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Introduction - Conflicting data exists on the role of maximum tumor diameter (MTD) as a predictor of biochemical recurrence (BCR) in men with organ confined prostate cancer with negative surgical margins after radical prostatectomy (RP). We evaluate MTD in a large contemporary patient cohort.
Methods - RP from a single-institution database were studied (2000-2012). Inclusion criteria: organ-confined pathology (pT2a-T3a), negative surgical margins, no adjuvant therapy, and minimum 12-month follow-up. The largest tumor diameter (MTD) of the largest tumor focus was prospectively measured. Chi-squared test and odds ratios comparing MTD and BCR for tumors ≤1 cm and > 1 cm in each of the following categories were calculated: overall group, Gleason 3+3, 3+4, 4+3, and Gleason score 8,9 and 10.
Results - Median follow-up was 58 months. BCR and mean MTD overall was 73/1048(6.9%) and 1.5cm, in 3+3 9/337(2.6%) and 1.1cm, in 3+4 30/482(6.2%) and 1.6cm, in 4+3 25/185(13.5%) and 1.6cm, and in the 8, 9, 10 group 9/45(20%) and 1.3cm. In the overall group, MTD > 1 cm showed a significant increase in BCR compared to ≤ 1 cm (p< 0.04). Odds ratio trends were largest in the overall, 3+3 and 3+4 groups (but not statistically significant), though this trend was not found in the higher grade groups.
Conclusions - Prostate cancers > 1 cm are associated with increased risk of BCR. This effect appears to be most pronounced with low grade tumors, as predominantly high grade tumors have increased risk for BCR even at MTD ≤ 1 cm.