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This article reviews the current data on KTP laser vaporization and HoLEP, emphasizing outcomes compared with those of TURP and OP, to determine whether a new gold standard exists for the surgical management of BPH/LUTS.
Photoselective vaporization of the prostate (PVP) is generated by passing a neodymium:yttrium-aluminum-garnet laser through a KTP crystal to double the frequency and produce a 532-nm wavelength. The laser energy is delivered by a side-firing glass fiber through a 27F continuous flow resectoscope using saline. Initial prostate vaporization used 60-watt KTP lasers, but due to slower vaporization times, newer 80-watt KTP and 120-watt lithium triborate laser systems have been developed. Even more recently, a 180-watt system has been introduced.
Comparing outcomes of PVP with TURP is difficult, as the data from PVP (80-watt KTP and 120-watt lithium triborate lasers) are relatively young. In a randomized clinical trial (RCT) comparing KTP with TURP, Bouchier-Hayes et al demonstrated an increase in Qmax (from 8.5 cc/sec to 20.6 cc/sec) and a decrease in International Prostate Symptom Score (IPSS) (from 25.7 to 12), which was comparable to the control TURP group (J Endourol 2006; 20:580-5). In another prospective randomized trial by Horasanli et al, a significant difference in Qmax, IPSS, and post-void residual volume (PVR) values were observed and were in favor of the TURP group (Urology 2008; 71:247-51). In both studies, the PVP group demonstrated a shorter length of catheterization (LOC) and a shorter length of stay (LOS) compared to the TURP group (J Endourol 2006; 20:580-5; Urology 2008; 71:247-51).
Unfortunately, the longest follow-up comparing PVP to TURP is only 2 years, and therefore the durability of these results cannot be ascertained at this time. There is one RCT comparing PVP to OP for prostate glands larger than 80 grams. The follow-up for this study was 12 months. In this study, Alivizatos et al demonstrated a similar improvement in IPSS in both groups at 12 months; however, the IPSS quality of life score was better in the OP group at 12 months. As well, Qmax and PVR improvements were also comparable in the two groups. Finally, the transfusion rate was significantly lower in the PVP group (Eur Urol 2008; 54:427-37).
PVP has yielded promising short-term data; however, it is also associated with a few drawbacks. First, it requires the use of at least one new laser fiber for each prostate vaporization.
Second, there is a substantial risk of BPH recurrence. The re-treatment rate ranged significantly from 6.7% at 24 months in one study (BJU Int 2008; 102:1432-8; discussion 1438-9) to 17.9% at 6 months in another study examining treatment of larger glands (≥70 cc) (Urology 2008; 71:247-51). Finally, this procedure does not allow for tissue specimen retrieval and, therefore, pathologic analysis cannot be performed.
In summary, PVP shows short-term data that are comparable to TURP for smaller and medium-sized glands and comparable to OP for larger glands. As well, PVP has shorter LOC, shorter LOS, and lower rates of transfusion. The problem with PVP is the lack of long-term data demonstrating the durability of the short-term results. One might ask why this is. In a systemic review and meta-analysis of minimally invasive procedures, Burke et al found six unpublished RCT data sets from abstracts dating back to 2002-'05. They concluded that this suggests a potential publication bias (Urology 2010; 75:1015-22).