Effectiveness of cervical cancer screening over cervical cancer mortality among Japanese women.
BACKGROUND
Various studies have revealed that cervical cancer (CC) screening significantly reduces both CC incidence and mortality in developed countries. Although Japan introduced a nationwide government funded annual CC screening for the women aged 30+ in 1982, the effectiveness of CC screening on CC mortality has not yet been evaluated by any prospective cohort study. Therefore, the present study evaluated the association of CC mortality with self-reported CC screening and some other factors by a nationwide cohort study.


METHODS
Baseline survey of the Japan Collaborative Cohort Study for the enrollment of subjects was completed during 1988-90 and followed until 2003. This study only analyzed 63,541 women, aged 30-79 years, who were free from any cancer history at enrollment.


RESULTS
During the follow-up period, 38 CC deaths were identified. The mean age at mortality was 67.0 years, with a mortality rate of 4.2 per 100,000 person-years. Participation rate in CC screening was 46.9%. Age-adjusted Cox model indicated significantly lower CC mortality [hazard ratio (HR) = 0.30, 95% confidence interval (CI) = 0.12-0.74] due to CC screening. Protectiveness remained almost the same (HR = 0.30, 95% CI = 0.12-0.76) when adjusted for age, body mass index and number of deliveries. The results also revealed that CC screening could reduce at least 50% of CC deaths even after excluding the effect of possible self-selection bias.


CONCLUSIONS
CC screening in Japan may reduce CC mortality significantly for women aged 30-79 years. However, further studies with more CC deaths and increased statistical power are needed to validate the findings.
Aklimunnessa
Khandoker
K
Department of Public Health, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan.
Mori
Mitsuru
M
Khan
M M H
MM
Sakauchi
Fumio
F
Kubo
Tatsuhiko
T
Fujino
Yoshihisa
Y
Suzuki
Sadao
S
Tokudome
Shinkan
S
Tamakoshi
Akiko
A
Motohashi
Yutaka
Y
Tsuji
Ichiro
I
Nakamura
Yosikazu
Y
Iso
Hiroyasu
H
Mikami
Haruo
H
Inaba
Yutaka
Y
Hoshiyama
Yoshiharu
Y
Suzuki
Hiroshi
H
Shimizu
Hiroyuki
H
Toyoshima
Hideaki
H
Wakai
Kenji
K
Ito
Yoshinori
Y
Hashimoto
Shuji
S
Kikuchi
Shogo
S
Koizumi
Akio
A
Kawamura
Takashi
T
Watanabe
Yoshiyuki
Y
Miki
Tsuneharu
T
Date
Chigusa
C
Sakata
Kiyomi
K
Nose
Takayuki
T
Hayakawa
Norihiko
N
Yoshimura
Takesumi
T
Shibata
Akira
A
Okamoto
Naoyuki
N
Shino
Hideo
H
Ohno
Yoshiyuki
Y
Kitagawa
Tomoyuki
T
Kuroki
Toshio
T
Tajima
Kazuo
K
D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008403:Mass Screening / Q000592:standards*; D008875:Middle Aged; D016016:Proportional Hazards Models; D002583:Uterine Cervical Neoplasms / Q000453:epidemiology / Q000401:mortality*; D014626:Vaginal Smears / Q000706:statistics & numerical data