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Follow-up imaging after nephrectomy for cancer in Canada: urologists' compliance with guidelines. An observational study.

BACKGROUND
Surgical tumour removal remains the preferred treatment for most patients with renal cell carcinoma, and many medical associations have proposed guidelines for the optimal surveillance of patients following surgery. This study evaluated the adherence of Canadian urologists to the follow-up guidelines proposed by the Canadian Urological Association (CUA) in 2009.


METHODS
The study cohort was identified from the Canadian Kidney Cancer Information System, a prospectively populated database from 15 academic institutions in 6 Canadian provinces: British Colombia, Alberta, Manitoba, Ontario, Quebec and Nova Scotia. A total of 1982 patients who underwent radical or partial nephrectomy for stage pT1-3N0M0 renal cancer between January 2011 and June 2016 were included in the cohort. Numbers of abdominal and chest imaging tests performed during the follow-up period were captured and compared with the 2009 CUA guidelines. The level of compliance was measured by means of weighted κ and Pearson correlation statistics. Multivariate logistic regression was used to evaluate factors associated with noncompliance (under- or overtesting) in the postoperative surveillance period.


RESULTS
Of the 1982 patients, 1380 had stage pT1 disease, 164 had stage pT2 disease, and 438 had stage pT3 disease. There was incongruent adherence to the CUA surveillance guidelines, with a ratio of observed to recommended tests of 0.71 and 2.27 for chest and abdominal imaging, respectively. Overall, moderate correlation between observed and recommended tests was observed, with the highest value found for abdominal imaging in the pT3 group (κ = 0.59 [95% confidence interval 0.52-0.66]). Patients who underwent radical nephrectomy and those who presented with a higher stage of the disease were less likely to receive fewer chest imaging tests than recommended, and those with stage pT2 disease, those with stage pT3 disease, those with conventional clear cell renal cell carcinoma and those with a low-risk histologic type had an increased risk of undertesting.


INTERPRETATION
In the 6 Canadian provinces, there are large differences between guidelines and clinical practice in imaging surveillance after nephrectomy for renal cell carcinoma. Better adherence to clinical guidelines could improve optimization of health care services.