Renal Cysts
Incidental cysts are a common finding and 8-15% of identified cysts are complex. (2,3,4) Meta-analysis have described incidence of RCC in Bozniak IIF at 6-18%, III 51-55% and IV 89-91%. (5,6,10) Cystic RCC has better CSS than solid clear cell RCC of the same clinical stage, specifically T1b and T2. (7,8) In a retrospective study, 68 Bozniak IIF and 131 III lesions were evaluated with no metastasis. (7) Multilocular cystic RCC has an excellent prognosis despite clincial T stage (9) and RCC identified in cystic renal masses has improved cancer specific outcomes compared to solid RCC counterparts. (8) The number needed to treat to prevent metastasis may be as high as 140 for Bosniak III cysts and 40 for Bosniak IV cysts. (10) Metastatic disease is extremely reare in cystic RCC, with one retrospective study showing only one patient out of 158 cystic RCC treated with nephrectomy developing metastasis, 22 years after surgery and an overall cancer specific of 88% at 25 years. (11) Another retrospective study of 128 patients with cystic RCC treated with nephrectomy had no recurrences and no metastasis at mean follow up of 66 months. (12)
A 2018 retrospective study of 336 patients with 36% Bozniak III and 8.6% Bozniak IV showed only 1 cancer specific death at median 67.1 month follow up for a 99.7% CSS and 93.8% OS. When excluding patients with von-Hippel-Lindau syndrome, the CSS rate was 100%. Ultimately, 23 underwent radical nephrectomy, 37 underwent partial nephrectomy with 5.4% of IIF, 30% of III and 62% of IV undergoing intervention. 11% of patients were biopsied with a 34% malignancy rate. In this study the only patient with metastasis while on active surveillance had progression develop after 12 years despite an initial diagnosis of Bozniak IV. This gave the Bosniak IV group had 10.3% with metastasis and 1 RCC specific death. (1) In a systemic review of 373 patients, only 1 with Bosniak III cyst went on to metastatic disease after 8 years of surveillance and this patient was salvaged with local therapy and lung oligometastatectomy. (5)
A 2018 retrospective study of 336 patients with 36% Bozniak III and 8.6% Bozniak IV showed only 1 cancer specific death at median 67.1 month follow up for a 99.7% CSS and 93.8% OS. When excluding patients with von-Hippel-Lindau syndrome, the CSS rate was 100%. Ultimately, 23 underwent radical nephrectomy, 37 underwent partial nephrectomy with 5.4% of IIF, 30% of III and 62% of IV undergoing intervention. 11% of patients were biopsied with a 34% malignancy rate. In this study the only patient with metastasis while on active surveillance had progression develop after 12 years despite an initial diagnosis of Bozniak IV. This gave the Bosniak IV group had 10.3% with metastasis and 1 RCC specific death. (1) In a systemic review of 373 patients, only 1 with Bosniak III cyst went on to metastatic disease after 8 years of surveillance and this patient was salvaged with local therapy and lung oligometastatectomy. (5)
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- Chandrasekar, Thenappan, et al. "Natural history of complex renal cysts: clinical evidence supporting active surveillance." The Journal of urology 199.3 (2018): 633-640.
- Hitzeman, Nathan, and Erin Cotton. "Incidentalomas: initial management." American family physician 90.11 (2014).
- Harisinghani, Mukesh G., et al. "Incidence of malignancy in complex cystic renal masses (Bosniak category III): should imaging-guided biopsy precede surgery?." American Journal of Roentgenology 180.3 (2003): 755-758.
- Di Vece, Francesca, et al. "Management of incidental renal masses: time to consider contrast-enhanced ultrasonography." Ultrasound 24.1 (2016): 34-40.
- Richard, Patrick O., et al. "CUA guideline on the management of cystic renal lesions." Canadian Urological Association Journal 11.3-4 (2017): E66.
- Ljungberg, Borje, et al. "EAU guidelines on renal cell carcinoma: 2014 update." European urology 67.5 (2015): 913-924.
- Smith, Andrew D., et al. "Bosniak category IIF and III cystic renal lesions: outcomes and associations." Radiology 262.1 (2012): 152-160.
- Winters, Brian R., et al. "Cystic renal cell carcinoma carries an excellent prognosis regardless of tumor size." Urologic Oncology: Seminars and Original Investigations. Vol. 33. No. 12. Elsevier, 2015.
- Bhatt, Jaimin R., et al. "Multilocular cystic renal cell carcinoma: pathological T staging makes no difference to favorable outcomes and should be reclassified." The Journal of urology 196.5 (2016): 1350-1355.
- Schoots, Ivo G., et al. "Bosniak classification for complex renal cysts reevaluated: a systematic review." The Journal of urology 198.1 (2017): 12-21.
- Westerman, Mary E., et al. "MP55-07 LONG TERM OUTCOMES OF PATIENTS WITH CYSTIC CLEAR CELL RENAL CELL CARCINOMA." The Journal of Urology 197.4 (2017): e732-e733.
- Kashan, Mahyar, et al. "MP55-08 DIAGNOSIS, MANAGEMENT, AND CLINICAL OUTCOMES OF CYSTIC RENAL CELL CARCINOMA." The Journal of Urology 197.4 (2017): e733.