Controversies in radiotherapy/chemotherapy in patients with neck lymph node metastases from an unknown primary tumor

Abstract

The incidence of cancer of unknown primary site with metastases to neck lymph nodes is low, according to literature it varies between 2% and 9%, and is further declining due to more precise diagnostics. Histologically, squamous cell carcinomas are most common. In addition to general physical examination with special focus on the head and neck region, endoscopic examination with visualization of nasopharynx, oropharynx, larynx and hypopharynx, and radiological imaging (CT and/or MRI, and in case of indication PET/CT) is necessary. Surgical treatment is the oldest but still very important method of treating these patients and is the preferred option for initial treatment. On the other hand, primary radiotherapyis an important treatment option for head and neck tumors, especially in patients who are not candidates for surgical treatment, and it is recommended to combine it with chemotherapy in patients with advanced disease (N2-3). After initial surgical treatment and pathohistological findings of N2 or N3 disease, radiotherapy with or without chemotherapy is indicated in all patients, and may also be considered in those with N1 status. For both primary and adjuvant radiotherapy the volume of radiation fields remains a controversial topic. Treatment options range from surgical treatment of the ipsilateral side of the neck without adjuvant treatment, surgical treatment with adjuvant (chemo)radiotherapy, to primary treatment – irradiation of both sides of the neck with all the sites from which the primary tumor could originate. Earlier, the guidelines advocated a more aggressive approach that included radiotherapy of the entire volume of the pharynx (nasopharynx, oropharynx, and hypopharynx) and larynx and both sides of the neck. Over time, there has been a noticeable shift towards more conservative treatment, most often in terms of surgical treatment of neck metastases with the use of adjuvant ipsilateral radiotherapy, without irradiating all pharyngeal and laryngeal mucosa. The most important parameters in the decision regarding concomitant chemotherapy are lymph node capsule perforation and R1 / 2 resection.

Keywords

• neoplasms
• unknown primary – diagnosis
• pathology
• therapy; squamous cell carcinoma of head and neck – diagnosis
• secondary