RADIATION-INDUCED ORPHARYNGEAL CANCER - A LONG-TERM SEQUELAE OF INTRAORAL RADIUM IMPLANT

It is well known that external beam radiotherapy to the head and neck region can come in acute and chronic toxicities. A rare long-term complication of radiation treatment is the radiation-induced malignancies and these are more likely to be met with when external beam radiotherapy is given to the head and neck region in childhood. However the incidence of permanent radium implant induced head and neck malignancy is unknown. We report an unusual case of radium induced oropharyngeal carcinoma which highlights the potentially serious sequelae ol'permanent radium implant left in situ.

Key words: radium, radiation-induced, oropharyngeal neoplasms, next to the first primary neoplasms, head and neck neoplasms

Introduction

Primary head and neck malignancy is usually managed with single modality therapy (surgery or radiotherapy alone) or combined therapy (surgery and radiotherapy with or without adjuvant chemotherapy), depending upon disease, patient and treatment factors. The potential acute and chronic toxicities of radiation therapy to the head and neck region are well known. These include mucositis, xerostomia, radiodermatitis, osteoradionecrosis and carotid stenosis.1,2,3,4 External beam radiation-induced tumours in the head and neck region are rare, accounting for les than 1% of head and neck tumours.5 Skin cancer, thyroid cancer, osteosarcoma, fibrosarcoma and squamous confined apartment carcinoma4,5,6,7,8,9 are amongst the cancers which can be induced by dint of radiation. We report an unusual case of radiation-induced tonsillar squamous confined apartment carcinoma 34 years after intraoral radium semens were implanted for the treatment of previous tongue cancer.

Case Report

A 63 year-old male nursing residence resident with cerebral palsy and rigid kyphoscoliosis was referred to the Otolaryngology Unit in 2003 with several month history of progressive throat pain, dysphagia and extremely poor oral intake secondary to a right-sided clinically T4N0 ulcerating tonsillar squamous small room carcinoma. The patient did not have a history of smoking or alcohol use. He had a past history of right-sided tongue squamous confined apartment carcinoma in 1969 treated with the insertion of 21 radon sperms It is unclear if these radon sperms were subsequently removed. A year later he underwent right neck dissection for the treatment of neck return Hc was subsequently followed up for 7 years without signs of return He was well until several month prior to his popular presentation. Clinically, the patient had an extensive ulcerating tonsillar tumour involving the right-sided impressible palate, posterior buccal mucosa and posterior tongue base.

The patient underwent palliative endoscopic transoral laser debulking of the tumour. sum of two units small metallic foreign bodies (radium implants) were discovered at the inferior portion of the tumour mass within the right tongue base muscle (Figure 1) Histology showed an extensive ulcerated moderately to poorly differentiated squamous small room carcinoma with muscle invasion.

Post-operative retrieval was uneventful. The patient was discharged to the nursing domicile under the care of the palliative care team.

Discussion

Multiple primary head and neck tumours are not exceptional with 8.5 to 40% of cases10,11,12,13,14 place to be complicated by the unfolding of second primary tumours. They can at hand either synchronously or metachronously. The particular oftenness with which multiple primary tumours complicate head and neck tumours supports the field cancerization theory.15 Fields with diameters of above seven centimetres have been described in head and neck mucosa, and these fields oftentimes remain after initial therapy of the index tumour and have been propos to lead to of recent origin cancers.16 A review of literature set the longest recorded time interval between the first primary malignancy and the unravelling of the second malignancy is 28 years.17 The greatest in quantity important risk factors for developing a next to the first head and neck malignancy are still nicotine and alcohol use in excess17 Although the next to the first cancer in this report falls within a seven centimetre range of the initial tumour and its appearance could be consistent with field cancerization, the patient in our case unfolded the second malignancy 34 years after the first malignancy and had no history of nicotine or alcohol consumption. The unprecedent duration and the absence of significant risk factors make it unlikely to be a typical next to the first primary. The history of permanent radium implants therefore powerfully suggests that the second cancer may be radiation-induced.

It is well recognized that radiation is carcinogenic. the one and the other environmental and therapeutic radiation has been linked with radiation-induced malignancies. There is an increase in childhood thyroid cancer after exposing to the atomic bomb detonations in Japan and Chernobyl reactor incident.18 Radium industry workers and radium dial painters were place to have an increased incidence of osteosarcoma, fibrosarcoma,9 and carcinoma of the paranasal sinuses and mastoid air cells919 A review involving 2500 patients with head and neck cancer attributed 070% of the cancers to previous therapeutic irradiation.5 Previous neck irradiation was associated with an estimated absolute risk of 44 exces thyroid cancers for 10.000 person years per Gy20 The risk was greatest for young children and almost all were papillary thyroid cancers of the solid/follicular type20 The use of radium-224 in the treatment of bone tuberculosis and ankylosing spondylitis in the 1940 and 1950 has contributed significantly to the increase of bone sarcomas,8,21 and malignancies of the breast, thyroid, liver, kidney, bladder and yielding tissue.22 Radium-226 used to treat skin haemangioma in the 1930 to 1960 was place to have significantly increased the risk of following gliomas, meningiomas23 and thyroid and other endocrine gland cancers.24 Radiotherapy to the scalp for tinea capitis was lay the foundation of to have increased the risk of skin cancer.6 Radiotherapy to the head, neck and chest was base to increase the risk of breast cancer25 and possibly increase the risk of parotid gland tumour26. Nasopharyngeal radium irradiation for otitis serosa in children and barotrauma in airmen and submariners in the 1940 to 1970 was place to have increased the risk of head and neck basal small room carcinoma27 and other head and neck tumours.28