Suzanne K. Chambers, PhD
In an Australian phase III trial reported in The Lancet Oncology, Suzanne K. Chambers, PhD, of the Menzies Health Institute Queensland, Griffith University, Gold Coast, and colleagues found similar functional outcomes at 2 years with robot-assisted laparoscopic prostatectomy and open radical retropubic prostatectomy in men with newly diagnosed clinically localized prostate cancer.
In the trial, 326 men aged 35 to 70 years recruited from Royal Brisbane and Women’s Hospital who elected surgery were randomized between August 2010 and November 2014 to undergo robot-assisted laparoscopic prostatectomy (n = 157 after 6 dropouts) or open radical retropubic prostatectomy (n = 151 after 12 dropouts).
Primary outcomes were urinary function and sexual function, as assessed by the Expanded Prostate Cancer Index Composite (EPIC) and International Index of Erectile Function Questionnaire (IIEF) at 6, 12, and 24 months, and oncologic outcomes of biochemical recurrence and imaging evidence of progression. Equivalence of outcomes was examined by two one-sided t test procedures (based on findings in two external cohorts of patients undergoing surgery), with equivalence established when P values for both t tests were significant.
Functional and Oncologic Outcomes
At 24-month follow-up, 150 men remained in the robot-assisted laparoscopic prostatectomy group and 146 in the open radical retropubic prostatectomy group.
Urinary function scores did not differ significantly between robot-assisted laparoscopic prostatectomy vs open radical retropubic prostatectomy at 6 months (88.68 vs 88.45), 12 months (90.76 vs 91.53), or 24 months after surgery (91.33 vs 90.86). Sexual function scores did not differ significantly at 6 months (37.40 vs 38.63 on EPIC, 29.75 vs 29.78 on IIEF), 12 months (42.28 vs 42.51 on EPIC, 33.10 vs 33.50 on IIEF), or 24 months (45.70 vs 46.90 on EPIC, 33.95 vs 33.89 on IIEF).
Equivalence testing of the difference in incidence of biochemical recurrence in the two groups (3% in the robot-assisted laparoscopic prostatectomy group vs 9% in the open radical retropubic prostatectomy group; difference = 0.06, 90% confidence interval = 0.02–0.10) indicated that equality could not be established (based on a 90% confidence interval with a prespecified margin of 10%). Superiority testing showed a significant difference (P = .0199). Equivalence testing of the difference in incidence of imaging evidence of progression indicated no significant difference between groups (1% vs 2%, P = .2956).
The investigators concluded, “Robot-assisted laparoscopic prostatectomy and open radical retropubic prostatectomy yielded similar functional outcomes at 24 months. We advise caution in interpreting the oncological outcomes of our study because of the absence of standardisation in postoperative management between the two trial groups and the use of additional cancer treatments. Clinicians and patients should view the benefits of a robotic approach as being largely related to its minimally invasive nature.” ■