PET-CT appears to be feasible and safe in extraperitoneal laparoscopic para-aortic lymphadenectomy for locally advanced cervical cancer, researchers said here at the Society of Gynecologic Oncologists (SGO) 41st Annual Meeting on Women's Cancer.

One of the most serious difficulties in treating locally advanced cervical cancer is appropriate staging. Understaging disease can easily lead to undertreatment.

"Clinical staging of cervical cancer almost always underestimates the true extent of metastatic disease," said Pedro Ramirez, MD, University of Texas M. D. Anderson Cancer Center, Houston, Texas, on March 16. "The most important indicator of recurrence is para-aortic node status, but imaging has been limited in detecting para-aortic metastases because of low sensitivity."

According to Dr. Ramirez, CT scans have a sensitivity of 34% for para-aortic metastases, and magnetic resonance imaging ( MRI ) offers 30% sensitivity. PET-CT is generally accepted as offering more useful images than either CT or MRI, but false-negatives have been a problem in the past.

Researchers at M. D. Anderson added positron emission tomography/computed tomography ( PET-CT ) imaging to a prospective trial using extraperitoneal laparoscopic para-aortic lymphadenectomy in locally advanced stage IB2 to IVA cervical cancer.

The goal was to evaluate the safety and feasibility of extraperitoneal laparoscopic para-aortic lymphadenectomy and the efficacy of presurgical PET-CT studies in detecting histopathologically positive metastases to the para-aortic lymph nodes.

Researchers opened the trial to women with biopsy-proven cervical cancer of any histology and no evidence of positive para-aortic lymph nodes on preoperative CT or MRI. Women were also given a preop PET-CT no more than 6 weeks prior to surgery.

The trial accrued only 65 women between 2003 and 2009, Dr. Ramirez said, and 5 women were excluded from the final analysis. The median age was 48 and women had the PET-CT scan a median of 3 days before surgery.

The procedure itself took a median of 140 minutes and patients lost a median of 25 mL of blood. The median length of stay was 1 day, including 5 patients who had surgery as an outpatient procedure. There was only 1 intraoperative complication and 7 postoperative complications.

Surgeons removed a median of 11 nodes. Of the 60 patients included in the analysis, 13 (22%) had positive para-aortic nodes. Of those 13, 7 (54%) had grossly positive nodes. The median time to initiation of radiotherapy after surgery was 10 days.

A total of 26 patients showed negative pelvic and para-aortic nodes on PET-CT; of the group, 2 (8%) were found to have positive para-aortic nodes. A total of 27 patients showed positive pelvic nodes and negative para-aortic nodes; 6 (22%) were found to have positive para-aortic nodes. Seven patients showed positive pelvic and positive para-aortic nodes; 5 (77%) were found to have positive para-aortic nodes. The findings yielded a sensitivity for para-aortic metastases of 38.5%, specificity of 95.7%, positive predictive value of 71.4%, and negative predictive value of 84.9%.

"We found PET-CT and the extraperitoneal laparoscopic para-aortic lymphadenectomy to be feasible and safe," Dr. Ramirez concluded, "but we need further trials to assess the impact on survival."

The study is currently open and accruing patients to assess the role of PET-CT and other imaging modalities in assessing para-aortic lymph node metastases.

Source: SGO

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