The effect of loco-regional control on distant metastatic dissemination in carcinoma of the nasopharynx: an analysis of 1301 patients.
OBJECTIVE
This study evaluated the effect of loco-regional control on incidence of distant metastases in patients with nasopharyngeal carcinoma.


METHODS
Retrospective analysis was performed on 1301 patients with nasopharyngeal carcinoma treated from 1976-1989 in our hospital. The effect of different prognostic indicators on distant metastases free survival (DMFS) was analyzed, including T stage, N stage, sex, and loco-regional control. The significance of loco-regional control in distant metastatic dissemination was further studied with period and subgroup analysis. Cox regression was performed to identify the independent prognostic variables.


RESULTS
Patients with loco-regional relapse had significantly higher distant metastases rate than patients with loco-regional control (time-adjusted distant metastases rate at 5 years was 40.7% vs. 29.4%, p = 0.0012). By period analysis, the effect of loco-regional control on distant metastases was found to be significant in the first 2 years from diagnosis. Subgroup analysis showed that loco-regional relapse was associated with significantly higher distant metastases rate in patients with T1, N0, and N1 disease (p = 0.001, 0.001, 0.0226, respectively). The Cox regression model also confirmed loco-regional control as an independent prognostic indicator of distant metastases (p = 0.0001) besides T stage (p = 0.0006) and N stage (p = 0.0001).


CONCLUSIONS
Loco-regional relapse is a significant risk factor for development of distant metastases. Further effort should be made to improve loco-regional control and to eradicate distant metastases.
Kwong
D
D
Department of Radiotherapy and Oncology, Queen Mary Hospital, Hong Kong.
Sham
J
J
Choy
D
D
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D009362:Neoplasm Metastasis / Q000517:prevention & control*; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models; D012008:Recurrence; D012044:Regression Analysis; D012189:Retrospective Studies; D012727:Sex Characteristics