THE ROLE OF BRACHYTHERAPY IN EARLY-STAGE NASOPHARYNGEAL CARCINOMA

Purpose: To present the treatment results and assess the optimal radia tion dose and the role of brachytherapy in early stage nasopharyngeal cancer (NPC). Methods and Materials: One hundred eighty-three patients with Stage I and LI (American Joint Committee on Cancer Staging Syste m, 1987) NPC completed the planned radiotherapy in our institution fro m 1979 to 1991. In 133 patients, radiotherapy was given to the nasopha rynx by external beam to 64.8-68.4 Gy. Further boost was done by high dose rate (HDR) brachytherapy for 5-16.5 Gy in one to three fractions. For the remaining 50 patients, a course of external radiotherapy to t he nasopharynx for 68.4-72 Gy was given to nasopharynx. Age (>40 or no t), sex, neck boost or not, brachytherapy, and irradiation dose were a nalyzed to determine significant factors that influence the probabilit ies of local control and actuarial survival. Results: The 5-year disea se-specific survival was 85.8% and local control was 83%, Only the bra chytherapy and irradiation dose significantly affected the results. Th e use of the brachytherapy had significant impact on overall survival and local control. Furthermore, we compared the prognostic effect of v arious radiation dosage among Group I of 50 patients (<72.5 Gy, no bra chytherapy, excluding four patients who received brachytherapy), Group II of 71 patients (72.5-75 Gy; one to two fractions of brachytherapy) , and Group III of 58 patients (>75 Gy; three fractions of brachythera py). Five-year disease-specific survival rates of Group I, Group II, a nd Group III were 77, 95.5, and 82.4%, respectively. Five-year local c ontrol rates were: 73.7, 93.9, and 79.5%. We found that the Group II h ad the best actuarial survival and local control rate (log-rank test, p < 0.05). Most patients receiving brachytherapy encountered foul odor because of nasopharynx crust; 12 of them had palate or sphenoid sinus floor perforation or nasopharynx necrosis. None of the patients witho ut brachytherapy experienced the same complications. Conclusions: The optimal radiotherapy dose to the nasopharynx area in early stage NPC m ay be within 72.5 to 75 Gy by our treatment protocol. A dose of more t han 75 Gy did not have significant local control or survival advantage . The use of brachytherapy to elevate radiation dose had significant l ocal control and survival benefit for early stage NPC patients, but th e fractionation size should be decreased to reduce the complications. Copyright (C) 1996 Elsevier Science Inc.