title: A retrospective study of the role of intracavitary brachytherapy and prognostic factors determining local tumour control after primary radical radiotherapy in 903 non-disseminated nasopharyngeal carcinoma patients.
abstract: The aims of this retrospective study were to determine the role of intracavitary brachytherapy given shortly after external beam radiotherapy in the primary radical treatment of non-metastatic nasopharyngeal (NPC) cancer patients, and the prognostic factors governing local tumour control. From 1984 to 1989, 903 patients with non-disseminated NPC who had had no previous treatment were managed at the Prince of Wales Hospital, where investigation and treatment methods had been standardized according to a departmental protocol. The external radiotherapy dose of 60.0-62.5 Gy in 6 weeks was given to all patients. Parapharyngeal booster radiotherapy with a single photon beam to 20 Gy in 2 weeks was given to those with parapharyngeal tumour extension. Computed tomography of the nasopharynx and skull base, and pretreatment nasopharyngoscopy and biopsy were performed in all patients. Nasopharyngoscopy was repeated at 4 weeks after the last day of external irradiation. Local persistence in 99 patients was treated additionally by intracavitary brachytherapy to 24 Gy in three fractions over 15 days. Fifty-one patients with early stage primary disease (Ho Stage T1 and T2n (nasal)) who responded completely to external radiotherapy were given adjuvant intracavitary brachytherapy to 18 Gy in three fractions over 15 days. Intracavitary therapy was an inadequate salvage treatment for the locally persisting T3, T20 (oropharyngeal) and T2p (parapharyngeal) disease, but there was a trend towards improved local control after intracavitary brachytherapy for the locally persisting T1 tumours. Adjuvant brachytherapy did not enhance local tumour control for the early T-stage tumours that completely responded to external radiotherapy. Both forms of intracavitary brachytherapy were safe with few and acceptable complications. In the 903 non-disseminated NPCs, the patient's age and tumour involvement of the skull base and cranial nerves were significant independent prognostic factors governing local tumour control. In the 358 patients with Ho T3 disease, tumour involvement of the orbits and the laryngopharynx significantly worsened local tumour control. The presence of local persistence at 4 weeks after external radiotherapy, for which therapeutic brachytherapy was given, was marginally significant as a prognostic factor in addition to the presence of cranial nerve palsy.
authors.affiliation: Prince of Wales Hospital, Shatin, Hong Kong.
authors.forename: P M
authors.initials: PM
authors.lastname: Teo
authors.forename: W H
authors.initials: WH
authors.lastname: Kwan
authors.forename: P
authors.initials: P
authors.lastname: Yu
authors.forename: W Y
authors.initials: WY
authors.lastname: Lee
authors.forename: S F
authors.initials: SF
authors.lastname: Leung
authors.forename: P
authors.initials: P
authors.lastname: Choi
mesh_terms: D000206:Actuarial Analysis; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001918:Brachytherapy; D002277:Carcinoma / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D003389:Cranial Nerve Diseases / Q000473:pathology; D018572:Disease-Free Survival; D004724:Endoscopy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007822:Laryngeal Neoplasms / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control*; D009367:Neoplasm Staging; D009918:Orbital Neoplasms / Q000473:pathology; D010243:Paralysis / Q000209:etiology; D011379:Prognosis; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D016879:Salvage Therapy; D012886:Skull / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed