Tuesday, 4 December 2012

Cervical cancer more common in China than previously thought

New review shows high rates of high risk HPV infection and pre-cancerous CIN lesions in Chinese women
by Michael Woodhead
New findings show a high prevalence of high risk-HPV infection and precancerous lesions (CIN2+ ) in Chinese women, suggesting that the cervical cancer burden in China is much greater than previously thought, and that comprehensive screening and HPV immunisation efforts are warranted.
Researchers from the Cancer Institute/Hospital at the Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, say that estimates of cervical cancer rates in China have been based on a small and potentially unrepresentative pool of women in relatively affluent and developed urban areas such as Beijing.
Therefore they reviewed HPV and CIN rates in studies involving 30,207 women throughout China who had HPV testing and liquid-based cytology.
They found that the overall high-risk HPV prevalence was 17.7%. The study also showed high prevalence of every grade of CIN among Chinese women. Nearly 2% of women in the study harbored CIN3+, "an elevated prevalence that is most probably explained by the inadequacy of past and current cervical cancer screening practices in China, particularly among rural women," the researchers say.
Rates of high-risk HPV prevalence were similar in rural and urban areas but showed declines in women aged 25–29  in rural areas and at age 35–39  in urban women. These transient declines may be because the period of childbearing in China and elsewhere tends be accompanied by stronger family ties and fewer extramarital sexual affairs. The earlier dip in high-risk HPV prevalence in rural women may  be explained by the fact that age at first intercourse and first birth were 3 and 4 years earlier, respectively, for rural women compared to urban women. Furthermore, more rural women reported having two or more lifetime sexual partners (22%) than urban women (16%).
In rural and urban women, the CIN2 prevalence was 1.5% and 0.7% respectively and CIN3+ prevalence was 1.2%  and 0.6%, respectively. The prevalence of CIN3+ steadily increased with age, peaking in 45- to 49-year-old women. The steady rise of CIN3+ up to the age group of 45–49 is attributable to lack of lesion removal through screening.
The combined prevalence of CIN2 and CIN3+ in Chinese women (∼3%) was higher than the corresponding prevalence in other Asian countries, where it ranged between 0.5% in Thailand and 1.6% in Mongolia. In addition, the maximal prevalence of combined CIN2 and CIN3+ was observed in Chinese women older than 40–44 years, which was later than the maximal prevalence of CIN2+ in a recent meta-analysis of Asian women.
"Our findings document the inadequacy of current cervical cancer screening in China while indirectly raising the possibility that the cervical cancer burden in China is under-reported," they conclude.
"The high prevalence of CIN2+ in middle-age Chinese women should inform cervical cancer screening policies in China and other low- and intermediate-resource countries. Current cervical cancer screening recommendations are that women between the ages of 35 and 40 years be screened at least once  ... however, our findings show that Chinese women aged 40 years or older should also be screened as they harbour a substantial proportion of precancerous cervical lesions that accumulated over time and may still be the target of life-saving treatments," they suggest.
Read more: International Journal of Cancer

1 comment:

  1. In addition i want to say HPV infection can occur in both male and female genital areas that are covered or protected by a latex condom, as well as in areas that are not covered.what is a wart


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