The purpose of this study is to determine whether treatment of HPV-related oropharyngeal squamous cell carcinoma in patients with undetectable postoperative HPV circulating tumor DNA (cfHPVDNA) with transoral robotic surgery (TORS) alone can result in cancer control and survival comparable to those previously reported with standard therapy. The protocol includes patients with only with low or intermediate pathologic risk factors following surgery with detectable pre-surgery cfHPVDNA and undetectable post-surgery cfHPVDNA.

The hope is that with this approach, the long-term complications from chemotherapy and radiation can be reduced.

There has been significant increase in the incidence of oropharynx cancer in North America and Europe. It is now understood that there are two dominant carcinogenic pathways for oropharyngeal squamous cell carcinoma. Environmentally related which is caused mainly by smoking and alcohol, and HPV-related oropharyngeal squamous cell carcinoma (HPVOPSCC). HPVOPSCC now accounts for over 80% of OPC seen in the USA and an increasing fraction of these malignancies in Europe. It has been shown that HPVOPSCC confers an excellent prognosis for intermediate staged disease and this has called into question the rational for aggressive concurrent chemoradiotherapy. High-dose radiotherapy (RT) and chemoradiotherapy (CRT) have substantial impact on local tissues and organ function and result in a significant rate of late mortality and morbidity. Studies are now being designed to reduce the impact of RT and CRT for patients.

Recently, a new test has been developed that measures HPV circulating tumor DNA (cfHPVDNA) in the blood. The test has emerged as a promising biomarker for HPVOPSCC, correlating with both treatment response as well as surveillance for cancer recurrence. Data suggests that a negative test in the surveillance period following treatment is highly sensitive and specific for recurrent disease.

In this trial, the study will be stratifying p16 positive patients with PCR detectable high-risk (HR) HPV DNA or RNA following TORS into risk groups based on final pathology to determine appropriate treatment intensity. Patients with low- or intermediate-risk pathologic disease and undetectable postoperative cfHPVDNA will receive no adjuvant therapy. This group includes patients with AJCC 7th edition T1-T2N0-2b disease. Patients must have less than four pathologic nodes on final pathology, negative margins, and no contralateral nodes. Perineural or lymphovascular alone is allowed but not in combination. Microscopic extranodal extension (less than or equal to 2 mm) is allowed. Patients cannot be active smokers or have a 20 or greater pack year history of smoking.

Inclusion Criteria:

• Patients must have histologically or cytologically confirmed and identified resectable primary OPSCC with positive p16 immunohistochemistry, defined as strong and diffuse nuclear and cytoplasmic staining in > 70% of tumor cells. Immunohistochemistry must be performed or reviewed at the central laboratory. P16 status may be determined prior to consent and must be confirmed by surgical specimen if a biopsy is unavailable. HR-HPV status and postoperative cfHPVDNA testing must be performed and resulted prior to treatment assignment. Tissue from the primary site must be available for biomarker studies after surgery.

• Patients enrolled in the trial must have pre-surgery baseline cfHPVDNA using the NavDX assay (Naveris, Cambridge, MA). Detectable baseline cfHPVDNA copy number is defined as ≥ 10 fragments/mL and is required for inclusion in the trial.

• Undetectable cfHPVDNA after surgery. All patients should have a repeat cfHPVDNA test within 1 to 5 weeks post-operatively and prior to treatment assignment. Undetectable cfHPVDNA is defined as < 5 fragments/mL.

• AJCC 7th edition early and intermediate stage (T1N0-2B, T2N0-2B) (non-matted) disease without evidence of distant metastases or gross extranodal extension.

• Age ≥ 18 years at screening

• No previous surgery, radiation therapy, or chemotherapy for head and neck cancer (other than excision/incisional biopsy of the primary site, excisional/incisional nodal biopsy, or tonsillectomy) is allowed at time of study entry.

• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.

• No active tobacco use (≥1cigarette or cigarette-equivalent per day within the last 5 years) and no cumulative smoking history of >20 pack years. 1 cigar = 4 cigarette-equivalent exposure

• Ability to understand and the willingness to sign a written informed consent document.

• Participants must have adequate bone marrow, hepatic and renal functions as defined below:

  • Platelet count ≥ 90 x 109/l.
  • Hemoglobin ≥ 10 g/dl (may achieve by transfusion).
  • Renal function: eGFR ≥ 50 ml/min

Exclusion Criteria

• Age < 18 years at screening

• Pregnant or breast-feeding women.

• Previous or current malignancies at other sites, except for adequately treated in situ carcinoma of the cervix, basal or squamous cell carcinoma of the skin, thyroid cancer, prostate cancer treated with surgery/radiotherapy, ductal carcinoma in situ of the breast treated with surgery/radiotherapy, or other cancer curatively treated and with no current evidence of disease for at least 3 years.

• Other serious illnesses or medical conditions including but not limited to:

  • Unstable cardiac disease despite treatment or myocardial infarction within 6 months prior to study entry.
  • History of significant neurologic or psychiatric disorders including severe dementia or poorly controlled seizures
  • Active clinically significant uncontrolled infection
  • Active peptic ulcer disease defined as unhealed or clinically active
  • Active drug addiction including alcohol, cocaine or intravenous drug use defined as occurring within the 6 months preceding diagnosis
  • Severe chronic obstructive pulmonary disease, defined as being associated with a hospitalization for pneumonia within 12 months of diagnosis.
  • Prior organ transplant
  • Interstitial lung disease
  • Concurrent treatment with any other anti-cancer therapy
  • Participation in an investigational therapeutic drug trial within 30 days of study entry. Participation in additional investigational radiation studies will exclude participation in SIRS. Participation in non-therapeutic, non-oncologic investigational studies (i.e. pain control studies, nutritional studies, etc.) will be allowed amongst SIRS participants, provided there is no alteration of treatment planning, oncologic therapy, or surveillance, and additional studies comply with SIRS safety criteria and stopping rules as outlined in the SIRS protocol.
  • Active hepatitis C by history

• Advanced nodal stage (AJCC 7th edition N2C, N3) or surgically unresectable disease or disease that cannot be fully resected, unequivocal radiographic extranodal extension, unequivocal radiographic or clinical supraclavicular or matted metastatic disease, > 3 unequivocally radiographic pathologic cervical nodes.

• Non-HR-HPV subtype on initial biopsy or final pathology.

• 5 or more positive nodes, irrespective of size, on final pathology.

• p16 or HPV negative OPSCC as determined by IHC and PCR or ISH, respectively.

• Undetectable or < 10 fragments/mL baseline cfHPVDNA prior to surgery.

• Autoimmune disease treated with chemotherapy agents or anti TNF agents within the last 2 years.

• Detectable repeat cfHPVDNA 1-5 weeks postoperatively via the NavDX assay, defined as > 5 fragments/mL.

All of the individual participant data collected during the trial, after deidentification.

Immediately following publication. No end date.