Management of tonsillar carcinoma with advanced radiation therapy and chemotherapy techniques

Tonsillar carcinoma is the most common of the oropharyngeal malignancies of the head and neck region after thyroid and laryngeal carcinoma. Squamous cell carcinoma is the most frequent histologic type of these tumors.¹ Tonsillar tumors may originate in the oral cavity, oropharynx, hypopharynx, or larynx. In the United States, more than 5,000 new cases of oropharynx cancer are diagnosed annually.² Men are affected three to four times more often than are women, and the rate of incidence increases after the 4th decade of life.³ Surveillance, Epidemiology, and End Results data from 1975-2004 show that tonsillar squamous cell carcinoma has had one of the largest increases in the male-to-female incidence rate ratios.⁴ The overall incidence of tonsillar carcinoma is increasing, especially in the younger population, and this may be attributed to increasing rates of human papilloma virus.^5,6

Squamous cell carcinoma in the head and neck originate from subsites within the oral cavity, oropharynx, hypopharynx, larynx, and nasopharynx.⁷ Traditionally, alcohol consumption and tobacco use were considered the most significant risk factors for the development of tonsillar cancer.⁸ More recently, however, the high-risk oncogenic human papilloma virus has emerged as a clinical entity in the pathogenesis of squamous cell carcinoma in the head and neck. Other risk factors include poor oral hygiene, mechanical irritation, chewing of betel quid preparations, and a lack of vegetables and fruits in the diet.^9-11 Squamous cell carcinoma of the oropharynx often presents late with lymph node involvement at the time of diagnosis. Nonspecific symptoms such as a sore throat and dysphagia can allow head and neck cancer to evade early detection. Many patients with tonsillar carcinoma present with advanced disease because early lesions are generally asymptomatic when small. This absence of symptoms is responsible for 67%-77% of patients presenting with tumors larger than 2.0 cm and often with regional nodal metastasis. At presentation, 45% of anterior tonsillar pillar lesions and 76% of tonsillar fossa lesions have clinically positive necks.¹²

Despite significant treatment advances, the management of advanced squamous cell carcinoma of the tonsil remains challenging. Historically, surgery was considered the standard of care for patients with tonsillar carcinoma with or without postoperative adjuvant radiotherapy. In locally advanced tonsillar carcinoma, extensive surgery with major tissue reconstruction was necessary, leading to speech dysfunction, cosmetic deformities, and difficulties in swallowing, all of which are detrimental to patient quality of life.¹³ Given the critical role of the oropharynx in speech and swallowing, nonsurgical therapy with organ-preserving chemoradiation has gained a greater role in the treatment of tonsil carcinoma.¹³ Over the past decade, innovations in radiation therapy techniques have led to the introduction of intensity-modulated radiation therapy (IMRT) and image-guided radiation therapy (IGRT) for the treatment of various cancers including tonsillar carcinoma.^14,15 IMRT is an advanced mode of conformal high-precision radiotherapy that uses computer-controlled multiple small radiation beams of varying intensities to deliver precise radiation doses to the target tissues while sparing adjacent healthy tissues.¹⁴ By incorporating three-dimensional computed-tomography (CT) or positron-emission–tomography (PET) imaging technology, IMRT allows the radiation dose to conform more precisely to the three-dimensional shape of the tumor while modulating the intensity of the radiation beam and minimizing its dose to those adjacent sensitive and unaffected organs. IGRT uses a range of two-, three-, and four-dimensional imaging techniques that improve the precision and accuracy of the delivery of the radiation dose to the targeted tumor tissue while minimizing the dose to the surrounding normal tissue during the course of radiation therapy (Figure 1). In this report, we present challenging cases of advanced tonsillar carcinoma and describe our experience in managing the disease using a hyperfractionated IMRT-IGRT based three-dimensional conformal radiation therapy protocol with concurrent chemotherapy.

Case presentations and summaries

Case 1

A 52-year-old white, nonsmoking man who worked in a research chemical laboratory, presented with complaints of throat pain and difficulty in swallowing. The patient had a history of asthma and allergies and had been seen by an ear, nose, and throat (ENT) specialist prior to his visit to our oncology center. A biopsy was performed on a right tonsillar mass measuring 2.7 x 3.6 cm. A computed-tomography (CT) scan showed 2 enlarged inhomogeneous lymph nodes measuring 2.9 cm and 1.7 cm. The nodes were well defined with no soft tissue edema. Neoplasm was favored as a diagnosis and biopsy of the mass was carried out. A biopsy specimen measuring 1.0 x 0.4 x 0.3 cm revealed a moderately differentiated infiltrating squamous cell carcinoma, which extended to the edge of the biopsy specimen. The patient’s Karnofsky performance status was 90% (ie, able to carry on normal activity; minor signs or symptoms of disease).