Stepwise Diagnosis Helps Identify Primary Tumors in Majority of Patients

What is the cumulative effect of diagnostic steps for primary tumor identification in patients with head and neck squamous cell carcinoma of unknown primary (HNSCCUP)?

Bottom Line: A stepwise approach to primary tumor identification identifies a primary tumor in a majority of patients.

Background: After an initial history and physical examination, and determining the metastasis’ HPV status, HNSCCUP evaluation aims at primary tumor identification. This begins with diagnostic imaging (CT, MRI, and/or fluorodeoxyglucose-positron emission tomography [FDG-PET]/CT), then ipsilateral palatine tonsillectomy if needed, then bilateral palatine tonsillectomy if needed. Although the effectiveness of each has been evaluated individually, there is a lack of data on their cumulative effect applied in sequence.

Study design: Retrospective analysis of 110 patients diagnosed with HNSCCUP between 2003 and 2015.

Setting: Johns Hopkins Bloomberg School of Public Health, Baltimore.

Synopsis: All patients underwent direct laryngoscopy with biopsy of suspicious lesions, which identified a primary tumor in 34 patients. Forty-seven patients underwent palatine tonsillectomy, with 17 identified with primary tumors. Fourteen patients underwent subsequent TORS lingual tonsillectomy, and eight primary tumors were identified. FDG-PET/CT was used prior to operative diagnostic evaluation in 77 patients. Among these, 23 were suspicious for a primary site. Ten of the 23 had the primary tumor identified by direct laryngoscopy. Seven additional tonsillar primaries were identified by palatine tonsillectomy, yielding a cumulative identification of 17 of 23. Twenty-five of 54 primary tumors were cumulatively identified in patients with negative FDG-PET/CT. For 80 HPV-positive patients, 29 primary tumors were identified after direct laryngoscopy with biopsies. Thirty-four underwent palatine tonsillectomy; fifteen of these revealed the primary tumor. Eleven underwent TORS lingual tonsillectomy, which identified eight new primaries. Patients with HPV-positive tumors had longer overall survival rates than patients with HPV-negative tumors. Limitations included the study’s retrospective nature, data from a single institution, nonrandom diagnostic evaluation and treatment variations, and outcomes that are not necessarily generalizable.

Images from treatment plans illustrating differences in radiation treatment for a patient with (A) an identified HPV-positive base-of-tongue primary tumor, (B) an HPV-positive metastasis without identified primary, and (C) an HPV-negative metastasis without identified primary.
© 2019 The American Laryngological, Rhinological and Otological Society, Inc.