Sentinel Lymph Node Biopsy in Cervical Cancer Matches Pelvic Lymphadenectomy

Sentinel lymph node (SLN) biopsy for early cervical cancer achieved non-inferiority versus pelvic lymphadenectomy, according to results of a large randomized study from China.

Patients assigned to SLN had a 3-year disease-free survival (DFS) of 96.8% as compared with 94.5% for the pelvic lymphadenectomy group. Unexpectedly, 3-year overall survival (OS) with SLN was significantly higher than with standard care (100% vs 97.8%). As expected, pelvic lymphadenectomy was associated with more surgical and postoperative adverse events (AEs).

“Our findings suggest that, in the condition of negative sentinel lymph nodes, omitting pelvic lymphadenectomy does not compromise disease-free survival of cervical cancer patients compared to completing pelvic lymphadenectomy and potentially improve OS,” said Jihong Liu, MD, of Sun Yat-sen University in Guangzhou, China, at the Society of Gynecologic Oncology (SGO) annual meeting in Seattle. “We also found that SLN biopsy alone without further lymphadenectomy decreased retroperitoneal lymph node recurrence and reduced surgical complications.”

The results confirm that SLN biopsy concurrent with radical hysterectomy is standard of care for patients with early cervical cancer, said SGO invited discussant Premal H. Thaker, MD, of Washington University in St. Louis.

“I believe we really have moved the needle by decreasing adverse events for our cervical cancer patients by performing sentinel lymph node biopsy at the time of radical hysterectomy,” said Thaker.

The previously reported open-label SENTICOL-II trial showed an SLN detection rate of 97% with a dual-technique approach for identifying sentinel nodes (as compared with a single technique in the current study) and no detriment to recurrence, she continued. The ongoing SENTICOL-III trial will further inform decision making by randomized comparison of SLN, by dual-technique identification, or pelvic lymphadenectomy, after radical hysterectomy or trachelectomy.

Liu reported initial findings from the PHENIX-1 trial, the first randomized clinical study comparing SLN biopsy and pelvic lymphadenectomy in patients with early-stage cervical cancer. The diagnostic utility of SLN has been confirmed in multiple studies, and prospective evaluations also have shown that SLN improves quality of life, creating support for SLN as standard of care, she said. However, confirmatory data from a randomized trial had been lacking.

Investigators throughout China enrolled patients with FIGO staged IA1-IIA1 cervical cancer. The patients were evaluated by SLN biopsy and frozen section, and those with negative findings were randomized to radical hysterectomy with or without lymphadenectomy, followed by standard-of-care postoperative management. Liu reported findings only for patients with negative SLN results. Findings for SLN biopsy-positive results will be reported separately at a later date.

The trial’s primary endpoint was 3-year DFS. Investigators assumed a 3-year DFS of 89% with SLN biopsy and 94% with pelvic lymphadenectomy. The trial was powered to demonstrate a non-inferiority hazard ratio of 1.88 for SLN versus pelvic lymphadenectomy.

Analysis of baseline characteristics showed no imbalances between the two groups, including performance status, histology, grade, stage, tumor size, or surgical approach (laparotomy or laparoscopy). Only one type of tracer was used for SLN detection, which was methylene blue dye in 85% of cases and indocyanine green in 14%. Data analysis included 833 randomized patients.

The results showed 16 recurrences in the SLN arm versus 26 in the patients who had pelvic lymphadenectomy. More patients assigned to pelvic lymphadenectomy had retroperitoneal recurrences (nine vs none) and multiple sites of recurrence (eight vs none). Three-fourths of pelvic lymphadenectomy were performed laparoscopically, and Thaker noted that as a possible contributing factor to the outcomes.

Three patients in the SLN arm died as compared with 14 in the pelvic lymphadenectomy group, which translated into a 39% reduction in the hazard for DFS at 3 years (95% CI 0.33-1.14, P=0.12). The 2.2% absolute difference in 3-year OS represented a 79% reduction in the hazard, which achieved statistical significance (95% CI 0.06-0.74, P=0.007).

Surgical outcomes favored SLN biopsy, as pelvic lymphadenectomy was associated with significantly longer operation time (221 vs 189 minutes, P<0.0001), greater blood loss (160 vs 130 mL, P=0.001), days of antibiotic use (4.0 vs 3.0, P=0.032), and intraoperative complications (13 vs 4, P=0.028). AEs occurred more frequently with pelvic lymphadenectomy (244 vs 195, P=0.001), including pain (24 vs 7, P=0.002), lymphocyst (92 vs 35, P<0.0001), and lymphedema (42 vs 10, P<0.0001).

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