LAUSR

The purpose of this article was to report the treatment effect of image-guided high-dose-rate interstitial brachytherapy boost in the radical radiotherapy for a huge metastatic carcinoma of cervical lymph nodes from an unknown primary site. The patient was a 75-year-old male. A diagnostic biopsy showed metastatic squamous cell carcinoma and the tumour size was 7.5×6.5×11.5cm3 before treatment (N3; AJCC 7th). After external beam radiotherapy with a dose of 60Gy in 30 fractions, the residual tumour (6.2×4.7×6.0cm3) was treated with image-guided high-dose-rate interstitial brachytherapy boost under ultrasound guidance. The brachytherapy dose was 16Gy in four fractions of 4Gy each. Removal of the huge metastatic tumour was securely achieved by high dose rate interstitial brachytherapy guided with ultrasound scanning. The refractory tumour in the patients healed uneventfully after image-guided high-dose-rate interstitial brachytherapy without recurrence during the 24 months of follow-up. The image-guided high-dose-rate interstitial brachytherapy boost may be a proposed treatment strategy for metastatic carcinoma of cervical lymph nodes from an unknown primary site with radical radiotherapy, especially for huge residual tumour.