GUIDELINE EVALUATION FOR SECONDARY RENAL CELL CARCINOMA SCREENING

Purpose:

   To evaluate cost, radiation exposure, and cancer control of imaging surveillance strategies to screen for secondary renal cell carcinoma (RCC).

Methods:

   We present a Monte Carlo simulation model to assess clinical outcomes and costs of post-surgery screening for recurrent RCC.  Imaging surveillance includes abdominal imaging (ultrasound, abdominal computerized tomography (CT)) and chest imaging (chest x-ray (CXR), chest CT).  Numerical results are presented for low risk patients who have undergone partial nephrectomy to manage the primary tumor. We compare hypothetical strategies to current guidelines from four clinical organizations: American Urological Association (AUA), Canadian Urological Association (CUA), European Association of Urology (EAU), and National Comprehensive Cancer Network (NCCN).  Hypothetical strategies vary in the number of years of follow-up (3, 4, or 5 years), modalities (ultrasound and CXR, or abdominal and chest CT), and frequency of imaging (1 or 2 studies in each location per year). Costs, recurrence information, radiation exposure estimates, and modality-specific detection rates were taken from secondary sources. Model outcomes are percentage of recurrent patients diagnosed, size of the recurrent tumor at diagnosis, radiation exposure due to imaging, and cost of screening.

Results:

   CUA guidelines have the lowest average cost for recurrent patients ($435.88), the lowest average radiation exposure (22.96mSv), and the highest percentage of recurrent patients diagnosed (95%, same as EAU); however, CUA has the largest tumor size at recurrence (2.13cm).  EAU has similar cancer control outcomes to CUA with increased costs ($1297.60) and radiation (65.06mSv).  AUA and NCCN diagnose the smallest percentage of recurrent patients, primarily due to follow-up duration, though the tumor size at diagnosis is improved (1.64cm and 1.49cm, respectively).  The percentage of patients diagnosed with the hypothetical strategies varies (45.9-95.1%); longer follow up and more precise CT imaging are associated with higher rates.  Strategies with CT imaging have smaller tumor size at diagnosis, increased costs, and higher radiation exposure compared to strategies with ultrasound and CXR.  Higher numbers of imaging studies per year provide little benefit.

Conclusions:

   CUA provides a balance of a high percentage of diagnoses with low costs and radiation.  The analysis of hypothetical strategies shows that surveillance should be continued for 5 years, and a single imaging study in each location is sufficient.  Imaging modality should be chosen based on available budget and cancer control goals.