Very Rapid Eradication of a Large Squamous-Cell Carcinoma of the Head and Neck Treated With First-line Combination Chemotherapy, a Low-methionine Diet, and Oral Recombinant Methioninase

Abstract

Background/aim: Treatment options for squamous-cell carcinoma of the head and neck (HNSCC) include chemotherapy, surgery, radiation, and their combinations. However, these treatments have a risk of severe side-effects, including disfigurement and functional impairment. Therefore, treatment of locally-advanced or metastatic HNSCC is often challenging, and prognosis remains poor. The present case report describes the rapid eradication of a large neck HNSCC treated with first-line combination chemotherapy, a low-methionine diet, and oral recombinant methioninase (o-rMETase).

Case report: A 58-year-old male patient was diagnosed with squamous-cell carcinoma originating at the base of the tongue, with a tumor tissue-modified viral human papillomavirus (HPV) DNA score of 24,988 in October 2024. The tumor was accompanied by nearby lymph-node swelling. The tumor became a very large mass in a few months and was classified as locally-advanced HNSCC with no distant metastasis (cT1N3M0). The patient received a 3-week cycle of combination chemotherapy as first-line treatment with docetaxel (137 mg), cisplatinum (137 mg) and 5-fluorouracil (6,865 mg) administered intravenously starting April 28^th, 2025, combined with a low-methionine diet and o-rMETase (250 units twice daily). After the combination treatment was initiated, the tumor shrank rapidly, within the first few weeks, and was unnoticeable after 3 cycles of chemotherapy. Computed tomography after cessation of chemotherapy showed complete resolution of the neck mass and significant shrinkage of a lymph-node mass. The patient continues on a low-methionine diet and o-rMETase and has a normal appearance with no functional impairment. The HPV DNA score became negative after one cycle of chemotherapy.

Conclusion: The combination of first-line chemotherapy, a low-methionine diet, and o-rMETase rapidly eradicated a very large HNSCC. The present results suggest this combination should be further tested, including clinical trials, as the regimen is highly effective in the present case and can possibly avoid disfiguring surgery and harmful radiation.

Keywords: 5-fluorouracil; Head and neck cancer; Hoffman effect; chemotherapy; cisplatinum; combination therapy; docetaxel; low-methionine diet; methionine addiction; oral recombinant methioninase; rapid response; squamous cell.