Management of tonsillar carcinoma with advanced radiation therapy and chemotherapy techniques

Case 3

A 53-year-old white man, who had no smoking or tobacco history but who was exposed to chemicals including sulfuric acid, hydrogen chloride gas, and glycols at work, presented initially with a sore throat that became more painful over time. His ENT specialist referred him for a CT scan of the neck, which revealed a left-sided neck mass measuring 2.5 cm in diameter posterior to the submandibular gland and lateral to carotid sheath and anterior to the triangle (Figure 2, Case 3). The mass appeared to be encapsulated. There was a lobulated spherical mass in the left supraglottic area with formation of the airway of the pyriform sinus and additional anterior vascular involvement was noted. The mass measured 3.6 cm in transverse diameter.

A left tonsillar biopsy specimen measuring 1.4 x 0.6 x 0.2 cm was obtained, and its pathology revealed that the patient had a metastatic squamous cell carcinoma. The left neck lymph node mass aspiration also revealed the presence of squamous cell carcinoma. A PET-CT scan staging showed a dominant tonsillar fossa mass extending from the soft palate down to the pyriform sinus measuring 4.2 x 3.8 cm, with an SUV uptake of 7.3. There was a dominant left level II necrotic lymph node presence measuring 5.0 x 3.7 cm, with an SUV of 3.0. The patient’s Karnofsky performance status was 90%. The tumor stage was T4N2M0, a stage IVa disease. The patient received a course of conformal hyperfractionated IMRT-IGRT delivered to the primary tumor in 67 fractions at 120 cGy twice daily for a total dose of 8,040 cGy¹⁶ and concurrent carboplatin chemotherapy at a weekly dose of 200 mg.

After completion of his radiation therapy, chemotherapy was changed based on genomic testing from single agent to doublet with carboplatin (area under the curve (AUC) dose of 2 or 200 mg, weekly) plus docetaxel (25 mg/m² weekly for 3 weeks and 1 week off ).^17,18 A PET scan after chemoradiation therapy revealed a marked anatomical improvement in the primary neoplastic disease seen in the faucial tonsil. The tonsillar mass noted previously had almost completely resolved over the interval, with only a mild persistent asymmetrical thickening of around 1.5 cm, with a peak SUV of 2.0. A lymph node of 2.8 x 2.0 cm was present anterior to the left sternocleidomastoid muscle exhibiting SUV of only 1.8. No other abnormal lesions were noted (Figure 2, Case 3). The patient continues to do extremely well without local recurrence of the disease 46 months after radiation therapy (see Table for patient demographics, tumor characteristics, and therapy details.)
 

Discussion

The management of patients with primary squamous cell carcinoma of the oropharyngeal remains controversial. Traditionally, early-stage tonsillar squamous cell carcinoma was managed by a single modality treatment, either by surgery or radiation therapy, each showing similar efficacy and outcomes.¹⁹ For late-stage disease, a combined approach using surgery and radiation therapy was found to be superior to single modality treatment. However, surgery in conjugation with radiation therapy has been associated with significant toxicities compared with the radiation therapy alone.¹³Therefore, the use of radiation therapy without surgery is becoming more common with increasingly sophisticated radiation therapy techniques and organ preservation approach in patients with squamous cell carcinoma of the tonsil.

Findings from several studies have shown that in stage I or II oropharyngeal cancer, single modality treatment with radiation therapy achieves 80%-90% of local control of the disease, but poorer outcomes are reported for locally advanced stages III/IV with a local control rate of 63%-74%.²⁰ These findings and others have led to a shift to evaluate the clinical benefits of radiation therapy given with concurrent chemotherapy for the primary treatment of advanced stage oropharyngeal squamous cell carcinoma.^20,21 Findings from a number of studies have since reported comparable efficacy and toxicity outcomes using this regimen with concurrent chemotherapy in patients with locally advanced head and neck squamous cell cancer.^22-24 Synchronous carboplatin chemotherapy was used effectively as an alternative to cisplatin with fewer potential adverse effects in the good prognosis group of patients with oropharyngeal squamous cell carcinoma.^25,26 For our 3 patients, we used carboplatin-based chemotherapy with concurrent advanced hyperfractionated radiation therapy techniques to successfully manage tonsillar squamous cell carcinoma and reduce renal toxicity and neuropathy.

Advanced radiation therapy techniques such as IMRT-IGRT are used routinely at the University Cancer and Diagnostic Centers in Houston, Texas, to manage a range of malignant cancers.²⁷ These innovative techniques have the potential to deliver highly conformal dose-intense radiation to targeted regions of disease, while sparing adjacent critical nonmalignant tissue. The improved shaping of high-dose distributions with IMRT-IGRT could mitigate treatment-related toxicities. For example, the use of advanced radiation therapy techniques has been associated with increased preservation of parotid salivary flow.^28-30 The use of advanced radiation therapy techniques in head and neck squamous cell carcinoma is growing, and early evidence confirms its ability to secure excellent local and regional disease control.^31,32 In this study, we have demonstrated that by using hyperfractionated conformal three-dimensional IMRT-IGRT we were able not only to manage advanced tonsillar squamous cell carcinoma and treat the malignant metastasis, but also spare adjacent critical organs that were not involved in the disease, thus reducing many of the detrimental side effects associated with hyperfractionated chemoradiation.

All 3 patients were followed for between 40 and 46 months. They continue to do extremely well without local recurrence of their disease, indicating a 100% disease control and overall survival rate. The disease control and survival outcomes for our patients with stage IVA disease compare favorably to other published reports in the literature.^33,34 Findings from a study by Prestwich and colleagues³³ of 41 patients with stage IV tonsillar carcinoma showed that the radiation therapy with concurrent chemotherapy achieved local and regional disease control in 91% of complete responders and an overall survival rate of 66% at 3 years. Similarly, Setton and colleagues³⁴ reported on 442 patients – 50% with tonsillar cancer, 46% with base-of-tongue cancer – who underwent IMRT and concurrent chemotherapy and who achieved a 3-year overall survival of 84.9%. Our study findings demonstrate that hyperfractionated conformal three-dimensional IMRT-IGRT with concurrent chemotherapy can be delivered safely and effectively to patients with advanced tonsillar squamous cell carcinoma.