The importance of long-term follow-up of head and neck cancer patients for reliable survival analysis.
OBJECTIVE
Analyze the influence of patients lost to follow-up in estimated survival rates calculated by the Kaplan-Meier method.


METHODS
Only patients with previously untreated squamous cell carcinoma of the upper aerodigestive tract were selected. For the patients lost to follow-up anytime, the last medical evaluation date was collected to calculate the "estimate A" survival time. If the same patient returned to our outpatient clinic or further health information was obtained, the updated last information/evaluation date was also collected to calculate "estimate B" survival time. The survival curves considering "estimate A" and "B" survival rates were compared.


RESULTS
The overall 5 and 10-years survival rates for all patients calculated for "estimate A" were 54.0% and 46.0%, respectively; compared with 42.8% and 28.2% when were calculated considering "estimate B" (P < 0.001).


CONCLUSIONS
Close follow-up of the head and neck cancer patients is essential for an accurate estimate of survival by Kaplan-Meier method.
Priante
Antonio Vitor Martins
AV
Head and Neck and Otorhinolaryngology Department, Centro de Tratamento e Pesquisa Hospital do Câncer A. C. Camargo, Sao Paulo, Brazil. priante@uol.com.br
Carvalho
André Lopes
AL
Ribeiro
Karina de Cássia Braga
Kde C
Contesini
Hirde
H
Kowalski
Luiz Paulo
LP
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000401:mortality* / Q000473:pathology; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000401:mortality* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010349:Patient Compliance; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D013997:Time Factors