title: A feasibility study using three-dimensional conformal boost technique in locally advanced carcinoma of the nasopharynx.
abstract: To investigate the feasibility and efficacy of dose escalation using three-dimensional (3-D) conformal boost technique, 21 patients with stage III or IV nasopharyngeal cancer were enrolled in a prospective protocol. All patients with node metastases initially received external radiotherapy by conventional technique up to 70.2 Gy, followed by 3-D conformal radiotherapy (3-D CRT) to the boost part up to 79.2 Gy with 9 Gy increments (daily fraction of 1.8 Gy for 5 days). A modified technique with the same dose escalation of 9 Gy using 3-D CRT was applied to 7 patients without node metastases, who were treated by conventional technique up to 54 Gy, followed by 3-D CRT to boost up to a basic dose of 70.2 Gy, and then finally with dose escalation of 9 Gy. The protocol was relatively well tolerated by the majority of patients. Acute complications during the dose escalation schedule was low, with rare occurrences of grade 3 or 4 toxicity. Although late radiation-induced complications also appeared limited, 1 patient developed a temporal lobe necrosis and 2 patients suffered from sensory-neural hearing loss. There were no radiation-induced fatal complications. At a median follow-up of 48 months, only 3 patients experienced local failure and 2 patients developed distant metastases. The 5-year overall actuarial survival rate and recurrence-free survival rate for all patients were 68% and 85%, respectively. On the basis of acceptable morbidity and encouraging treatment results, we conclude that the dose escalation in 9 Gy increments using a 3-D conformal boost technique is relatively safe and efficacious, enough to be used routinely for locally advanced nasopharyngeal cancers.
authors.affiliation: Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University, College of Medicine, Seoul, Korea. gekim@yumc.yonsei.ac.kr
authors.forename: G E
authors.initials: GE
authors.lastname: Kim
authors.forename: J
authors.initials: J
authors.lastname: Lim
authors.forename: H C
authors.initials: HC
authors.lastname: Park
authors.forename: K C
authors.initials: KC
authors.lastname: Keum
authors.forename: Y B
authors.initials: YB
authors.lastname: Kim
authors.forename: S R
authors.initials: SR
authors.lastname: Moon
authors.forename: C G
authors.initials: CG
authors.lastname: Lee
authors.forename: J
authors.initials: J
authors.lastname: Seong
authors.forename: C O
authors.initials: CO
authors.lastname: Suh
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D002426:Cavernous Sinus / Q000473:pathology; D003389:Cranial Nerve Diseases / Q000209:etiology; D018572:Disease-Free Survival; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006402:Hematologic Diseases / Q000209:etiology; D006801:Humans; D015993:Life Tables; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011446:Prospective Studies; D011832:Radiation Injuries / Q000209:etiology; D011855:Radiodermatitis / Q000209:etiology; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods*; D019291:Skull Base / Q000473:pathology; D013280:Stomatitis / Q000209:etiology; D016019:Survival Analysis; D016896:Treatment Outcome; D014987:Xerostomia / Q000209:etiology