Takeaway
- Intraoperative freehand single photon emission computed tomography (fhSPECT) showed excellent sentinel node (SN) identification in patients with oral cancer.
- fhSPECT had low false negative but high false positive rate.
Why this matters
- Traditional lymphoscintigraphy (LSG) and/or single photon emission computed tomography (SPECT) have disadvantages including the requirement for a nuclear medicine department and radiotracer injection up to 24 h before surgery, and the tumour must be readily accessible.
- These data show that a surgeon who is naïve to the results of pre-operative imaging can use fhSPECT in the operating theatre to accurately locate SNs in oral cancer.
Results
- 144 SNs were retrieved - average 2.88 (±2.05) nodes per patient (range 1-8).
- 95 SNs were identified by lymphoscintigraphy, 122 by SPECT/CT, and 125 by fhSPECT.
- SN biopsy was positive for metastasis in 19 patients (38%).
- 15 patients underwent fhSPECT scan.
- In 3 cases there was no clear drainage to the neck.
- In 2 cases there was drainage to the neck but the signal could not be isolated.
- 10 cases had hot nodal areas.
- All modalities missed positive nodes in ≥1 patient.
- False negative rate (FNR) for lymphoscintigraphy, SPECT/CT and fhSPECT was 26.3%, 15.8%, and 5.3%, respectively.
Study design
- 50 consecutive cT1-T2 N0 oral cancer patients were recruited to receive radiotracer followed by lymphoscintigraphy and SPECT/CT. Surgery was undertaken using fhSPECT by a surgeon blinded to pre-operative imaging.
- Prior to biopsy completion, results of pre-operative imaging were reviewed and any additional nodes removed. The accuracy of LSG, SPECT/CT, and fhSPECT were compared.
- Funding: none specified.
Limitations
- Not all patients could be scanned immediately post-injection, which was due to clashing scheduling of both surgery and injection.
- This study protocol did not allow delay of more than 10 min between injection of tracer and commencement of lymphoscintigraphy.
References
References