Late Breaking Abstract – ASCO 2022: Docetaxel as Radiosensitizer Improves Overall Survival in Cisplatin-Ineligible Head and Neck cancer

SUMMARY: The American Cancer Society estimates that in the US for 2022, about 54,000 new cases of oral cavity or oropharyngeal cancer will be diagnosed and about 11,230 patients will die of the disease. Patients with squamous cell carcinoma of the head and neck, frequently present with locoregionally advanced disease. For patients in this setting, chemoradiotherapy is an effective non-surgical approach as primary treatment. Alternatively, chemoradiotherapy can be delivered as adjuvant therapy after a curative resection.

Cisplatin-based concurrent chemoradiation is generally accepted as the standard, definitive non-surgical and post-operative approach in selected patients with locoregionally advanced squamous cell carcinoma of the head and neck. This treatment can however be associated with substantial morbidity and lifelong toxicities. Cetuximab is an immunoglobulin G1 chimeric monoclonal antibody against Epidermal Growth Factor Receptor (EGFR), and the only approved targeted agent in locoregionally advanced squamous cell carcinoma of the head and neck. Cetuximab plus Radiotherapy significantly improved Overall Survival at 5 years, when compared with radiotherapy alone, in patients with locoregionally advanced squamous cell carcinoma of the head and neck (Lancet Oncol. 2010). Cetuximab plus Radiotherapy is therefore an important treatment option in this patient group. However, financial barriers make Cetuximab as a Cisplatin substitute, inaccessible to patients, in low and middle-income countries.

Docetaxel is a semisynthetic taxane that affects polymerized tubulin to promote microtubule formation and inhibit its disassembly. Docetaxel has been shown to have significant antitumor activity as a single agent in head and neck cancer, when given in the neoadjuvant setting. Docetaxel is also a potent radiosensitizer. The researchers evaluated Docetaxel as a radiosensitizer in this clinical trial.

The authors in this open-label, randomized, Phase III study enrolled 356 Cisplatin-ineligible patients with locally advanced head and neck squamous cell carcinoma, planned for treatment with radical or adjuvant chemoradiation. The patients were randomly assigned 1:1 to receive Radiation alone (N=176) or Radiation with concurrent Docetaxel 15 mg/m2 IV weekly for a maximum of 7 cycles (N=180). Both treatment groups were well balanced. The median age was 62 yrs, approximately 45% of patients had a ECOG Performance Status of 2, and reasons for Cisplatin ineligibility included low creatinine clearance (26%), and hearing loss (43%). Approximately 33% of patients had oral cavity cancer and about two-thirds of patients had Stage IVA disease. The FACT-G, and Head and Neck questionnaires were completed by patients at baseline, 6 months, 12 months and at 24 months. FACT-G (Functional Assessment of Cancer Therapy-G) is a 27-item questionnaire designed to measure four domains of Health-Related Quality of Life (HRQOL) in cancer patients, which includes physical, social, emotional, and functional well-being. The Primary endpoint was Disease Free Survival (DFS), and key Secondary endpoints included Overall Survival (OS), adverse events and Quality of Life.

It was noted that the 2-year DFS was 30.3% with Radiation alone versus 42% with Docetaxel plus Radiation Therapy (HR=0.67; P=0.002). Docetaxel plus Radiation Therapy also significantly improved Overall Survival. The median Overall Survival was 15.3 months with Radiation Therapy alone, versus 25.5 months in the Docetaxel plus Radiation Therapy group (P=0.035). The 2 -year Overall Survival was also significantly higher in the Docetaxel plus Radiation Therapy group and was 41.7% with Radiation Therapy alone, versus 50.8% in the Docetaxel plus Radiation Therapy group (HR=0.74; P=0.035). These survival outcomes were observed across all preplanned subgroups.

Grade 3 or above adverse events were seen in 58% of patients receiving Radiation Therapy alone and in 81.6% of patients receiving Docetaxel plus Radiation Therapy. The addition of Docetaxel to Radiation Therapy resulted in a higher incidence of Grade 3 and above mucositis (49.7% versus 22.2%; P<0.001), odynophagia (52.5% versus 33.5%; P<0.001) and dysphagia (49.7% versus 33%; P<0.002). The addition of Docetaxel however did not lead to a worsening of Quality of Life, including Trial Outcome Index and FACT-G scores at 6 months.

The authors concluded that the addition of Docetaxel to Radiation Therapy improved Disease Free Survival and Overall Survival, in Cisplatin-ineligible locally advanced head and neck squamous cell carcinoma, and provides an evidence based, financially more viable treatment option, for this patient group.

Results of phase 3 randomized trial for use of docetaxel as a radiosensitizer in patients with head and neck cancer unsuitable for cisplatin-based chemoradiation. Patil VM, Noronha V, Menon NS, et al. DOI: 10.1200/JCO.2022.40.17_suppl.LBA6003 Journal of Clinical Oncology 40, no. 17_suppl (June 10, 2022) LBA6003.