Reduced-Dose Intensity-Modulated Radiation Therapy With or Without Cisplatin in Treating Patients With Advanced Oropharyngeal Cancer

Inclusion Criteria

Step 1: Registration:

• Pathologically (histologically or cytologically) proven diagnosis of squamous cell carcinoma (including the histological variants papillary squamous cell carcinoma and basaloid squamous cell carcinoma) of the oropharynx (tonsil, base of tongue, soft palate, or oropharyngeal walls); cytologic diagnosis from a cervical lymph node is sufficient in the presence of clinical evidence of a primary tumor in the oropharynx. Clinical evidence should be documented, may consist of palpation, imaging, or endoscopic evaluation, and should be sufficient to estimate the size of the primary (for T stage).
• Patients must have clinically or radiographically evident measurable disease at the primary site or at nodal stations. Tonsillectomy or local excision of the primary without removal of nodal disease is permitted, as is excision removing gross nodal disease but with intact primary site. Limited neck dissections retrieving ≤ 4 nodes are permitted and considered as non-therapeutic nodal excisions.
• Immunohistochemical staining for p16 must be performed on tissue, and this tissue must be submitted for central review. Fine needle aspiration (FNA) biopsy specimens may be used as the sole diagnostic tissue if formalin-fixed paraffin-embedded cell block material is available for p16 immunohistochemistry. FNA specimens prepared with adequate p16 testing in this manner are acceptable to submit for central review. If the p16 preparation is not adequate, additional specimens will be required to establish p16 status. Centers are encouraged to contact the pathology chairs for clarification.
• Clinical stage T1-T2, N1-N2b or T3, N0-N2b (AJCC, 7th ed.) including no distant metastases based on the following diagnostic workup:
• General history and physical examination within 56 days prior to registration;
• Fiberoptic exam with laryngopharyngoscopy (mirror and/or fiberoptic and/or direct procedure) within 70 days prior to registration;
• One of the following combinations of imaging is required within 56 days prior to registration:
• A computed tomography (CT) scan of the neck (with contrast) and a chest CT scan (with or without contrast);
• or an MRI of the neck (with contrast) and a chest CT scan (with or without contrast);
• or a CT scan of neck (with contrast) and a PET/CT of neck and chest (with or without contrast);
• or an MRI of the neck (with contrast) and a PET/CT of neck and chest (with or without contrast).

Note: A CT scan of neck and/or a PET/CT performed for the purposes of radiation planning may serve as both staging and planning tools.

• Patients must provide their personal smoking history prior to registration. The lifetime cumulative history cannot exceed 10 pack-years. The following formula is used to calculate the pack-years during the periods of smoking in the patient's life; the cumulative total of the number of pack-years during each period of active smoking is the lifetime cumulative history.

Number of pack-years = [Frequency of smoking (number of cigarettes per day) × duration of cigarette smoking (years)] / 20

Note: Twenty cigarettes is considered equivalent to one pack. The effect of non-cigarette tobacco products on the survival of patients with p16-positive oropharyngeal cancers is undefined. While there are reportedly increased risks of head and neck cancer associated with sustained heavy cigar and pipe use (Wyss 2013), such sustained use of non-cigarette products is unusual and does not appear to convey added risk with synchronous cigarette smoking. Cigar and pipe tobacco consumption is therefore not included in calculating the lifetime pack-years. Marijuana consumption is likewise not considered in this calculation. There is no clear scientific evidence regarding the role of chewing tobacco-containing products in this disease, although this is possibly more concerning given the proximity of the oral cavity and oropharynx. In any case, investigators are discouraged fro