Salvage Robotic-assisted Laparoscopic Radical Prostatectomy: Experience with 14 Cases

Discussion

Several studies have demonstrated salvage local treatment for prostate such as SRP could lead to considerably improved BCR-free and metastasis-free survival (11, 12). Although some factors such as poorly differentiated tumor and high Gleason score, rapidly rising PSA with short doubling time, or undetectable nadir PSA have been shown to be associated with BCR, no individual factors have definitively excluded the possibility that local salvage therapy may be beneficial (13, 14). Several studies on the use of SRP after definitive radiation therapy reported that surgical complications and functional outcomes were the major concerns (4, 15). Salvage ADT may be the first consideration for patients with BCR after local treatment due to fewer comorbidities; however, despite its systemic treatment effect, it is still not a curative treatment option (16). SRP may provide the possibility of disease-free status with a 5-year BCR-free survival rate of approximately 64% and a one-year continence rate of 80% (11).

In the era of robotic surgery, the benefits of 3-dimensional vision and endowrist instruments for deep pelvic surgery have yielded excellent outcomes worldwide over the past 10 years (17). At our Institute, more than 1,200 prostatic surgeries have been carried out with excellent oncology and functional outcomes (18, 19). Maintenance of the pneumoperitoneum can reduce bleeding from the venous plexus. High resolution 3-dimensional imaging allows fine dissection, especially when developing the plane of Denonvilliers' fascia, which helps prevent rectal injury and enables maximal preservation of functional urethra. A water-tight anastomosis reduces the incidence of postoperative leakage.

The most notable difference between S-RaRP and RaRP may be the risk of severe adhesion and obscure plane after radiation therapy (20). Surgery begins from the posterior aspect of the prostate, with sharp dissection at Denonvilliers' fascia, which provides early protection of the rectum. After dropping the bladder later, the endopelvic fascia can be opened with sharp dissection and in most situations, this plane may be obliterated and hard to recognize (21). Performing dissection of bladder neck and full mobilization will improve the visualization of prostatatic apex, which may be the most adherent after radiation therapy and easily lead to rectal injury (22, 23).

Table V lists the surgical variables of S-RaRP in our series and in the literature. In our perioperative outcomes, the operation time was about 34.9 minutes and the estimated blood loss was 99.6 ml, which were similar to values reported in other studies: operative time ranged from 130 to 183 minutes and the estimated blood loss ranged from 75 to 381 ml. This indicates that despite the greater difficulty of the surgery, we were still able to achieve an acceptable operative time and limited blood loss. Rectal injury is another risk of concern, but fortunately it was not observed in our series. The only patient who suffered from rectal injury reported by Kaffenberger et al. had an unrecognized pT4 disease (23), and the overall incidence was still low. This may be due to the advantage provided by high-resolution imaging in S-RaRP. The incidence of rectal injury in SRP was more common with a prevalence rate of 0-28% (12).

Anastomosis stricture was another complication with a prevalence rate of 14.3% in our series. Radiation-induced cell apoptosis, inflammation, vascular injury, and atrophy lead to poorly-oxygenated tissue and eventual tissue scarring, which results in a greater frequency of anastomosis stricture than in normal prostate tissue (24, 25). In contrast, continence outcome with pad-free status or only one safety pad was good in our series (71.4%) and ranged from 33-80% in the literature. Potency was hard to assess as only three patients were potent before surgery. Bate et al. reported an overall continence rate of 76.9% and a potency rate of 31.5% in a series of 53 patients who underwent S-RaRP, which provided the advantage of NVB sparing (25).

In our series, we achieved a relatively low positive surgical margin rate (21.4%). Most patients who underwent salvage local treatment had more advanced disease. Greater tissue density, obscure plane, and advance tumor behavior may lead to a higher incidence of positive surgical margin, which ranged from 13 to 31.4% in the literature. Most positive surgical margins occurred at the prostattic apex with an overall rate of 78% (23). Consistent with previous studies, our findings showed that S-RaRP provided patients with the possibility of becoming disease-free, with a BCR-free survival rate of 78.5% at a mean follow-up of 32.4 months.

Although S-RaRP achieved an excellent oncology outcome and an acceptable functional outcome, it is important to note that this surgical modality should be applied on an individual basis after the patient has undergone a thorough evaluation to avoid unnecessary surgery.

In order to attain the benefits of a reduced complication rate and a better surgical outcome provided by S-RaRP, the clinician must perform patient selection according to certain criteria. Several previous studies have demonstrated a number of important prognostic variables that appear to predict oncology outcome. Kaffenberger et al. reported PSA doubling time and Gleason score at original diagnosis were two major independent risk factors for BCR (23). Yuh et al. reported that high PSA and extracapsular extension may be related to early BCR, with an estimated 3-year BCR rate of 43% (24). In summary, most patients who underwent S-RaRP had a relatively advanced disease status with potential distant metastasis and therefore patient selection is of paramount importance. Preoperative bone scan and computed tomography is crucial for detecting distal metastatic lesions to prevent unnecessary surgery.

In our single-institute experience, our findings indicate that S-RaRP was capable of achieving good oncological control with an excellent BCR free-rate, as well as satisfactory symptomatic control. Most of the patients that received radiation suffered from low urinary tract symptoms related to chronic obstruction which were resolved after surgical intervention. Although some patients suffered from incontinence, an experienced surgeon can expect to achieve excellent overall functional outcome. Our outcomes showed that S-RaRP resulted in fewer surgical complications such as low estimated blood loss and no rectal injury and thus we propose that this modality may offer suitable candidate patients the possibility of becoming cancer-free.

There were some limitations to our study. This was a retrospective investigation with a limited number of patients and thus these findings should be interpreted with caution in clinical practice. Moreover, because prostate cancer is relatively slow-growing, further long-term follow-up may be needed to further clarify the beneficial effect of S-RaRP on survival rates.