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Automated Upper Tract Urothelial Carcinoma Tumor Segmentation During Ureteroscopy Using Computer Vision Techniques - Beyond the Abstract

The gold standard treatment for upper tract urothelial carcinoma (UTUC) is radical nephroureterectomy. However, removal of the kidney and ureter decreases overall kidney function (by leaving only one kidney), often resulting in chronic kidney disease or renal failure, which decreases quality of life and increases morbidity and mortality in many patients.1,2 Due to these severe negative consequences, endoscopic management is often preferred by patients.

By specifically treating just the tumors via local laser ablation, healthy renal tissue can be spared, and patients avoid the morbidity associated with extirpative surgery.3 Endoscopic treatment is indicated for 50% of UTUC patients who present with low-risk or (select) non-invasive high-risk tumors, and the incidence of these cases is increasing throughout the world due to improvements in diagnostics and imaging.4-7 In these cases, endoscopic management of UTUC provides for high renal preservation (75%) and cancer survival rates (90%) even in the long term.8 This is particularly impactful to the large group of patients with underlying renal dysfunction from common diseases like diabetes and hypertension. These patients are at high risk for renal failure or dialysis, which are detrimental to quality of life and costly.

Even with its benefits, however, endoscopic treatment of UTUC tumors is underutilized. Most patients who are candidates for endoscopic management nevertheless undergo nephroureterectomy after diagnosis.9 In fact, endoscopic management is not even attempted in most of the appropriate patients diagnosed with UTUC (e.g., 75% of low-risk patients undergo nephrouretectomy).10 This is because it is imprecise for most surgeons. The goal of endoscopic UTUC surgery is to completely visualize the collecting system to identify and examine all tumors while keeping track of their locations during surgery. This depends on the surgeon’s ability to create a mental 3D map of the endoscopic anatomy intraoperatively from preoperative 2D imaging, which is extremely difficult. Tumors can exist in any part of the renal collecting system, which has several, branched renal calyces that come together to funnel urine into the renal pelvis and ureter. This branched anatomy complicates mentally keeping track of UTUC tumors and the viewed/unviewed anatomy, increasing the cognitive workload of real-time tumor tracking throughout the kidney.11 To make matters worse, even when tumors are successfully visualized, the surgeon often cannot see well enough to accurately assess the location of tumor margins or infer pathologic grade. This is because the limited field of view (FOV) and depth of field (10mm and 6mm on average, respectively) of current scopes only provide visibility of a small part of the surgical field at any instant (total surgical field surface area ~ 3000mm2).12 FOV can also be obscured by debris and blood during tumor treatment. These issues with navigation and visibility also add to surgical time, increasing the risk of complications such as sepsis, postoperative pain, and kidney damage.13

Our study is a step toward improving tumor identification and tracking during endoscopic UTUC treatment. By enhancing endoscopic visualization during surgery, more accurate tumor ablation can be achieved improving outcomes and tumor recurrence.

Written by: Nicholas Kavoussi, MD, Assistant Professor of Urology, Vanderbilt University Medical Center, Nashville, TN

References:

  1. J. V. Dudinec, D. I. Ortiz-Melo, M. E. Lipkin, M. R. Abern, A. M. Shah, and B. A. Inman, “Advanced chronic kidney disease; A comparison between nephroureterectomy and nephron-sparing surgery for upper tract urothelial carcinoma.,” Urol. Oncol., vol. 41, no. 6, p. 295.e19-295.e25, Jun. 2023
  2. A. J. Gadzinski, W. W. Roberts, G. J. Faerber, and J. S. J. Wolf, “Long-term outcomes of nephroureterectomy versus endoscopic management for upper tract urothelial carcinoma.,” J. Urol., vol. 183, no. 6, pp. 2148–2153, Jun. 2010
  3. J. V. Dudinec, D. I. Ortiz-Melo, M. E. Lipkin, M. R. Abern, A. M. Shah, and B. A. Inman, “Advanced chronic kidney disease; A comparison between nephroureterectomy and nephron-sparing surgery for upper tract urothelial carcinoma,” presented at the Urologic Oncology: Seminars and Original Investigations, Elsevier, 2023, pp. 295-e19.
  4. F. G. Petros, “Epidemiology, clinical presentation, and evaluation of upper-tract urothelial carcinoma,” 2019, vol. 9, no. 4, pp. 1794–1798, 2019.
  5. A. Wihlborg and C. Johansen, “Incidences of kidney, pelvis, ureter, and bladder cancer in a nationwide, population-based cancer registry, Denmark, 1944-2003.,” Urology, vol. 75, no. 5, pp. 1222–1227, May 2010
  6. M. F. Eylert, L. Hounsome, J. Verne, A. Bahl, E. R. Jefferies, and R. A. Persad, “Prognosis is deteriorating for upper tract urothelial cancer: data for England 1985-2010.,” BJU Int., vol. 112, no. 2, pp. E107-113, Jul. 2013
  7. T. van Doeveren, M. van der Mark, P. J. van Leeuwen, J. L. Boormans, and K. K. H. Aben, “Rising incidence rates and unaltered survival rates for primary upper urinary tract urothelial carcinoma: a Dutch population-based study from 1993 to 2017.,” BJU Int., vol. 128, no. 3, pp. 343–351, Sep. 2021
  8. K. B. Scotland et al., “Long-term outcomes of ureteroscopic management of upper tract urothelial carcinoma.,” Urol. Oncol., vol. 38, no. 11, p. 850.e17-850.e26, Nov. 2020
  9. K. E. Fero et al., “Treatment Patterns, Outcomes, and Costs Associated With Localized Upper Tract Urothelial Carcinoma.,” JNCI Cancer Spectr., vol. 5, no. 6, Dec. 2021
  10. A. Upfill-Brown et al., “Treatment utilization and overall survival in patients receiving radical nephroureterectomy versus endoscopic management for upper tract urothelial carcinoma: evaluation of updated treatment guidelines.,” World J. Urol., vol. 37, no. 6, pp. 1157–1164, Jun. 2019
  11. A. Gallioli et al., “The Impact of Ureteroscopy following Computerized Tomography Urography in the Management of Upper Tract Urothelial Carcinoma.,” J. Urol., vol. 205, no. 2, pp. 392–399, Feb. 2021
  12. S. Proietti, L. Dragos, W. Molina, S. Doizi, G. Giusti, and O. Traxer, “Comparison of New Single-Use Digital Flexible Ureteroscope Versus Nondisposable Fiber Optic and Digital Ureteroscope in a Cadaveric Model.,” J. Endourol., vol. 30, no. 6, pp. 655–659, Jun. 2016
  13. L. B. Dragos et al., “Characteristics of current digital single-use flexible ureteroscopes versus their reusable counterparts: an in-vitro comparative analysis.,” Transl. Androl. Urol., vol. 8, no. Suppl 4, pp. S359–S370, Sep. 2019
  14. M. Baboudjian et al., “Long-Term Oncologic Outcomes of Endoscopic Management of High-Risk Upper Tract Urothelial Carcinoma: The Fundació Puigvert’s Experience.,” J. Endourol., vol. 37, no. 9, pp. 973–977, Sep. 2023
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