Otolaryngologists-head and neck surgeons have suggested that performing tonsillectomy among patients who present with neck metastases from an occult primary tumor can identify a high percentage of primary tumors-an even better success rate in locating the malignancies than can be obtained with deep tonsil biopsy.
The overall yield of finding occult primary carcinoma in the tonsil was 3.2 percent for deep tonsil biopsies versus 29.6 percent for tonsillectomies, said Joshua D. Waltonen, MD, Assistant Professor of Otolaryngology at Wake Forest University in Winston-Salem, NC.
Identification of the primary tumor site allows for precise treatment planning, and may obviate the need for wide-field radiation therapy, he said in his presentation at the 111th annual meeting of the Triological Society.
A Retrospective Review
Dr. Waltonen and his colleagues at the James Comprehensive Cancer Center at Ohio State University in Columbus reviewed charts of patients presenting with occult primary head and neck cancers over a 10-year period, reviewing records from January 1997 through June 2007 among patients diagnosed with metastatic cancer of the neck with an unknown primary origin.
The record review identified 122 patients-90 of whom were men-between the ages of 31 and 88 years, with a median age of 56 years. About 92% of the patients were diagnosed with a squamous cell cancer, and the other 8% of the patients were diagnosed with poorly differentiated carcinoma. The retrospective study excluded cases of nonsquamous histology.
In the study, Dr. Waltonen compared success in locating the primary tumors between patients who underwent a tonsil biopsy and those who had a tonsillectomy. We are unaware of any studies that compare these methods, so we set about to perform our retrospective study, he said.
About 81% of the patients had already undergone computed tomography (CT) scans; about 7% had magnetic resonance imaging; 26% had undergone positron emission tomography (PET); and 21% of the patients had a PET-CT fusion scan performed-without any of the imaging modalities being able to locate the primary tumor. Panendoscopy was also performed in all the patients, but again the primary tumor remained elusive.
The theoretical risk of bilateral tonsillectomy is twice that of unilateral tonsillectomy.
-Mark Weissler, MD
In addition to the imaging studies, the patients also underwent multiple biopsies. All patients had bilateral biopsies of the nasopharynx, tongue base, and hypopharynx, Dr. Waltonen said. The patients’ tonsils were addressed according to the preferences of the attending physicians. The biopsies were all performed under the same anesthesia procedure.
In the cases reviewed, physicians performed deep tonsil biopsies in 95 patients and tonsillectomy in 27 patients- 11 bilateral tonsillectomies and 16 unilateral tonsillectomies. The procedures themselves-endoscopies, biopsies, and tonsillectomies-did not appear to carry any additional complications in this series.
Among the 95 patients in whom the deep tonsil biopsy was performed, the primary cancer was identified in 11 cases-about 12% of these patients; among the 27 patients in whom partial or complete tonsillectomy was performed, the primary tumor was identified in 11 cases-about 41% of these patients (p = 0.013), Dr. Waltonen reported.
Primary tumors in the tonsils were identified in three patients who had biopsies of the tonsil, and in eight patients who underwent tonsillectomies (p < 0.0002). Dr. Waltonen said that the series of cases he reviewed appears to be similar in its findings to several other studies reported in the literature, which indicate the yield of locating the primary tumor in these cases is about 30% if tonsillectomy is performed.
All the primary tonsil cancers identified were ipsilateral to the presenting neck metastases, he said. In 100 patients, doctors could not determine the primary tumor location prior to initiating treatment. After completion of treatment, three of those primaries emerged: one in the lung, one in the nasal cavity, and one in the tonsil-and that individual had undergone a tonsil biopsy, which was negative.
Implications
The situation in which we are faced with treating patients with unknown primary cancer is common, he said. These occult tumors represent about 3 to 5 percent of head and neck cancer population. A great deal of effort is put forth in identifying the primary tumor site.
In patients with primary tumors that remain occult despite thorough diagnostic workup, the likelihood of successful identification of tonsillar primary tumor is improved by performing tonsillectomy, Dr. Waltonen said.
Given that half the primary tumors we discovered were outside the tonsils, we continue to advocate directed biopsies of other potential mucosal sites, especially the tongue base, he said. In his series, eight primary tumors of the tongue base were identified.
Limitations
I believe this is an important finding, though the study suffers from small size and its retrospective nature, said Mark Weissler, MD, the Joseph P. Riddle Distinguished Professor of Otolaryngology and Chief of the Division of Head and Neck Oncology at the University of North Carolina in Chapel Hill.
Dr. Weissler, noting that all the tumors were located in the ipsilateral tonsil, suggested that the complication rate could increase if bilateral tonsillectomies were performed regularly. Even though no complications were reported in this series, he noted, The theoretical risk of bilateral tonsillectomy is twice that of unilateral tonsillectomy.
©2009 The Triological Society