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Correlation of Isotope Count With Sentinel Node Positivity in Vulvar Cancer
  1. Linn Woelber, MD, PhD*,
  2. Simon A. Joosse, PhD,
  3. Donata Grimm, MD*,
  4. Sabrina Mathey, MD*,
  5. Sven Mahner, MD, PhD,
  6. Eike Burandt, MD, PhD§,
  7. Susanne Klutmann, MD, PhD,
  8. Barbara Schmalfeldt, MD, PhD* and
  9. Katharina Prieske, MD*
  1. *Departments of Gynecology and Gynecologic Oncology, and
  2. Tumor Biology, University Medical Center Hamburg-Eppendorf;
  3. Department of Obstetrics and Gynecology, Ludwig-Maximillians- University Munich, Munich;
  4. §Institute of Pathology; and
  5. Department for Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
  1. Address correspondence and reprint requests to Linn Woelber, MD, PhD, Department of Gynecology and Gynecologic Oncology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246 Hamburg, Germany. E-mail: lwoelber{at}


Objective Sentinel node biopsy (SNB) has become standard of care in early stage vulvar cancer. As the correlation of isotope count with the presence of metastases remains unclear, often several active nodes are excised per groin. This can result in increased morbidity in node-negative disease despite of SNB. In the current analysis, we assess whether resection of the hottest node could be sufficient to detect sentinel lymph node (SLN) metastasis.

Methods Patients with primary vulvar cancer receiving an SNB with radioactive tracer at the University Medical Center Hamburg-Eppendorf between 2008 and 2015 were evaluated.

Results A total of 145 patients with SNB were analyzed; thereof, 144 underwent bilateral SNB, resulting in 289 analyzed groins. A median of 2 SLNs (range, 1–7) per groin were removed. From 94 (32.5%) of 289 groins, more than 2 SLNs were excised. Median overall SLN isotope count was 1400 cps. In 50 groins, a positive SLN was detected (unilateral in 38 patients, bilateral in 6). The median number of positive SLN per groin was 1 (range, 1–4). The SLN with the highest isotope count carried metastases in 36 (78.3%) of 46 groins (in 4 cases, the highest count was unknown). In 10 (21.7%) of 46 positive groins, the SLN with the highest count was not the metastatic SLN (9/10 second highest count). Median count of these 10 SLN was 60% of the highest count with a range from 11.0% to 74.0%.

Conclusions The highest isotope count does not reliably detect the positive SLN in vulvar cancer. To prevent mostly fatal groin recurrences, surgeons should continue to remove all SLN accumulating relevant radioactive tracer over background activity.

  • Vulvar cancer
  • Sentinel
  • Groin
  • Isotope count
  • Metastases

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  • This study was funded by internal departmental sources.

  • The authors declare no conflicts of interest.

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