Diagnostic work-up and outcome of cervical metastases from an unknown primary

CONCLUSIONS: An intensive diagnostic work-up including (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) detects many unknown primary tumours, leads to a low emergence rate of primary tumours, and selects carcinoma of unknown primary with much more favourable results after neck dissection and postoperative radiotherapy. OBJECTIVE: To investigate the optimal diagnostic approach and best treatment modality for rare head and neck cancer of unknown primary. PATIENTS AND METHODS: In a retrospective study, 69 patients admitted from 1987 to 2002 with cervical lymph node metastases without apparent primary were reviewed. Test characteristics of all diagnostic procedures were calculated. Disease-free and overall survival rates were calculated. Major prognostic factors were analysed uni-variously. RESULTS: At the primary site FDG-PET showed the best sensitivity with 69% and the highest negative predictive value with 87%. Computed tomography and magnetic resonance imaging had a better specificity with 87% and 95%, respectively. The primary tumour was detected in 23 cases (33%). Frequent primary tumour origin was the palatine tonsil (n=8, 35%), base of the tongue (n=6, 26%) and lung (n=4, 17%). All patients with unknown primary were treated by neck dissection. Adjuvant radiotherapy was performed in 26 patients (57%), concurrent radiochemotherapy was performed in 12 patients (26%). The primary emergence rate was 7%. The 5-year overall survival rate was inferior in patients with detected primary in comparison with patients with unknown primary (22% versus 52%). Significant prognostic factors in case of unknown primary were M stage, smoking, alcohol consumption and tonsillectomy. Radiotherapy but not chemotherapy with carboplatin influenced the overall survival.