A 69-Year-Old Man Underwent a Radical Prostatectomy Ii Years Ago

A 69-year-old man underwent a radical prostatectomy ii years ago. His serum prostate-specific antigen (PSA) level was 7.1 ng/mL, clinical stage was Tic (clinically organ-confined and detected by screening PSA blood test only) , and his Gleason score was 5. His PSA level became detectable 4 years ago. Over the past 3 years, his PSA values have been 1.4 ng/mL, 1 .8 ng/mL, and 2.2 ng/mL. He remains asymptomatic, and a recent bone scan revealed only degenerative disease. The patients risk for rapid metastasis is low for which of the following reasons?

A) He was initially treated by radical prostatectomy.
B) His PSA level became undetectable.
C) He has had a slow, prolonged rise in his PSA.
D) He is almost 70 years old.