Cancers of the soft palate and pharyngeal wall are less common than other oropharyngeal neoplasms. Most soft-palate cancers occur on the anterior surface of the palate and tend to be superficial. Regional metastases are uncommon, although lateral extension to the tonsillar area results in an increased rate of lymph node involvement and lesions close to the midline can result in bilateral or contralateral neck metastases in 15% of patients. Occult node metastases are estimated to occur in 16% of patients. Posterior wall lesions tend to be superficial with less tumor bulk than similarly staged lesions elsewhere in the oropharynx.
Tumor extension to the tongue base decreases survival and increases the rate of metastases, which are often bilateral. Advanced lesions with deep invasion have ready access to the prevertebral space, infratemporal fossa, and skull base and can be associated with extensive submucosal spread with clinical skip areas.
Radiation alone as curative treatment is preferred in most cases, even for T3 or T4 primary tumors. Resection of all but the smallest soft-palate lesions is associated with severe functional disability. The rates of occult regional metastases are difficult to determine because elective irradiation of bilateral nodal groups is included as part of primary treatment and must include the retropharyngeal lymphatics. Clinically positive lymph nodes at presentation occur in 30% of patients.
Small primary tumors with positive nodes can be effectively treated with definitive radiation to the primary tumor and neck. Neck dissections should be performed if disease in the neck persists for 6 to 8 weeks following the completion of external beam therapy. Extensive pharyngeal wall cancers or palate cancers with extension to the tonsil and those cases with advanced regional metastases are usually treated with combined surgical resection and postoperative radiation. Overall 5-year survival rates for soft-palate and faucial pillar cancers are 60% to 70% and range from 80% to 90% for T1 and T2 lesions to 30% to 60% for stages III and IV lesions. Locoregional recurrence is the most frequent cause of failure. For advanced lesions, concomitant chemoradiotherapy in IRB-reviewed protocols is recommended (see “Chemo- therapy,” below).
Revision date: July 4, 2011
Last revised: by Janet A. Staessen, MD, PhD