Prostate Cancer in Patients With High Prostate-Specific Antigen Levels but Otherwise Very-Low-Risk Disease Behaves Like Prostate Cancer in High-Risk Patients

Abstract

Introduction: Rarely, patients with prostate cancer present with prostate-specific antigen (PSA) scores > 20 ng/mL but with otherwise very-low-risk disease. Oncologists have debated whether the malignancies in these patients behave more comparably to low-risk or high-risk disease. Our objective was to elucidate the behavior of these malignancies.

Materials and methods: A retrospective review was conducted of prostate cancer patients treated with radiation from 2000 to 2013. The inclusion criteria for very-low-risk disease included stage T1a-T1c, Gleason score ≤ 6, ≤ 3 positive cores, ≤ 50% involvement of any core, and PSA level < 10 ng/mL. The divergent-risk group met all the same criteria but had a PSA score of 20 to 80 ng/mL. The high-grade, low-volume group consisted of patients with stage T1c-T2a, PSA level < 20 ng/mL, Gleason score of 4+4, and < 4 positive cores. Treatment failure was defined as a PSA nadir plus 2 ng/mL.

Results: A total of 18, 60, and 19 patients were in the divergent, low-risk, and high-grade groups, respectively. Biochemical progression-free survival at 5 years was 71.3% for the divergent group, 68.8% for the high-grade group, and 98.3% for the low-risk group. The biochemical failure rate for the divergent group differed significantly from the low-risk group (P = .021), and that for the low-risk group was significantly different from that of the high-grade group (P = .025). However, the divergent group did not appear different from the high-grade group (P = .53).

Conclusion: The results of our study have shown that the disease prognosis for the divergent-risk group is worse than that for the very-low-risk disease group and does not appear to be different from that for the low-volume, high-grade disease group. Oncologists should be aware that the outcomes for divergent patients are similarly poor to their low-volume, classically high-risk counterparts.

Keywords: Divergent risk; High PSA; High-risk disease; Low-volume disease; Very-low-risk prostate cancer.