Post-RP Treatment Options
Within a few weeks after RP (but not after primary RT), PSA should fall below detection limits (biochemically no evidence of disease; bNED), since its serum half-life is only 2–3 days. While minimum detectable concentrations are approximately 1 pg/ml or lower,[25,26] a PSA of 0.2 ng/ml is now a widely accepted threshold to state biochemical relapse if confirmed in a second measurement.[19,27,28,201] As rising PSA values precede metastatic progression and tumor-specific death by several years, they serve as a surrogate marker of recurrence after primary therapy. However, a positive detection after intended radical extirpation may result from cancer regrowth (including regional lymph nodes), but also from distant metastases or from residual normal prostate tissue. In these latter cases, local salvage treatment is futile. Moreover, patients with (slowly) rising PSA values do not always develop distant metastases. Although there is no fixed relation between PSA and the risk of (bone) metastasis, bone scintigrams at a PSA <7 ng/ml are rarely positive, while at >20 ng/ml they are quite likely to be positive.[30,31]
However, even patients with undetectable PSA stand to profit from adjuvant treatment;[32,33] although the potential advantage from adjuvant RT (ART) compared with salvage RT (SRT) has been disputed even for R1 resection. ART evidently leads to overtreatment, which could be avoided by SRT. But then, careful post-RP surveillance is essential for a timely therapy (with PSA ≤0.5 ng/ml), which improves bNED by 10–20% compared with delayed SRT.[19,35,36]
General post-RP adjuvant hormone therapy (HT) has been discouraged by guidelines for local disease but it can improve survival for high-risk profile locally advanced (node-positive) or systemic disease.[37–39,201] While surgical specimens give clear information on node status, there is currently no conclusive evidence for reliable imaging to this end. Data on HT in response to biochemically recurrent PC are comparably scarce. Side effects, including psychological aspects, must be considered with respect to the different hormone-suppressive approaches: orchidectomy; steroidal; or nonsteroidal medication.[42–44] A large randomized study is underway; RADICALS aims to recruit >4000 patients and address both the comparison of ART versus SRT and the question of additional hormone treatment (using a gonadotropin-releasing hormone analog) and its appropriate timing after RP. In addition, a French study with a planned enrollment of 718 patients will compare ART versus SRT, both combined with a gonadotropin-releasing hormone analog.
Future Oncol. 2013;9(5):669-679. © 2013 Future Medicine Ltd.