Influence of age on cervical cancer survival in Japan.

BACKGROUND

Relative 5-year survival for cervical cancer has been reported to be lower in older women in Japan. A population-based study was carried out to clarify why increased age is associated with decreased survival in spite of a nationwide cervical cancer screening program having been carried out since 1982 in Japan.

METHODS

The Osaka Cancer Registry's data were used to investigate associations between age groups and survival for cervical cancer patients. Survival analysis was restricted to the reported 8966 cases diagnosed in 1975-1996 who lived in Osaka Prefecture (except for Osaka City), or resided in Osaka City in 1993-1996, since active follow-up data on vital status 5 years after the diagnosis were available.

RESULTS

Relative 5-year survival for cervical cancer cases was lower in older age groups (88.6% in <30 years, 78.1% in 30-54 years, 67.7% in 55-64 years and 54.4% in 65+ years), as was the proportion of the detection by screening (6.3, 9.8, 9.2 and 6.0%), the proportion of the localized stage (83.0, 67.3, 51.0 and 42.7%) and the proportion of women who underwent surgery (79.2, 83.2, 65.6 and 35.2%). Among localized cases detected with screening, the survival in those > or =55 years old was >92% and almost comparable with that in 30 to 54 year olds, but significantly lower among those detected without screening.

CONCLUSION

Lower survival among older women was caused mainly by the presence of more advanced disease at diagnosis. Further extension of the nationwide cervical cancer screening program should result in improved diagnosis of earlier stage disease, which might improve differences of cervical cancer survival among these age groups.