Incremental (?) role of positron emission tomography/computed tomography in clinically unknown primary patients with neck metastasis.

ABSTRACT

OBJECTIVE: To study the incremental role of positron emission tomography (PET)/computed tomography (CT) in the detection of primary site in cases of occult primary with neck metastasis. STUDY DESIGN: A prospective study on 79 consecutive patients. SETTING: A tertiary care otolaryngology and head and neck surgery center. MATERIALS AND METHODS: This prospective study compares the results of PET/CT in 79 patients of occult primary with neck metastasis with that of detailed comprehensive head and neck examination including imaging and panendoscopy. This study also attempts to define the incremental role of PET/CT in patients of occult primary. RESULTS: The sensitivity of PET/CT in identifying the primary tumor was 62.4%, the specificity was 64.7%, the positive predictive value was 69.7% and the negative predictive value was 93%. We had a false positive rate of 33.6% and a false negative rate of 2.6%. CONCLUSION: PET/CT is a sensitive investigation for detection of occult primary. However, it has a low specificity rate and a high false positivity rate. Due to a high false positive rate, multiple biopsies from suspicious sites should be taken rather than solely relying on PET/CT. PET/CT guided fine needle aspiration cytology should be utilized more frequently than we did in this study.