From the Guidelines
The cure rate for p16 positive oropharyngeal cancer treated with definitive chemoradiation is approximately 80-90%, which is significantly better than p16 negative disease. Standard definitive chemoradiation typically involves intensity-modulated radiation therapy (IMRT) delivered at 70 Gy over 7 weeks (2 Gy per fraction) with concurrent cisplatin chemotherapy, usually given at 100 mg/m² every 3 weeks for 3 cycles or 40 mg/m² weekly for 7 weeks, as supported by high-quality evidence from recent studies 1. The improved outcomes for p16 positive disease (which is typically HPV-related) reflect its distinct biology and better response to treatment compared to tobacco/alcohol-related oropharyngeal cancers.
Some key points to consider in the management of p16 positive oropharyngeal cancer include:
- The use of concurrent high-dose intermittent cisplatin with definitive radiotherapy is recommended for stage IVA-IVB disease, based on high-quality evidence and strong recommendations 1.
- De-intensification strategies are being investigated in clinical trials to potentially reduce treatment-related toxicities while maintaining high cure rates, with some studies suggesting reduced elective nodal irradiation (ENI) volumes or omission of contralateral lymph nodes 1.
- Patients should be closely monitored during treatment for management of acute toxicities including mucositis, dermatitis, dysphagia, and xerostomia.
- Following treatment, regular surveillance is necessary with physical examinations and imaging for at least 5 years.
- The role of induction chemotherapy is not recommended outside of a laryngeal-preservation strategy, and the standard regimen is concomitant chemoradiation therapy (CRT) with high-dose cisplatin when a non-surgical approach is preferred, as supported by recent guidelines 1.
Overall, the management of p16 positive oropharyngeal cancer requires careful consideration of the patient's individual needs and circumstances, as well as ongoing monitoring and evaluation to optimize treatment outcomes and minimize toxicity.
From the Research
Cure Rate with Definitive Chemoradiation for p16 Positive Oropharyngeal Cancer
- The cure rate for p16 positive oropharyngeal cancer with definitive chemoradiation is a topic of ongoing research, with various studies comparing the efficacy of different chemoradiation regimens 2, 3, 4.
- A study published in the Lancet in 2019 found that radiotherapy plus cisplatin resulted in a higher 5-year overall survival rate (84.6%) compared to radiotherapy plus cetuximab (77.9%) for patients with HPV-positive oropharyngeal cancer 2.
- Another study published in Oral Oncology in 2018 found that cisplatin improved 3-year locoregional control, distant metastasis-free survival, recurrence-free survival, and overall survival compared to cetuximab for patients with p16 positive oropharyngeal cancer 3.
- A retrospective review published in Reports of Practical Oncology and Radiotherapy in 2018 found that cisplatin-based chemoradiotherapy resulted in better outcomes compared to cetuximab-based bioradiotherapy for patients with p16 positive oropharyngeal squamous cell carcinoma, particularly for those with stage III disease 4.
- A study published in Oral Oncology in 2018 found that induction chemotherapy followed by concurrent chemoradiation may reduce the risk of distant failure and improve progression-free survival for patients with p16 positive oropharyngeal squamous cell carcinoma with low-neck or N3 disease 5.
Comparison of Chemoradiation Regimens
- Cisplatin-based chemoradiotherapy has been shown to be more effective than cetuximab-based bioradiotherapy for patients with p16 positive oropharyngeal cancer, particularly for those with stage III disease 3, 4.
- The addition of induction chemotherapy to concurrent chemoradiation may improve outcomes for patients with p16 positive oropharyngeal cancer at high risk of distant failure 5.
- Radiotherapy plus cisplatin has been shown to result in a higher 5-year overall survival rate compared to radiotherapy plus cetuximab for patients with HPV-positive oropharyngeal cancer 2.
Prognostic Factors
- p16 status has been shown to be a prognostic factor for patients with oropharyngeal cancer, with p16 positive patients having a better prognosis 6.
- The use of cisplatin-based chemoradiotherapy has been shown to improve outcomes for patients with p16 positive oropharyngeal cancer, particularly for those with stage III disease 3, 4.