Phase II study: Induction chemotherapy & transoral surgery as definitive tx for locally advanced oropharyngeal squamous cell carcinoma (OPSCC)—A novel approach.

Abstract

6078 Background: The standard of care for OPSCC includes chemoradiation (CRT) or surgery with adjuvant radiation (RT). However, RT is associated with significant life long morbidity. We assessed the efficacy of a two-drug induction regimen, followed by transoral robotic assisted surgery (TORS) & neck dissection for locally advanced OPSCC. Methods: This is an IRB approved single-arm phase II study for untreated stage III or IVA OPSCC patients (pts) with an ECOG < 2 and GFR > 50 cc. Induction chemotherapy consisted of cisplatin 75 mg/m2 and taxotere 75 mg/m2 every 21 days for 3 cycles. Tumor shrinkage was examined after each cycle. If the primary tumor was > 80% smaller, pts underwent TORS and neck dissection(s). At post-op visits, flexible laryngoscopy, blood work, and imaging with PET/CT and/or MRI were done. Short and long term toxicity, progression-free survival (PFS) and overall survival (OS), and quality of life (QOL) were evaluated. Results: Nineteenpts were treated and 14 are available for analysis. Thirteen were male, 12 were Caucasian, 2 were African-American, and 13 were HPV+. Median age at diagnosis was 57. Tumors involved the tonsil (11 pts) and base of tongue (3 pts). Three pts were stage III, and 11 were stage IVA. Tumor size was reduced on average by 58%, 84% and 92% after the 1st, 2nd and 3rd induction cycles respectively. Pathologic complete remission of primary disease occurred in 11 pts and in 7 pts with cervical lymph node disease. Four pts were given dose-reduced chemo and one pt was changed to carboplatin per protocol because of renal dysfunction. In addition, adverse events included three patients with grade I fatigue, neuropathy or nausea. Pre vs post tx QOL scores were not significantly different. At a mean follow-up (f/u) of 13 months (range 2.5 to 19.7), 13 pts are alive and well. Three pts recurred, and were treated with salvage CRT. One pt died of metastatic disease. Conclusions: Cisplatin + Taxotere is an effective induction tx for OPSCC, Induction tx followed by transoral & neck resections without RT is a promising tx model for OPSCC. It appears effective while avoiding adverse effects of RT. Longer f/u is required to assess its true efficacy. Clinical trial information: NCT02760667.