeletal models used to estimate loads and displacements require many simplifying assumptions. We examined how assumptions about subject size and vertebral positions can affect the model outcomes. Head and neck models were developed to represent 30 subjects (15 males and 15 females) in neutral posture and in forward head postures adopted while using tablet computers. We examined the effects of (1) subject size-specific parameters for head mass and muscle strength; and (2) vertebral positions obtained either directly from X-ray or estimated from photographs. The outcome metrics were maximum neck extensor muscle moment, gravitational moment of the head, and gravitational demand, the ratio between gravitational moment and maximum muscle moment. The estimates of maximum muscle moment, gravitational moment and gravitational demand were significantly different when models included subject-specific vertebral positions. Outcome metrics of models that included subject-specific head and neck size were not significantly different from generic models on average, but they had significant sex differences. This work suggests that developing models from X-rays rather than photographs has a large effect on model predictions. Moreover, size-specific model parameters may be important to evaluate sex differences in neck musculoskeletal disorders.

Cognitive Versus Software Fusion for MRI-targeted Biopsy: Experience Before and After Implementation of Fusion.

OBJECTIVE: To compare the diagnostic performance of the 2 most common approaches of magnetic resonance imaging targeted biopsy (TB)-cognitive registration targeted biopsy (COG-TB) and software fusion targeted biopsy (FUS-TB)-we assessed our institutional experience with both methods. TB has emerged to complement systematic template biopsy (SB) in prostate cancer (PCa) diagnosis; however, which magnetic resonance imaging targeting methodology is diagnostically better remains unclear. MATERIALS AND METHODS: A total of 510 patients underwent TB at our institution before and after the adoption of fusion software with the UroNav platform (Invivo Corporation, Gainsville, FL). All patients had concurrent 12-core SB. We compared rates of clinically significant PCa detection, and rates of upstaging and missed diagnosis in reference to SB among patients who received COG-TB and patients who received FUS-TB. We also compared both COG-TB and FUS-TB results to their paired SB results. RESULTS: The rates of upstaging or missing clinically significant PCa with FUS-TB (in reference to SB) was not significantly different from COG-TB (P = 0.172), nor was the risk of missing clinically significant PCa different between FUS-TB vs COG-TB on logistic regression ( Odds ratio = 0.55, P = 0.106). No significant difference in biopsy outcomes was observed between FUS-TB and COG-TB (P = 0.171). We did find significant differences between FUS-TB and SB and between COG-TB and SB, with SB finding more clinically insignificant PCa (P < 0.001 and P = 0.04). CONCLUSION: In our institutional experience, no significant difference was observed between the diagnostic ability of COG-TB vs FUS-TB for detecting clinically significant PCa. Greater evidence demonstrating an advantage of FUS-TB over COG-TB would be required for clear recommendations in favor of FUS-TB.

Development and Validity of a Silicone Renal Tumor Model for Robotic Partial Nephrectomy Training.

OBJECTIVE: To provide a training tool to address the technical challenges of robot-assisted laparoscopic partial nephrectomy, we created silicone renal tumor models using 3-dimensional printed molds of a patient's kidney with a mass. In this study, we assessed the face, content, and construct validity of these models. MATERIALS AND METHODS: Surgeons of different training levels completed 4 simulations on silicone renal tumor models. Participants were surveyed on the usefulness and realism of the model as a training tool. Performance was measured using operation-specific metrics, self-reported operative demands (NASA Task Load Index [NASA TLX]), and blinded expert assessment (Global Evaluative Assessment of Robotic Surgeons [GEARS]). RESULTS: Twenty-four participants included attending urologists, endourology fellows, urology residents, and medical students. Post-training surveys of expert participants yielded mean results of 79.2 on the realism of the model's overall feel and 90.2 on the model's overall usefulness for training. Renal artery clamp times and GEARS scores were significantly better in surgeons further in training (P ≤.005 and P ≤.025). Renal artery clamp times, preserved renal parenchyma, positive margins, NASA TLX, and GEARS scores were all found to improve across trials (P <.001, P = .025, P = .024, P ≤.020, and P ≤.006, respectively). CONCLUSION: Face, content, and construct validity were demonstrated in the use of a silicone renal tumor model in a cohort of surgeons of different training levels. Expert participants deemed the model useful and realistic. Surgeons of higher training levels performed better than less experienced surgeons in various study metrics, and improvements within individuals were observed over sequential trials. Future studies should aim to assess model predictive validity, namely, the association between model performance improvements and improvements in live surgery.

Gravitational demand on the neck musculature during tablet computer use.

Tablet computer use requires substantial head and neck flexion, which is a risk factor for neck pain. The goal of this study was to evaluate the biomechanics of the head-neck system during seated tablet computer use under a variety of conditions. A physiologically relevant variable, gravitational demand (the ratio of gravitational moment due to the weight of the head to maximal muscle moment capacity), was estimated using a musculoskeletal model incorporating subject-specific size and intervertebral postures from radiographs. Gravitational demand in postures adopted during tablet computer use was 3-5 times that of the neutral posture, with the lowest demand when the tablet was in a high propped position. Moreover, the estimated gravitational demand could be correlated to head and neck postural measures (0.48 < R(2) < 0.64, p < 0.001). These findings provide quantitative data about mechanical requirements on the neck musculature during tablet computer use and are important for developing ergonomics guidelines. Practitioner Summary: Flexed head and neck postures occur during tablet computer use and are implicated in neck pain. The mechanical demand on the neck muscles was estimated to increase 3-5 times during seated tablet computer use versus seated neutral posture, with the lowest demand in a high propped tablet position but few differences in other conditions.