Comparison of Surgery and Active Surveillance in the Treatment of Bosniak III Renal Cysts

Summary

The incidence of renal cysts is rising due to increased abdominal imaging. Renal complicated cysts have been traditionally classified according to the Bosniak classification, which distinguishes cystic masses by specific features of walls and septa. The categories I and II are benign and class IIF most probably benign but needs a short radiological follow-up. Categories III and IV have been traditionally operated due to the increased risk of renal cell carcinoma. However, recently published studies show that approximately 50% of the operated Bosniak III cystic masses are benign, which means that half of the cases are overtreated by surgery. It has also been shown that surgical pathology of stable Bosniak IIF cysts is malignant in less than 1%, while the cysts, which are upgraded to higher Bosniak classes will show malignant surgical pathology in 85%. So far, there is lack of prospective data on active surveillance in Bosniak III cystic masses.

The aim of the study is to compare active surveillance and surgery in patients with Bosniak III renal cystic masses. Patients will be randomized in active surveillance or immediate surgical excision of a cystic mass. In the active surveillance group, patients are followed according to the study protocol for 10 years and treated with delayed surgery if the cystic mass upgrades into Bosniak IV/solid, becomes symptomatic or grows over a preclassified threshold. The primary objective is to compare surgical pathology between patients treated with immediate surgery versus delayed surgery.

According to recent retrospective data, active surveillance of Bosniak III cystic masses is reasonable and oncologically safe. Therefore a prospective randomized controlled trial is needed to get high level evidence to support a change in the treatment strategy. The study may significantly reduce unnecessary operations performed in patients with Bosniak III cystic masses.

Conditions

• Cystic Renal Disease
• Kidney Cancer
• Surgery

Interventions

PROCEDURE

Delayed surgery

Delayed surgery is performed if cystic mass radiologically upgrades into Bosniak 4 or solid mass in the active surveillance.

PROCEDURE

Immediate surgery

Partial or radical nephrectomy is performed as treatment of Bosniak 3 cystic mass

Sponsors & Collaborators

• Helsinki University Central Hospital

  lead OTHER

Principal Investigators

• Harry Nisén · Helsinki University Central Hospital

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

50 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2021-03-15

Primary Completion

2024-01-11

Completion

2036-01-11