Pattern of local relapse of maxillary sinus carcinoma

Maxillary sinus carcinoma (MSC) is a rare disease with a variety of treatment options. The present study was undertaken to review the outcome of patients with treated MSC in order to clarify the factors related to local recurrence by analyzing CT findings. The study group comprised of 47 cases, 40 males and 7 females with a median age of 61 years (range, 40- 84 years) treated between 1988 to 1996 at the department of radiotherapy. CT was taken with a slice thickness of 5 mm and contrast material was routinely used. The mean follow-up period for the group was 45.0 months (range, 3-125 months). The treatment policy was either preoperative radiotherapy of 40Gy/16fr followed by maxillectomy or radical radiotherapy of 65Gy/26fr with partial maxillectomy during the course of radiotherapy. By using CT-simulation, wedge pair techniques were used in most patients with Cobalt or 6MV X-ray machines as treatment sources. Tumor extension was categorized into the following anatomical sites: orbital contents, other paranasal sinuses, posterior wall of the maxillary sinus, pterygoid plate/muscle, nasopharynx, infra-temporal fossa, base of the skull, anterior wall of the maxillary sinus, subcutaneous tissue, cheek mucosa, hard palate and alveolar bone. Local control was computed by using the Kaplan-Meier method and p value was measured by using Chi-squared test. The 5-year overall local control rates for all patients were 56%. The local recurrence was found in 19 of 47 patients (40.4%). Tumors extending to pterygoid plates (n=13) and pterygoid muscles (n=10) showed higher rate of local recurrences as compared to those without extensions (9/13 [69%] vs 10/34 [29%], p<0.02 and 7/10 [70%] vs 12/37 [32%], p<0.05, respectively). Extensions to nasopharynx (6/9, 66%) and base of skull (4/6, 66%) also showed higher rates of recurrence; however, those were not statistically significant. More than 80% of the relapse became manifest within 12 months of diagnosis and isolated local failure was the most common pattern. This analysis indicates that tumor extension to pterygoid plate/muscles, results in higher rates of recurrences. This may due to the difficult surgical accessibility of the tumor. During radiotherapy planning, special emphasis should be given to this sites of tumor extension to avoid possible local recurrence.