The incidence and mortality trends of female breast cancer in Beijing, China: between 2004 and 2008

Abstract

To analyze the incidence and mortality trends of female breast cancer in urban and rural areas of Beijing from 2004 to 2008. The incidence and mortality data of female breast cancer from 2004 to 2008 were sorted from Beijing Cancer Registry Database, including 15 527 new diagnosed cases and 3219 deceased cases in total, covering population 29 351 258 person years; among which 11 065 new cases and 2378 deceased cases were from urban areas, covering 17 877 128 person years and 4462 new diagnosed cases and 841 deceased cases were from rural areas, covering 11 474 130 person years. The incidence cases aged 25 and above were divided into 13 age groups by 5 years. The cases under 49 years (≤ 49) and over 49 years (> 49) were separately defined as premenopausal group and postmenopausal group. Incidence and mortality rates in each year, age-specific incidence and mortality rates in urban and rural areas in Beijing were calculated. The annual standard incidence and mortality rates were adjusted by world population constitution; and the incidence rates ratio in different years related to the place of residence, urban or rural were calculated. JoinPoint software was applied to analyze the incidence trend and calculated the annual percentage of changing (APC). The age of female breast cancer patients in urban Beijing in 2004 was (55.83 ± 13.01), while it changed to (56.10 ± 12.80) in 2008, increasing by 0.27 years old. The proportion of the patients who were under 49 years declined from 38.32% (732/1910) in 2004 to 34.02% (894/2628) in 2008. While the average age of the patients in rural areas have improved 0.21 year old, from (52.15 ± 11.33) years old in 2004 to (52.36 ± 11.59) years old in 2008; and the proportion of the patients under 49 years also declined from 45.44% (314/691) in 2004 to 43.40% (454/1046) in 2008. From 2004 to 2008, the incidence and mortality rate of female breast cancer in urban areas of Beijing separately rose from 55.43/100 000 (1910/3 445 812) and 10.65/100 000 (367/3 445 812) to 70.70/100 000 (2628/3 717 436) and 15.01/100 000 (558/3 717 436). And in rural areas, those rates separately rose from 30.60/100 000 (691/2 257 953) and 5.54/100 000 (125/2 257 953) in 2004 to 44.78/100 000 (1046/2 336 040) and 7.49/100 000 (175/2 336 040) in 2008. After adjusting by world population constitution, the difference showed no statistical significance in mortality trend of female breast cancer in rural areas of Beijing (P > 0.05). In year 2004, the female breast cancer incidence rate ratio of urban to rural areas in Beijing fluctuated between 1.34 and 4.47, with the average ratio value at 1.81. In year 2008, the ratio value fluctuated between 1.15 and 2.37, with the average ratio value at 1.57. During 2004 and 2008, the peak age group of the female breast cancer incidence in urban areas was in 60 - 64 years old group, with the rate of 126.92/100 000 (998/786 300) whereas the mortality rate was increasing within aging. In rural areas the peak age groups of the incidence and mortality were separately in 50 - 54 and 80 - 84 years old groups, with the rate of 80.63/100 000 (793/983 516) and 29.17/100 000 (40/137 132) respectively. The incidence and mortality of breast cancer in urban areas in Beijing, as well as the incidence of breast cancer in rural areas in Beijing showed increasing trend annually. The gap in breast cancer incidence between rural and urban areas in Beijing was narrowing, while the incidence rate among different aging groups and the peak mortality rate showed significant difference between urban and rural areas in Beijing.