Second Malignant Tumors After Treatment of Nasopharyngeal Carcinoma: Four Case Reports and Literature Review

Abstract

The purpose of this study was to identify the histopathology, location, and latency interval for the development of second malignant tumors (SMT) after successful treatment for nasopharyngeal carcinoma (NPC). Of 55 patients, four developed SMT after successful treatment of NPC in a single institutional series for an incidence of 7%. An additional 31 patients with SMT after treatment for NPC were identified from the literature. At minimum, all patients were treated with radiotherapy to the primary site. The histopathology of SMT included sarcoma (69%), squamous cell carcinoma (17%), adenocarcinoma (6%), meningioma (6%), and lymphoma (3%). SMT occurred at various sites in the head and neck, but most (51%) arose in the sinonasal cavity. For the entire group, the mean latency interval between treatment for NPC and the development of SMT was 11.8 years. These findings indicate that the development of SMT in patients achieving long-term survival after treatment for NPC may be radiation induced. Long-term follow-up for these patients is important to assess for this potentially late complication.

MRI of radiation-induced tumors of the head and neck in post-radiation nasopharyngeal carcinoma

“…5). The increased incidence of tongue carcinoma and its relationship to RT were first reported by Teo et al [5], since which time there have been several other reports showing the tongue to be at risk after treatment for NPC [9,10]. Two patients in this study had SCC in the pharynx, one involving the palatine tonsil and the other the pyriform fossa in the hypopharynx.…”

“…The nasopharynx and sphenoid sinus receive the full dose of radiation but surprisingly, with the exception of the brain, this was the least frequent region to develop an RIT. Finally the mandible has been cited as a common site for RIT, especially sarcomas [8,9], but no cases were recorded in this study.…”

“…A study by Liu et al [8] showed that of 15 sarcomas in the head and neck, 8 arose in the maxilla or nasal cavity and paranasal sinuses, while Lee et al [3] reported 2 cases and Dickens et al [14] 4 cases of osteosarcoma of the maxilla. Malone et al [9] reported a case of adenocarcinoma in the maxillary sinus and hard palate and a literature review revealed 11 further sinonasal RITs, which included a study by Ko et al [4] with 8 malignant fibrous histiocytomas arising in the nasal cavity or maxillary sinus.…”

“…Since then there have been several case series of mucoepidermoid carcinoma arising after radiation exposure including eight by Modan et al [25], nine by Stites et al [26] after irradiation for childhood cancer, and nine by Beal et al [27] of which two patients had received RT for NPC. Meningiomas are well known complications of cranial irradiation [28] but are rarely reported in NPC with only two other reported cases of meningiomas in the literature [9]. This is rather surprising given that the inferomedial temporal lobe is included in the radiation field and is itself a common site of radiation injury.…”

“…However, longer survival results in an increased opportunity for the complications of RT to develop. These complications include radiation-induced tumors (RITs), which although rare, have been reported in several case series with an incidence ranging from 0.04 to 7% [2][3][4][5][6][7][8][9][10][11]. The radiologist should be aware of the common sites of RITs so these can be scrutinized on follow-up scans, and be aware of their radiological appearances.…”