Incidence of metachronous second primary cancers in Osaka, Japan: update of analyses using population-based cancer registry data:
(define: metachronous - Two or more cancers appearing at different points in time.)
Summary
Cancer survivors are at excess risk of developing second primary cancers, but the level of risk is uncertain in Japan.
To investigate the risk of survivors developing second primary cancers, we conducted a retrospective cohort study using data from the Osaka Cancer Registry. Study subjects were all reported cases aged 0-79, who were first diagnosed with cancer between 1985 and 2004 in Osaka and survived for at least 3 months, followed up through December 2005.
A metachronous second primary cancer was defined as any invasive second cancer which was diagnosed between 3 months and 10 years after the first cancer diagnosis.
The main outcome measures were incidence rates per 100,000 person-years, cumulative risk and standardized incidence ratios (SIRs) of second primary cancer. Metachronous second primary cancers developed in 13,385 (3.8%) out of 355,966 survivors after a median follow-up of 2.5 years. Sex-specific incidence rates of metachronous second primary cancer per 100,000 person-years increased with age, and were higher among males than females (except for age 0-49), but these rates did not differ over the study period. The 10-year cumulative risk was estimated as 13.0% for those who first developed cancer in their sixties (16.2% for men, 8.6% for women). The SIRs among those with first cancer at 0-39 years old and 40-49 years old were 2.13 and 1.52, respectively, in both sexes, while the SIRs among cancers of the mouth/pharynx, esophagus and larynx were much higher than one as for site relationships.
We showed that cancer survivors in Osaka, Japan, were at higher risk of second primary cancers compared to the general population. Our findings indicated that second primary cancers should be considered as a commonly encountered, major medical problem. Further study is required to advance our understanding for effective measures against multiple primary cancers.
To investigate the risk of survivors developing second primary cancers, we conducted a retrospective cohort study using data from the Osaka Cancer Registry. Study subjects were all reported cases aged 0-79, who were first diagnosed with cancer between 1985 and 2004 in Osaka and survived for at least 3 months, followed up through December 2005.
A metachronous second primary cancer was defined as any invasive second cancer which was diagnosed between 3 months and 10 years after the first cancer diagnosis.
The main outcome measures were incidence rates per 100,000 person-years, cumulative risk and standardized incidence ratios (SIRs) of second primary cancer. Metachronous second primary cancers developed in 13,385 (3.8%) out of 355,966 survivors after a median follow-up of 2.5 years. Sex-specific incidence rates of metachronous second primary cancer per 100,000 person-years increased with age, and were higher among males than females (except for age 0-49), but these rates did not differ over the study period. The 10-year cumulative risk was estimated as 13.0% for those who first developed cancer in their sixties (16.2% for men, 8.6% for women). The SIRs among those with first cancer at 0-39 years old and 40-49 years old were 2.13 and 1.52, respectively, in both sexes, while the SIRs among cancers of the mouth/pharynx, esophagus and larynx were much higher than one as for site relationships.
We showed that cancer survivors in Osaka, Japan, were at higher risk of second primary cancers compared to the general population. Our findings indicated that second primary cancers should be considered as a commonly encountered, major medical problem. Further study is required to advance our understanding for effective measures against multiple primary cancers.
© 2012 Japanese Cancer Association
