Long-term survivor of metastatic squamous-cell head and neck carcinoma with occult primary after cetuximab-based chemotherapy: A case report

BACKGROUND Cancer of unknown primary (CUP) is a histological proven malignant tumor whose origin cannot be detected despite careful examination. Most cervical lymph node metastases in CUP (80%) will originate from head and neck sites, and 15% show infiltration of squamous carcinoma cells. The survival rates of CUP are poor: The 5-year-survival rate ranges from 10% to 15%. First-line treatment recommendation for advanced, inoperable squamous cell carcinoma of head/neck (HNSCC) was cetuximab plus platinum-fluorouracil chemotherapy until recently, when checkpoint inhibitors proved clinically beneficial therapies. CASE SUMMARY Here, we report a case of a 42-year-old female patient with cervical and abdominal lymph node and distant bone metastases of an occult primary of the head and neck (squamous cell carcinoma, human papillomavirus positive). The cancer was diagnosed during pregnancy 10 years ago, and after giving birth, the patient was treated with cetuximab plus platinum-fluorouracil chemotherapy achieving complete remission (CR). CR lasted 26 mo when new metastases (abdominal lymph node, lumbar vertebral body) emerged. Both manifestations were irradiated. From then on, the patient has not received any further treatment, and her disease has remained controlled. Ten years after the initial cancer diagnosis, the patient is still alive and in good health, representing an exceptional case of HNSCC. CONCLUSION This case illustrates the exceptional clinical course and benefits of combined therapy approaches in advanced metastatic HNSCC with occult primary.