Presentation Authors: Se Young Choi, Bumjin Lim, Jae Hyeon Han, Yoon Soo Kyung, Dong Hyeon An, Hwiwoo Kim, Wonchul Lee, Han Kyu Chae, Jaehoon Lee, Wonseok Choi*, Dalsan You, In Gab Jeong, Jun Hyuk Hong, Hanjong Ahn, Choung-Soo Kim, Seoul, Korea, Republic of
Introduction: We sought to validate stage of the American Joint Committee on Cancer (AJCC) 8th edition, which eliminated pathologic T2 subclassification, comparing to AJCC 7th edition and to suggest prognostic T2 subcategory using percent tumor volume in biochemical recurrence (BCR) of prostate cancer.
Methods: A total of 1073 patients who underwent radical prostatectomy and had pathologic T2 stage were included. Exclusion criteria were neoadjuvant therapy. BCR-free survival was estimated using the Kaplan-Meier method. Cox hazard regression was used to predict BCR.
Results: Median follow-up period was 27.6 months (interquartile range 13.1â€“41.1). On Kaplan-Meier curve, T2 subcategory of AJCC 7th did not show significant difference for BCR (p=0.502). Percent tumor volume was significantly correlated with initial PSA (beta: 0.10, 95% confidence interval [CI] 0.05â€“0.15, p < 0.001) and T2 subcategory of AJCC 7th (beta: 2.35, 95% CI 1.68â€“3.02, p < 0.001). On multivariate analysis for BCR-free survival, pathologic Grade Group (2 vs 1; Hazard ratio [HR] 2.384, 95% CI 1.055â€“5.387, p=0.037, 3 vs 1; HR 4.474, 95% CI 1.958â€“10.225, p < 0.001, 4 vs 1; HR 11.816, 95% CI 4.716â€“29.602, p < 0.001, 5 vs 1; 5.283, 95% CI 1.706â€“16.359, p=0.004), surgical margin (HR 4.348, 95% CI 2.896â€“6.528, p < 0.001), and percent tumor volume (HR 1.023, 95% CI 1.005â€“1.041, p=0.013) were significant predictors. On Kaplan-Meier curve, percent tumor volume (>7.5 vs â‰¤7.5) showed significant difference for BCR-free survival (p < 0.001).
Conclusions: The T2 stage of AJCC 8th is more appropriate for BCR prediction than T2 subcategory of AJCC 7th. Percent tumor volume can classify the prognosis of BCR in pathologic T2 stage.