Complete Response Demonstrated by [ 11 C]methionine-PET Imaging of a Patient With Squamous-cell Carcinoma of the Tongue Treated With Chemotherapy, Immunotherapy and Methionine Restriction Without Radiation or Surgery: A Potential New Low-toxicity Treatment Paradigm for a Recalcitrant Disease.
Tomoyuki Ishiguro, Toshihiko Sato, Qinghong Han et al.
✦ AI-curated · Sources linked
Case in brief
A 58-year-old man had HPV-positive squamous-cell carcinoma of the tongue base with extensive cervical lymph-node involvement (cT1N3M0). Concerned about functional impairment and disfigurement, he chose not to undergo surgery or radiotherapy. He received seven cycles of docetaxel, cisplatinum, and 5-fluorouracil with a low-methionine diet and oral recombinant methioninase; pembrolizumab began during cycle five and continued as maintenance. The cervical tumor regressed and became clinically undetectable. Follow-up [11C]methionine-PET/CT and [18F]FDG-PET/CT showed no active disease, consistent with complete response. He remained clinically well without recurrence while continuing pembrolizumab and methionine restriction.
What made this case unusual
Complete clinical and metabolic response was reported after systemic combination treatment with methionine restriction, without surgery or radiotherapy, in locally advanced HPV-positive tongue cancer.
Diagnostic / clinical pearl
PET/CT with both [11C]methionine and [18F]FDG documented no evidence of active disease in this case; imaging findings supported the reported complete response.
Why it matters
The report raises methionine restriction as a possible adjunct to systemic treatment, but further case series and prospective studies are needed to assess efficacy, safety, and generalizability.