Positron emission tomography: poor sensitivity for occult tonsillar cancer

Nabili, Vishad; Zaia, Brita; Blackwell, Keith E.; Head, Christian S.; Grabski, Karsten; Sercarz, Joel A.

doi:10.1016/j.amjoto.2006.08.001

« Previous Next »American Journal of Otolaryngology - Head and Neck Medicine and Surgery
Volume 28, Issue 3 , Pages 153-157, May 2007

Positron emission tomography: poor sensitivity for occult tonsillar cancer

Presented at the Annual Western Section Meeting of Triological Society in Las Vegas, NV, on February 5, 2005.

Vishad Nabili, MD
- Division of Head and Neck Surgery-Otolaryngology, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, CA, USA
Brita Zaia, MD
- Division of Head and Neck Surgery-Otolaryngology, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, CA, USA
Keith E. Blackwell, MD
- Division of Head and Neck Surgery-Otolaryngology, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, CA, USA
Christian S. Head, MD
- Division of Head and Neck Surgery-Otolaryngology, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, CA, USA
Karsten Grabski, MD
- Department of Nuclear Medicine, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA
Joel A. Sercarz, MD
- Division of Head and Neck Surgery-Otolaryngology, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, CA, USA
- Corresponding author. Division of Head and Neck Surgery-Otolaryngology, David Geffen School of Medicine at UCLA, 10833 Le Conte Ave, RM 62-132, CHS, Los Angeles, CA 90095, USA. Tel.: +1 310 825 5179.

Received 12 July 2006

Abstract

Purpose

The aim of the study was to determine the sensitivity of preoperative positron emission tomography (PET) scans in the detection of primary tumors of the tonsils.

Materials and methods

We conducted a retrospective review of 46 patients treated at a university medical center for occult tonsillar cancer during the years 2002 to 2004. We identified patients who underwent a preoperative PET scan to locate an unknown primary tumor. Fusion computed tomography with PET (PET/CT) was used to further delineate anatomic localization to the tonsil area. A positive PET/CT scan was defined as asymmetric increased tracer uptake in the tonsil and/or tonsillar fossa ipsilateral to the tonsillar cancer site when compared with the contralateral site. A negative PET/CT scan was defined as equivocal symmetric tracer uptake bilaterally.

Results

Of the 46 patients, 6 (13.0%) had pretreatment PET scans. Of these 6 patients, 16.7% (n = 1) had positive PET, 66.7% (n = 4) had negative PET, and 16.7% (n = 1) demonstrated increased tracer uptake in tonsils bilaterally greater on the side contralateral to the cancer. In this group, PET scans had a sensitivity of 0.167 and false-negative ratio of 0.667 for tonsillar cancer detection.

Conclusions

Although the patient population in this study is small (n = 6), the findings suggest that PET/ CT scans may offer a low sensitivity in detection of primary tonsillar cancers. However, PET/CT scans still have a significant role in the detection of other unknown primary head and neck tumors. Technical reasons for this finding are discussed.