Head and Neck Oncology and CNS Tumors
What this domain tests
This domain pairs mucosal head and neck cancer - where radiotherapy technique, chemotherapy radiosensitization and HPV status decide outcomes - with CNS tumors, where molecular classification, the Stupp paradigm and the management of brain metastases are the recurring themes.
Core rules
- Head and neck: HPV-positive oropharyngeal cancer has a distinct staging system and better prognosis. Definitive radiotherapy is 70 Gy in 35 fractions with concurrent cisplatin 100 mg/m² every three weeks; weekly cisplatin 40 mg/m² is an alternative with less certain equivalence. Postoperative radiotherapy indications include positive margins, extranodal extension, pT3/T4, perineural invasion and multiple nodes; add concurrent cisplatin for positive margins or extranodal extension.
- Larynx preservation: concurrent chemoradiation offers equivalent survival to total laryngectomy in selected T3 disease (RTOG 91-11), with concurrent cisplatin outperforming induction chemotherapy or radiotherapy alone.
- Recurrent/metastatic HNSCC: pembrolizumab alone or with platinum and 5-FU when PD-L1 CPS ≥1 (KEYNOTE-048).
- Nasopharynx: EBV-associated; treat with induction chemotherapy followed by chemoradiation in locoregionally advanced disease.
- Gliomas: integrate histology with IDH status, 1p/19q codeletion and MGMT promoter methylation. Glioblastoma: maximal safe resection, radiotherapy 60 Gy in 30 fractions with concurrent and adjuvant temozolomide (Stupp), plus tumor-treating fields as an option. IDH-mutant and 1p/19q-codeleted oligodendroglioma has a much better prognosis.
- Brain metastases: stereotactic radiosurgery for limited lesions, whole-brain radiotherapy with hippocampal avoidance and memantine for multiple lesions, and targeted therapy based on primary driver status.
- Primary CNS lymphoma: high-dose methotrexate-based regimens; avoid craniospinal irradiation as initial therapy.
Worked example
A 65-year-old with a resected glioblastoma, MGMT promoter methylated. Standard treatment is radiotherapy 60 Gy in 30 fractions with concurrent temozolomide 75 mg/m² daily, followed by six adjuvant cycles of temozolomide 150–200 mg/m² for five days per 28-day cycle. MGMT methylation predicts greater benefit from temozolomide; it does not change the radiotherapy dose.
Traps
- Waiting to start temozolomide until radiotherapy planning is complete - they start together.
- Prescribing prophylactic anticonvulsants to every brain tumor patient; they are not routine.
- Missing pseudoprogression on the first post-radiotherapy MRI and abandoning effective therapy.
- Applying the HPV-positive staging and prognosis to non-oropharyngeal sites.