PMID- 35293234 OWN - NLM STAT- MEDLINE DCOM- 20220726 LR - 20220912 IS - 1546-3141 (Electronic) IS - 0361-803X (Linking) VI - 219 IP - 2 DP - 2022 Aug TI - Growth Kinetics and Progression Rate of Bosniak Classification Version 2019 Class III and IV Cystic Renal Masses on Imaging Surveillance. PG - 244-253 LID - 10.2214/AJR.22.27400 [doi] AB - BACKGROUND. Active surveillance is increasingly used as first-line management for localized renal masses. Triggers for intervention primarily reflect growth kinetics, which have been poorly investigated for cystic masses defined by the Bosniak classification version 2019 (v2019). OBJECTIVE. The purpose of this study was to determine growth kinetics and incidence rates of progression of class III and IV cystic renal masses, as defined by the Bosniak classification v2019. METHODS. This retrospective study included 105 patients (68 men, 37 women; median age, 67 years) with 112 Bosniak v2019 class III or IV cystic renal masses on baseline renal mass protocol CT or MRI examinations performed from January 2005 to September 2021. Mass dimensions were measured. Progression was defined as any of the following: linear growth rate (LGR) of 5 mm/y or greater (representing the clinical guideline threshold for intervention), volume doubling time less than 1 year, T category increase, or N1 or M1 disease. Class III and IV masses were compared. Time to progression was estimated using Kaplan-Meier curve analysis. RESULTS. At baseline, 58 masses were class III and 54 were class IV. Median follow-up was 403 days. Median LGR for class III masses was 0.0 mm/y (interquartile range [IQR], -1.3 to 1.8 mm/y) and for class IV masses was 2.3 mm/y (IQR, 0.0-5.7 mm/y) (p < .001). LGR was at least 5 mm/y in four (7%) class III masses and 15 (28%) class IV masses (p = .005). Two patients, both with class IV masses, developed distant metastases. Incidence rate of progression for class III masses was 11.0 (95% CI, 4.5-22.8) and for class IV masses 73.6 (95% CI, 47.8-108.7) per 100,000 person-days of follow-up. Median time to progression was undefined for class III masses given the small number of progression events and 710 days for class IV masses. Hazard ratio of progression for class IV relative to class III masses was 5.1 (95% CI, 2.5-10.8; p < .001). CONCLUSION. During active surveillance of cystic masses evaluated using the Bosniak classification v2019, class IV masses grew faster and were more likely to progress than class III masses. CLINICAL IMPACT. In comparison with current active surveillance guidelines that treat class III and IV masses similarly, future iterations may incorporate relatively more intensive surveillance for class IV masses. FAU - Tse, Justin R AU - Tse JR AD - Department of Radiology, Stanford University School of Medicine, 300 Pasteur Dr, Rm H-1307, Stanford, CA 94305. FAU - Shen, Luyao AU - Shen L AD - Department of Radiology, Stanford University School of Medicine, 300 Pasteur Dr, Rm H-1307, Stanford, CA 94305. FAU - Shen, Jody AU - Shen J AD - Department of Radiology, Stanford University School of Medicine, 300 Pasteur Dr, Rm H-1307, Stanford, CA 94305. FAU - Yoon, Luke AU - Yoon L AD - Department of Radiology, Stanford University School of Medicine, 300 Pasteur Dr, Rm H-1307, Stanford, CA 94305. FAU - Chung, Benjamin I AU - Chung BI AD - Department of Urology, Stanford University School of Medicine, Palo Alto, CA. FAU - Kamaya, Aya AU - Kamaya A AD - Department of Radiology, Stanford University School of Medicine, 300 Pasteur Dr, Rm H-1307, Stanford, CA 94305. LA - eng PT - Journal Article DEP - 20220316 PL - United States TA - AJR Am J Roentgenol JT - AJR. American journal of roentgenology JID - 7708173 SB - IM CIN - AJR Am J Roentgenol. 2022 Apr 27;:. PMID: 35475396 MH - Aged MH - Female MH - Humans MH - Kidney/pathology MH - *Kidney Diseases, Cystic/diagnostic imaging/pathology MH - *Kidney Neoplasms/diagnostic imaging/pathology MH - Kinetics MH - Male MH - Retrospective Studies MH - Tomography, X-Ray Computed/methods OTO - NOTNLM OT - Bosniak classification OT - cystic renal mass OT - growth kinetics OT - linear growth rate EDAT- 2022/03/17 06:00 MHDA- 2022/07/27 06:00 CRDT- 2022/03/16 08:43 PHST- 2022/03/17 06:00 [pubmed] PHST- 2022/07/27 06:00 [medline] PHST- 2022/03/16 08:43 [entrez] AID - 10.2214/AJR.22.27400 [doi] PST - ppublish SO - AJR Am J Roentgenol. 2022 Aug;219(2):244-253. doi: 10.2214/AJR.22.27400. Epub 2022 Mar 16.