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Margins in Prostate Cancer Surgery Methodology

Positive Margins Following Radical (or Total) Prostatectomy
Short description of Indicator Percent of pT2 and pT3 radical (or total) prostatectomy pathology reports where positive margin was reported by pT stage​
Rationale for measurement

One of the main goals of radical (or total) prostatectomy is the complete eradication of the cancer-containing organ and negative surgical margins. However, clinical expert feedback has previously indicated there is practice variation in the surgical management of prostate cancer patients, leading to high positive margin rates in Ontario. Positive surgical margins are associated with higher rates of cancer recurrence.

The intent of this indicator is to monitor the quality of prostate surgeries by measuring the positive margin rate following radical (or total) prostatectomy. Margin status is a good indicator of the quality of surgery and pathology because it helps predict how the disease will progress and how likely it is to recur.

Evidence/references for rationale Recommendations for improving the quality of prostate cancer surgery and pathological assessment in radical prostatectomy: A guideline released in 2008 and updated in 2017.
Calculations for the indicator % Reports with Positive Margins (pT2) = (Number of pT2 radical [or total] prostatectomy reports with involved margins)/(Number of pT2 radical [or total] prostatectomy reports)

% Reports with Positive Margins (pT3) = (Number of pT3 radical [or total] prostatectomy reports with involved margins)/(Number of pT3 radical [or total] prostatectomy reports)
Standardized Rate Calculation N/A
Unit Percentage (%)
Data sources Pathology Data Mart
Time Frame CY 2013-2017​​
Geographic Scale Provincial​
Denominator description Patients with pT2 or pT3 disease that had a radical (or total) prostatectomy
Numerator description Patients with positive margins: number of pT2 or pT3 reports with involved margins​
Considerations N/A
Data availability & limitations Excludes:
  • All non-cancer cases
  • Reports not received in discrete data field format (i.e., narrative reports)
  • ICD-O-3 behaviors of 0 (benign), 1 (borderline), 6 (metastatic), and 2 (in situ)
  • Consults
  • All report types other than surgical pathology reports (i.e., biopsies are excluded)
  • Reports from private labs and pediatric hospitals
  • Reports with pT4 primary tumour or primary tumour not identified
  • Reports where margin involvement by invasive carcinoma is not identified or margin involement cannot be accessed​