Grant: Project Grant

Background: One in three patients over 60 years old will be diagnosed with a renal cyst following abdominal imaging. Traditionally, experts have recommended that complex cystic lesions (also known as Bosniak III - IV cysts) should be surgically removed, but recent evidences suggest that many are benign and that if malignant, most have low-metastatic risk. Given that many patients may not require surgery due to the excellent prognosis, alternative management should be studied. Thus, active surveillance which involves close follow-up of a patient's condition without treatment unless its condition changes, was proposed as a tradeoff option to surgery. Objectives: The goal of this multicenter project is to conduct a prospective study with a 5-year follow-up to confirm the oncologic outcomes of active surveillance in the management of complex cysts. The main objectives are: 1) to compare the 5-year cancer specific survival between cysts managed by surgery and active surveillance; 2) evaluate disease progression; and 3) evaluate patient's well-being according to each management strategy. Description: Participants (220 under active surveillance and 110 undergoing surgery) will be selected on the basis of age (over 18y), life expectancy (over 5y), diagnosis (Bosniak III and IV) and treatment choice. They will be followed with semi-annual and annual visits. Visits will serve to evaluate vital status and quality of life scores. Patients on active surveillance will also be assessed for cyst progression and will be offered surgery if progression is observed. This study, conducted in 6 large-volume Canadian centers, will be led by medical/scientific experts and patient advocates. Relevance: Validating the safety of active surveillance of complex renal cysts will be determinant in reducing overtreatment, sparing thousands of patients from unnecessary treatment, reducing the risk associated to surgery and potentially saving costs to the healthcare system.