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

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.

To investigate the optimal diagnostic approach and best treatment modality for rare head and neck cancer of unknown primary.

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.

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.