Introduction: The management of patients with cervical lymph node metastases from unknown primary tumours is a major challenge in oncology. This study presents data collected from all five oncology centres in Denmark.
Materials and methods: Of the 352 consecutive patients with squamous cell or undifferentiated tumours seen from 1975 to 1995, a total of 277 (79%) were treated with radical intent. Most patients received radiotherapy to both sides of the neck as well as elective irradiation of the mucosal sites in nasopharynx, oropharynx, hypopharynx and larynx (81%). Irradiation of the ipsilateral neck only was done in 26 patients (10%). Radical surgery was the only treatment in 23 N1-N2 patients (9%).
Results: The five-year estimates of neck control, disease-specific survival and overall survival for radically treated patients were 51%, 48% and 36%, respectively. The emergence of the occult primary was observed in 66 patients (19%). About half of the emerging primaries were within the head and neck region with oropharynx, hypopharynx and oral cavity being the most common sites. Emerging primaries outside the head and neck region were primarily located in the lung (19 patients) and oesophagus (five patients). The most important factor for neck control was nodal stage (5-year estimates 69% [N1], 58% [N2] and 30% [N3]). Other important parameters for neck control and disease-specific survival included haemoglobin, gender and overall treatment time. Patients treated with ipsilateral radiotherapy had a relative risk of recurrence in the head and neck region of 1.9 compared to patients treated at both neck and mucosa. At five years, the estimated control rates were 27% (ipsilateral) and 51% (bilateral; p = 0.05). The 5-year disease-specific survival estimates were 28% and 45%, respectively (p = 0.10).
Discussion: Extensive irradiation to both sides of the neck and the mucosa in the entire pharyngeal axis and larynx resulted in significantly fewer loco-regional failures compared to patients treated with ipsilateral techniques, but only a trend towards better survival. Determination of the optimal strategy in terms of loco-regional control, survival and morbidity requires a prospective randomized trial.