Bilateral sentinel lymph node biopsy safe alternative for assessing early cervical cancer




SAN DIEGO – Bilateral sentinel lymph node biopsy alone is a safe alternative to bilateral pelvic lymphadenectomy for stage I cervical cancer and might reduce morbidity, results from an observational study suggest.

“Prior studies have shown detection rates for sentinel lymph nodes and sensitivity for metastases of approximately 95% for cervical tumors less than 2 cm,” Dr. Genevieve K. Lennox said at the annual meeting of the Society of Gynecologic Oncology. “To our knowledge, ours is the first study specifically investigating the long-term outcomes for patients who have had bilateral sentinel lymph node biopsy alone for lymph node assessment in stage I cervical cancer.”

Dr. Genevieve K. Lennox

Dr. Genevieve K. Lennox

Dr. Lennox, a gynecologic oncology fellow in the department of ob.gyn. at the University of Toronto, and her associates used the university’s prospective cervical cancer database to identify 1,188 patients with stage IA/IB cervical cancer with negative lymph nodes on pathology after primary surgery with either bilateral pelvic lymphadenectomy (BPLND) or bilateral sentinel lymph node biopsy (BSLNB). They used Wilcoxon rank sum, chi square, and Fisher’s exact tests to compare the two groups, and a Cox proportional hazards model to identify predictors of recurrence-free survival.

The researchers observed no differences in recurrence-free survival between BPLND and BSLNB at 2 years (95% vs. 97%, respectively) or at 5 years (92% vs. 93%), nor in tumor size, histology, depth of invasion, intra-operative complications, or short-term morbidity. BPLND was, however, associated with increased surgical time (2.8 vs. 2 hours for BSLNB; P less than .001), blood loss (500 mL vs. 100 mL; P less than .001), transfusion (23% vs. 0%; P less than .001), and postoperative infection (11% vs. 0%; P = .001). Age, surgical date, stage, lymphovascular space invasion, and radicality of surgery differed between groups, she reported.

After controlling for confounders on multivariable cox regression analysis, only tumor size, lymphovascular space invasion, and histology were prognostic for recurrence-free survival, but mode of lymph node assessment was not.

“Seeing the data, it struck me how much less invasive the treatment of early cervical cancer has become over the past 20 years,” Dr. Lennox said. “Based on our data, it appears that bilateral sentinel lymph node biopsy alone is a safe alternative to bilateral pelvic lymphadenectomy for stage I cervical cancer and might reduce morbidity.”

She acknowledged certain limitations of the study, including its observational design and low recurrence rate. “However, to conduct a noninferiority trial with a 3% margin, assuming a 5-year recurrence rate of 7% in the pelvic lymphadenectomy group and 10% in the sentinel lymph node biopsy group, would require approximately 1,400 patients,” Dr. Lennox noted. “Since such a study is not feasible, we will have to continue accumulating data from prospective observational studies to inform decision making about the use of the sentinel lymph node strategy in cervical cancer.”

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