Abstract
Radiotherapy with high doses per fraction may have the potential to control radioresistant tumors, such as malignant melanoma. Here we report 2 cases with malignant melanoma of the nasal cavity treated with hypofractionated stereotactic radiotherapy using CyberKnife®.
1
Introduction
Head and neck malignant melanoma (HNMM) is rare and carries a poor prognosis. Most HNMMs are diagnosed at a late stage because the disease progresses rapidly without symptoms. For advanced disease, surgery with or without adjuvant therapy was considered . However, surgical procedures for advanced disease have a negative impact on patients, because of extensive surgeries, cosmetic problems, and loss of normal function, and high local recurrence rates . Definitive radiotherapy is administered only for few patients because malignant melanoma generally shows a high resistance to radiotherapy . High doses per fraction may have the potential to control radioresistant tumors; however, such high doses are generally toxic to late-responding tissues, such as the brain stem and optic nerve. Recently, the CyberKnife® (Accuray, Sunnyvale, California, USA), a new device that combines a robotic arm with a linear accelerator, has been developed for stereotactic radiotherapy (SRT). This device may provide a method of administering an adequate dose to the tumor while decreasing the dose to the surrounding normal tissue. Here we report on 2 cases (3 lesions) of malignant melanoma of the nasal cavity treated with hypofractionated SRT using CyberKnife®. All data were collected after the approval of an institutional review board.
2
Case reports
2.1
Case 1
A 60-year-old male presented to a local clinic with hemoptysis. At presentation, magnetic resonance imaging (MRI) revealed a mass of 2.3 cm × 4.3 cm × 3.5 cm filling the nasal cavity and the frontal, sphenoid, maxillary, and ethmoid sinuses. Extraocular muscles were compressed by the tumor, causing diplopia ( Fig. 1 ). F-18 fluorodeoxyglucose positron-emission tomography (FDG-PET) showed abnormal accumulation in the tumor as well as internal jugular lymph nodes. The biopsy confirmed the diagnosis of malignant melanoma; he was diagnosed with cT4aN1M0, stage IVa malignant melanoma of the nasal cavity. Carbon-ion radiotherapy was not indicated because of nodal involvement. Radical surgery was considered unsuitable because of the wide and infiltrative nature of the tumor. Neck dissection was performed for lymph node metastasis, and hypofractionated SRT with CyberKnife® was administered for the primary tumor. A total dose of 39 Gy in 8 fractions was administered and no acute adverse events were observed. Postoperative evaluation revealed 1 positive lymph node among 31 resected lymph nodes. One week after radiotherapy, diplopia improved. The patient received combination chemotherapy consisting of cisplatin, dacarbazine, nimustine, and tamoxifen for a single course. A follow-up CT performed 38 months after initial radiotherapy demonstrated a growing mass in the patient’s right maxillary sinus. Biopsy from the maxillary sinus mass confirmed the diagnosis of malignant melanoma; thus, a diagnosis of recurrent malignant melanoma was made. SRT was administered again with a total dose of 35 Gy in 5 fractions using CyberKnife® ( Fig. 1 ). The patient has not had any adverse events and has shown complete response of disease 51 months after the initial radiotherapy and 11 months after the second radiotherapy ( Fig. 2 ).
2.2
Case 2
A 76-year-old male presented to a local hospital with a complaint of prolonged nasal congestion. At presentation, endoscopy found a melanomic mass filling the right nasal cavity. Biopsy of the mass confirmed the diagnosis of malignant melanoma. Computed tomography (CT) and MRI revealed no evidence of the invasion of the surrounding structures or lymph node metastasis. In addition, FDG-PET showed no evidence of distant metastasis. As a result, the patient was diagnosed with cT3N0M0, stage III malignant melanoma of the nasal cavity. Treatment options were discussed by the cancer board; it was concluded that extensive surgery was too invasive for this patient because of his age, and the decision was made to administer SRT using CyberKnife®. Patient refused to receive carbon-ion radiotherapy because of financial problem. A total dose of 35 Gy in 5 fractions was administered, and no acute adverse events were observed. The patient refused any adjuvant therapy. Twelve months after treatment, the patient developed lymph node metastasis, but the local tumor remained stable disease, with disappearance of abnormal FDG uptake by positron emission tomography. The patient is alive with lymph node metastasis.
2
Case reports
2.1
Case 1
A 60-year-old male presented to a local clinic with hemoptysis. At presentation, magnetic resonance imaging (MRI) revealed a mass of 2.3 cm × 4.3 cm × 3.5 cm filling the nasal cavity and the frontal, sphenoid, maxillary, and ethmoid sinuses. Extraocular muscles were compressed by the tumor, causing diplopia ( Fig. 1 ). F-18 fluorodeoxyglucose positron-emission tomography (FDG-PET) showed abnormal accumulation in the tumor as well as internal jugular lymph nodes. The biopsy confirmed the diagnosis of malignant melanoma; he was diagnosed with cT4aN1M0, stage IVa malignant melanoma of the nasal cavity. Carbon-ion radiotherapy was not indicated because of nodal involvement. Radical surgery was considered unsuitable because of the wide and infiltrative nature of the tumor. Neck dissection was performed for lymph node metastasis, and hypofractionated SRT with CyberKnife® was administered for the primary tumor. A total dose of 39 Gy in 8 fractions was administered and no acute adverse events were observed. Postoperative evaluation revealed 1 positive lymph node among 31 resected lymph nodes. One week after radiotherapy, diplopia improved. The patient received combination chemotherapy consisting of cisplatin, dacarbazine, nimustine, and tamoxifen for a single course. A follow-up CT performed 38 months after initial radiotherapy demonstrated a growing mass in the patient’s right maxillary sinus. Biopsy from the maxillary sinus mass confirmed the diagnosis of malignant melanoma; thus, a diagnosis of recurrent malignant melanoma was made. SRT was administered again with a total dose of 35 Gy in 5 fractions using CyberKnife® ( Fig. 1 ). The patient has not had any adverse events and has shown complete response of disease 51 months after the initial radiotherapy and 11 months after the second radiotherapy ( Fig. 2 ).
