Helical tomotherapy with simultaneous integrated boost dose painting for the treatment of synchronous primary cancers involving the head and neck

Abstract

Objective: To demonstrate the feasibility of helical tomotherapy (HT)-based intensity-modulated radiotherapy (IMRT) for the treatment of synchronous primary cancers arising from the head and neck.

Methods: 14 consecutive patients with histologically proven squamous cell carcinoma of the head and neck were determined to have a second primary cancer in the upper aerodigestive tract on further evaluation and were treated with HT using simultaneous integrated boost IMRT. Megavoltage CT scans were acquired daily as part of an image-guided registration protocol. Concurrent platinum-based systemic therapy was given to nine patients (64%).

Results: HT resulted in durable local control in 21 of the 28 primary disease sites irradiated, including a complete clinical and radiographic response initially observed at 17 of the 20 sites with gross tumour. The mean displacements to account for interfraction motion were 2.44 ± 1.25, 2.92 ± 1.09 and 2.31 ± 1.70 mm for the medial-lateral (ML), superior-inferior (SI) and anteroposterior (AP) directions, respectively. Table shifts of >3 mm occurred in 19%, 20% and 22% of the ML, SI and AP directions, respectively. The 2-year estimates of overall survival, local-regional control and progression-free survival were 58%, 73% and 60%, respectively.

Conclusion: The effectiveness of HT for the treatment of synchronous primary cancers of the head and neck was demonstrated.

Advances in knowledge: HT is a feasible option for synchronous primary cancers of the head and neck and can result in long-term disease control with acceptable toxicity in appropriately selected patients.

Figure 1.

A case illustration of a 79-year-old female who presented to her dentist with a 3-month history of oral pain and was found to have a left retromolar trigone mass. Biopsy revealed poorly differentiated squamous cell carcinoma, and on routine panendoscopy under anaesthesia, a second primary cancer (also biopsy-proven squamous cell carcinoma) was identified in the cervical oesophagus. 18-fludeoxyglucose positron emission tomography/CT confirmed the presence of two primary cancers: (a) an oral cavity cancer (T4N0) originating from the left retromolar trigone with adjacent bony sclerosis with maximum standardized uptake value (SUV) of 6.2 and (b) an oesophagus cancer (T2N) located posterior to the cricoid and extending inferiorly with maximum SUV of 11.4. The patient opted for definitive radiation therapy to address both primary cancers and had a complete clinical response at both sites. Unfortunately, she developed widespread lung metastasis approximately 6 months after the completion of treatment.

Figure 2.

Illustrative helical tomotherapy treatment plan for patient from Figure 1a demonstrating representative (a) axial and (b) sagittal views. The retromolar trigone tumour was irradiated to a dose of 6996 cGy in 33 fractions, with the oesophageal tumour receiving a lower dose of 6000 cGy simultaneously. The prescribed dose to the ipsilateral and contralateral cervical neck was 5940 and 5400 cGy, respectively.

Figure 3.

A case illustration of a 65-year-old male who was status post-bilateral tonsillectomy for T1N0 squamous cell carcinoma involving both right and left tonsils. Surgical pathology revealed positive microscopic margins bilaterally, and the patient opted for post-operative radiation therapy with concurrent cisplatin. The representative helical tomotherapy treatment plans in the (a) axial and (b) coronal views demonstrate the delivery of 6600 cGy in 33 fractions to the bilateral tonsillar beds. Areas at high risk for microscopic disease involvement, including the bilateral cervical neck and retropharyngeal lymph nodes, received a dose of 5940 cGy, and the low neck (supraclavicular fossa) received a dose of 5400 cGy, with treatment delivered simultaneously. A, anterior; P, posterior.

Figure 4.

A case illustration of a 70-year-old male who presented with a 3-month history of hoarseness and was diagnosed with T3N0 squamous cell carcinoma of the glottic larynx. On positron emission tomography/CT (a), a second primary cancer was detected in the cervical oesophagus, with biopsy confirming squamous cell carcinoma. The maximum standardized uptake value for the larynx and oesophageal cancers were 9.5 and 15.5, respectively. The patient opted for definitive radiation therapy with concurrent carboplatin and paclitaxel. The representative helical tomotherapy treatment plans in (b) coronal view demonstrate the delivery of 6996 cGy in 33 fractions to the larynx cancer with a lesser dose of 5600 cGy to the oesophageal cancer and adjacent lymph nodes. All treatment was delivered simultaneously in 33 fractions.