Oncologic outcomes similar for robotic, open radical prostatectomy, according to study

September 1, 2012

In the hands of high-volume surgeons, there is no evidence to suggest that robot-assisted laparoscopic prostatectomy results in worse oncologic outcomes then open radical prostatectomy, even in patients with high-risk cancer.

Key Points

Atlanta-In the hands of high-volume surgeons, there is no evidence to suggest that robot-assisted laparoscopic prostatectomy results in worse oncologic outcomes then open radical prostatectomy, even in patients with high-risk cancer, according to a retrospective study of patients operated on at a large tertiary care center.

The equivalent outcomes could be attributed to "adherence to the oncologic principles of the operation, which included a thorough pelvic lymph node dissection and a focus on surgical techniques to reduce positive margins," said lead author Jonathan Silberstein, MD, a urologic oncology fellow at Memorial Sloan-Kettering Cancer Center, New York. He presented the data at the AUA annual meeting in Atlanta.

Using a case-mixed adjusted comparison, early oncologic outcomes were compared between a group of 961 patients who underwent open prostatectomy and 493 who underwent robotic RP performed by four high-volume surgeons at Memorial Sloan-Kettering between 2007 and 2010. Patients were excluded if they underwent surgery using the surgeon's non-dominant technique, if they underwent salvage surgery, or if they received adjuvant therapy.

Confirming the high-risk features, about half of the patients in each group had clinical Gleason 7 disease and more than one-third in each group had extracapsular extension. Ten percent in the open group and 8% in the robotic group had positive lymph node invasion. Margins were found to be positive in 15% of each treatment group.

The pelvic lymph node dissection was performed using a template that included, at a minimum, the external, obturator, and internal nodal packets. Pelvic lymph node dissection was performed in 94% of patients, as it was omitted in some patients with NCCN low-risk disease. Complete or partial nerve sparing was performed in all but 2% of the patients.

Biochemical recurrence was defined as a PSA level ≥1.0 ng/mL or any measurable PSA followed by further therapy for cancer.

Postoperatively, 10% had Gleason ≥8 disease (11% who underwent open RP vs. 8% who underwent the robotic procedure) and 15% had positive surgical margins.

Difference in recurrence not significant

Using a multivariable Cox regression model, the hazard ratio for biochemical recurrence for robotic compared with open RP (adjusting for preoperative risk) was 0.88, which was not significant (p=.6). Using NCCN risk as the covariate in a Cox model yielded virtually identical results (hazard ratio: 0.74; p=.2).

The overall adjusted 2-year probability of recurrence was 4.1% for open and 3.3% for robotic RP. Two-year probability of recurrence analyzed by surgeon, adjusted for risk, ranged from a low of 2.5% to a high of 4.8%.

"Differences between surgeons were larger than differences between surgical approaches," said Dr. Silberstein.