Purpose: The radioactive gold grain applicator and seeds offer the flexibility necessary for effective use in the treatment of difficult sites of head-and-neck cancers. This study reviews our experience with gold grain (198Au) implants in locally advanced head-and-neck cancer to demonstrate their efficacy and feasibility.
Methods and materials: This study reviewed the charts of 94 patients who were treated with gold grain implants (1970-1995) and who were treated with radioactive 198Au implants. Thirty-seven of the subjects had implants located in the head-and-neck region, and these form the basis for this report. Of these, eight of the cases were located in the supraglottic larynx, five in the nasopharynx, four in the retromolar trigone, two in the oral cavity, four in the base of the tongue, four in the maxillary antrum, four in the palate, two in metastatic cervical lymph nodes (of unknown primary tumor), two in the tonsillar fossa, one in the pyriform fossa, and one in the posterior pharyngeal wall. Twenty-eight were recurrent cases after prior surgeries and radiation. Six were residual locally advanced cases, and 3 patients had their implants for a second primary tumor in an area that had been irradiated before. The gold grains were inserted with a Royal Marsden gun and 198Au, 130-180 MBq per seed. The median number of seeds implanted was 34. The total radiation dose, delivered at a margin of 0.5 cm around the target volume, ranged from 40 to 120 Gy, with a median of 80 Gy.
Results: Complete local control was achieved in 33% and was contingent on two factors: (1) the size of the lesion implanted and (2) the histology and possible primary tumor site. In 19 tumors with a diameter greater than 2.5 cm, only 2 (11%) had complete tumor control. Conversely, 9 of 14 patients (64%) who had lesions smaller than 2.5 cm experienced successful local control (p = 0.002). Palatal-adenoid-cystic tumors had an average progression-free survival of 52 months, compared with 13, 9, and 4 months, respectively, in nasopharyngeal, oropharyngeal, and supraglottic squamous cell carcinoma. Palliation was successfully accomplished in 76% of the cases. Cessation of bleeding occurred in 50% of the subjects, pain control was achieved in 88%, and 60% experienced relief of dysphagia.
Conclusions: Gold grain implants have a role in the palliation of recurrent head-and-neck tumors, particularly for sites difficult to reach via other techniques, such as the supraglottic larynx, base of the tongue, hypopharynx, and the nasopharynx. Local control is best achieved in lesions less than 2.5 cm in dimension and is most successful in slow-growing tumors.