Influence of postsurgical residual tumor volume on local control in radiotherapy for maxillary sinus cancer

Background: The aim was to study the influence of postsurgical gross residu al tumor volume on local control of maxillary sinus cancer treated with rad iotherapy combined with debulking surgery. Methods: Forty-three patients who underwent combined surgery and radiothera py (50-72 Gy, median 60 Gy) for squamous cell carcinoma of the maxillary si nus were reviewed. Gross residual tumor volume (GRTV) after surgery was mea sured on computed tomograms obtained during the radiotherapy planning. Pati ents were classified according to GRTV as follows: group AA, GRTV = 0 (micr oscopic residual, n = 2); group A, GRTV <10 cm(3) (n = 24); group B, 10-40 cm(3) (n = 9); and group C <greater than or equal to> 40 cm(3) (n = 8). The relationship between local control and GRTV was analyzed using univariate and multivariate analysis. Results: The 2-year local control rate for all patients was 62%. The differ ences in local control rates between groups AA, A and B were not significan t (P > 0.05), but the rate was significantly lower in group C than in the o ther groups (69% at 2 years vs 31% at 1 year, P < 0.001). Multivariate anal ysis showed that GRTV (P = 0.002) and histological differentiation (poorly differentiated histology was favorable, P = 0.035) were independent prognos tic factors and that intraarterial chemotherapy and administered total dose were not. Local control in groups A and B significantly depended on the to tal dose of radiotherapy, with 2-year control rates of patients receiving 5 0 Gy (n = 6) and <greater than or equal to>60 Gy (n = 27) of 17% vs 79%, re spectively (P < 0.001). Conclusions: Our data suggest that adequate, not complete, debulking associ ated with a total radiotherapy dose of <greater than or equal to>60 Gy can provide satisfactory local control for patients with squamous cell carcinom a of the maxillary sinus.