Patterns of relapse following surgery and postoperative intensity modulated radiotherapy for oral and oropharyngeal cancer

Background. To investigate the patterns of relapse following intensity modulated radiotherapy (IMRT) given after radical surgery for oral and oropharyngeal squamous cell cancer. Patients and methods. One hundred and two patients with oral or oropharyngeal cancer were treated with radical surgery followed by IMRT up to a mean total dose of 60 Gy between years 2001 and 2007. Thirty-nine of the patients (%) also received concomitant weekly cisplatin. Forty of the patients had oral and 62 had oropharyngeal cancer. Data on the tumour, patient and treatment factors were collected. Following therapy the patients were followed by clinical examination, endoscopy and MRI/CT at 2- to 3-months interval up to 2 years and thereafter at 6-month intervals. Results. The mean follow-up time of the patients was 55 months (range, 26-106 months). The rate for local tumour control for the whole cohort was 92.2%: 87.5% for oral cancer patients and 96.7% for oropharyngeal cancer patients. The 5-year disease specific survival was 90.2% and 5-year overall survival 84.3%. During the follow-up eight locoregional recurrences were observed, three at the primary tumour site and one at regional nodal site and four at both sites. The mean time to primary tumour recurrence was seven months (range, 2-10 months) and to nodal recurrence seven months (range, 2-12 months). Distant metastasis occurred in six (6%) patients. The factors associated with poor prognosis were the primary tumour size and tumour site with oral cancers having worse outcome. The treatment was well tolerated with no unexpected toxicities. The most frequent late toxicity was dysphagia necessitating permanent PEG in five patients. This was correlated with the advanced primary tumour size and resulting in wide tumour excision and reconstruction. Conclusions. Surgery combined with postoperative radiotherapy given as IMRT results in low level of tumour recurrence.