Sonography for the detection of cervical lymph node metastases among patients with tongue cancer: Criteria for early detection and assessment of follow-up examination intervals

BACKGROUND AND PURPOSE: Because the presence of cervical metastasis is one of the factors influencing the outcome of patients with carcinoma of the he ad and neck, its early detection is potentially very important. The purpose of this study was to evaluate the characteristic changes of cervical metas tasis revealed by sonography during follow-up and to assess an adequate int erval for follow-up sonography of the neck among patients with tongue cance r, METHODS: Forty-three of 44 consecutive patients with squamous cell carcinom a of the tongue, who had undergone interstitial brachytherapy, were examine d with sonography of the neck during the posttherapeutic follow-up period. RESULTS: Seventeen cervical lymph node metastases were found in 12 of 43 pa tients during follow-up. Of these 17 cervical metastases, 16 (94.1%) were a ccurately diagnosed and one (5.9%) was misdiagnosed as nonmetastatic based on sonographic findings, Sonography of the neck performed in seven patients at an interval of less than 1 month since the last follow-up imaging showe d 9 (90.0%) of 10 metastases increased by up to 2 mm in short-axis diameter . Five patients who were followed up at an interval of more than 1 month si nce the last followup imaging had seven metastases increase by 3 to 8 mm in short-axis diameter or a change of echogenicity in the internal structure of lymph nodes or both. Pathologic examinations showed extranodal spread in 3 (42.9%) of these 7 metastases. CONCLUSION: Changes both in size and internal echogenicity can occur as qui ckly as 2 to 4 weeks between sonographic examinations. Therefore, in high-r isk patients, or in those with suspicious sonographic findings, short-inter val follow-up sonographic examinations are recommended at least during the first posttherapeutic year. Our findings suggest that follow-up sonography of the neck should be performed monthly, at least during the first postther apeutic year.