Materials and methods

The Case Recording System was approved to identify patients diagnosed with SNPC in the authors’ institution from January 1963 to December 2006. All were considered valuable if they contained data about patient demographics, pathological diagnosis, tumour details, therapeutic outcomes, and follow-up in the authors’ centre. Disease in all patients was restaged according to the American Joint Committee on Cancer (AJCC) classification system (2002 edition). During the years 1963 through 2006, 54 patients were diagnosed with primary SNPC. Each of the 54 patients had a confirmed pathological diagnosis of SNPC, including adenoid cystic carcinoma (ACC) in 36 patients (66.7%), mucoepidermoid carcinoma (MEC) in 11 patients (20.4%), and adenocarcinoma not otherwise specified (AC) in 7 patients (12.9%).

Tables 1 and 2 show the common presenting symptoms and the clinicopathological characteristics of the 54 patients (26 males, 28 females). Their median age was 44.5 years (range 23–74 years). According to the AJCC 2002 criteria, 18 patients had stage I and stage II disease (early stage), 36 patients had stage III and stage IV disease (advanced stage). Ten patients had neck nodal metastases at admission. In this study, 18 patients were histologically grouped into 10 with low-grade tumours and 8 with high-grade tumours in MEC and AC; in the other 36 patients, tumour differentiation was not specified.

In this study, 2 patient received surgery alone, 30 patient received radiotherapy alone and 22 patients had combined surgery and radiotherapy. Of them, eight patients received chemotherapy, including postoperative adjuvant chemotherapy of 1 cycle cisplatin monotherapy in one, palliative chemotherapy of 3 cycles of paclitaxel or cisplatin based chemotherapy in six patients and concurrent chemotherapy with weekly paclitaxel 60 mg in one patient.

Of the 30 patients receiving radiotherapy, 27 were irradiated using conventional techniques by lateral-opposed facial-cervical fields or preauricular fields at a daily dose of 2 Gy, and 3 recent cases were treated using intensity modulated radiation therapy at a daily dose range of 2.12–2.24 Gy to the gross tumour volume. Twenty-six patients who were treated with radiotherapy alone received a median dose of 80 (70–100) Gy. Four patients who were treated with radiotherapy alone received a total dose of 50–60 Gy because they refused further radiotherapy or developed distant metastasis. Of the 22 patients who received combined modality treatment, 7 had radiation followed by surgery (RT + S), while the other 15 received surgery prior to radiation (S + RT). In the former group, a preoperative radiation dose of 50–60 Gy was given to five of them and a high dose was delivered for two patients who were initially misdiagnosed as having nasopharyngeal squamous cell carcinoma. One was given 70 Gy, and the other was given 76 Gy by conventional external beam radiation followed by an additional boost of 15 Gy by brachytherapy and 15 Gy by stereotactic radiotherapy, but had no response. All the patients in the latter group received a total dose of 60–80 Gy according to the margin status. Forty-four patients were given radiation to the neck of 40–80 Gy regardless of the status of nodal metastasis and 1 patient was given radiation to the neck of 30 Gy because of distant metastasis.

Of the 24 patients undergoing surgery, 17 patients received primary surgery, while 7 patients received surgery for residual tumour in the nasopharynx after radiotherapy. The surgical margin was negative in 11 patients, and positive in 13 patients. Nasopharyngectomy was performed mainly via the transoropalatal or transmaxillary swing approach apart from three patients who underwent nasal endoscopic surgery. Neck dissection was performed for two patients with clinical radiographically suspected enlarged lymph nodes.

Follow-up was carried out by the oncologic outpatient clinic and by contact with the patients or their relatives using letter and/or phone call. The date of last follow-up was May 2011.

Results

The median living follow-up time for all the patients was 61.3 (1.8–245.2) months. Thirty-six (66.7%) patients were dead at the end of follow-up, 32 (59.3%) of them died of tumour disease. Twenty-two patients had loco-regional failure only; 9 patients had distant metastases only; 4 had both distant and loco-regional failure.