Results of a retrospective, inter-institutional study comparing outcomes of patients with urothelial carcinoma of the bladder highly favor the use of an extended template for bilateral pelvic lymph node dissection (PLND) when performing radical cystectomy.
Anaheim, CA-Results of a retrospective, inter-institutional study comparing outcomes of patients with urothelial carcinoma of the bladder highly favor the use of an extended template for bilateral pelvic lymph node dissection (PLND) when performing radical cystectomy, researchers reported at the AUA annual meeting of the American Urological Association.
"Recognizing the inherent limitations of the study, the results suggest that limited PLND is associated with suboptimal staging and a higher incidence of progression in patients with pT2 and pT3 disease. An extended PLND appears to not only allow for more accurate staging, but also for improved survival in organ-confined and non-organ-confined LN-positive and LN-negative patients," said first author Nivedita Dhar, MD, a former clinical research fellow at the University of Bern, Switzerland, working with Urs E. Studer, MD, and colleagues.
The study included two consecutive, concurrent series of patients operated on between 1987 and 2000. One group comprised 336 patients treated at the Cleveland Clinic who received limited PLND with a median of 12 nodes removed per patient (range, 2 to 31 nodes). In the second group, 322 patients were operated on at the University of Bern, where an extended template was used for the PLND. The median number of nodes removed per patient in this group was 22 (range, 10 to 43 nodes). None of the patients in the two series received neoadjuvant radiotherapy or chemotherapy.
"Patients with pT1 disease have only a 5% to 8% incidence of positive nodes, and patients with pT4 cancer have such advanced disease, any differences in survival identified between the two groups in our study would likely not be related to the extent of dissection," explained Dr. Dhar, currently an associate staff urologist at the Cleveland Clinic.
Median postoperative follow-up was 45.1 months (range, 1 to 166 months) for the Cleveland Clinic patients and 58.7 months (range, 1 to 229 months) for the patients at the University of Bern.
The Cleveland Clinic group included 200 patients with pT2 disease and 136 patients with pT3 disease. In the Bern series, 150 patients had pT2 disease and 172 patients had pT3 disease. When categorized by pathologic stage, the incidence of positive nodes was statistically significantly higher in the group operated on with the extended template than it was in the limited dissection group for patients with pT2 (16% vs. 7.5%) and pT3 (34% vs. 21%) disease.
The proportion of patients found to be node-positive was nearly two-fold higher in the extended PLND series than in the limited PLND group (26% vs.13%), Dr. Dhar reported.
Recurrence linked to procedure
Analysis of recurrences among node-positive patients showed that the 5-year recurrence-free survival rate was significantly higher for the extended PLND group compared with that for the limited PLND group (35% vs. 7%), possibly because the patients who underwent limited PLND have additional positive nodes that were not removed. For patients who were node-negative and with the analysis stratifying patients by pathologic stage, 5-year recurrence-free survival rates also were significantly higher in those who underwent the extended versus limited PLND for both the pT2 (77% vs. 67%) and pT3 subgroups (57% vs. 23%).
"The observed benefits for the extended technique may be explained by the possibility that the limited dissection is more likely to leave patients harboring undetected positive nodes after surgery, thereby compromising their outcome," Dr. Dhar said.
However, to rule out that the differences between groups were not due to a "Will Rogers phenomenon"-the apparent paradox obtained when moving patients from one group to another (ie, from the pN0 group to the pN+ group)-recurrence-free survival rates were also calculated with patients pooled regardless of nodal status. Still, the 5-year recurrence-free survival was also significantly higher for the extended PLND patients than for the limited dissection group (59% vs. 45%).
"If use of the extended template accounts for this difference, we would expect to see recurrence-free survival differences for pT2 and pT3 patients, regardless of nodal status," Dr. Dhar said.