Screening by routine mammogram is intended to catch breast cancer in women while it is still small and presumably easier to treat. So far, annual or biennial mammography has been advised to women starting from the age of 40. Some recently collected data have shown, however, that regular mammogram provides very modest benefit in terms of reducing death for breast cancer in women aged 40 to 49. In fact, without screening, 3.5 out of every 1,000 women in this age group will die of breast cancer in the next 10 years but regular mammography reduces that number to 3, i.e. the benefit derived from screening is only 0.5 per 1000 women!. Indeed, it has also been calculated that to save one life in this age group, 1,900 women must be screened annually for 10 years. The other 1,899 women will receive no benefit from mammography over that period, though they will field 1,330 call-backs for reassessment and 665 breast biopsies, and eight of them will be diagnosed with cancers whose prognosis will not be altered by detection via mammogram — either because they would never become dangerous or because they are so aggressive that there's little to be done. Data reported in recently published studies wherein women were randomly assigned to either a screening and a non screening group seem to confirm this contention. The U.S. Preventative Services Task Force thus decided in November 2009 that whether the benefits are worth the risks is a value judgment each woman should make for herself. Regular mammogram is instead highly reccomended after the age of 50 due to a significantly increased risk of breast cancer. In developing countries the incidence of breast cancer is significantly lower than in high income developed world but mortality due to the tumor is much higher. Even if the chance of detecting breast cancer in women younger than 50 is rather remote, the higher risk of dying of the disease may suggest that regular mammogram in women of developing countries in their 40s should still be encouraged .
Smoking is associated with an increase in breast cancer risk among postmenopausal women but there seems to be a definite increase also in non smoker women who have been extensively exposed to second hand smoke. These data were recently reported in the British Medical Journal. The study was based on the observation of nearly 80,000 women aged between 50 and 79 years enrolled in the Women’s Health Initiative Observational Study from 1993 to 1998. Invasive breast cancer appeared in 3,250 women during 10 years of follow-up. Smokers had a 16% increased risk of developing breast cancer after the menopause as compared to non smokers. For ex-smokers the risk was 9% and continued for up to 20 years after an individual had stopped smoking. The highest breast cancer risk was found among women who had smoked for over 50 years or more. What about non smokers? women who had never smoked but had lived or worked with smokers for prolonged times also appeared to be at increased risk for breast cancer. In particular, over 10 years’ exposure in childhood, over 20 years’ exposure as an adult at home and over 10 years’ exposure as an adult at work, increased the risk by 32% compared with those who had never been exposed to passive smoking. In low income and developing countries large declines in mortality are projected to occur in the near future for all of the principal communicable disease, maternal, peri-natal and nutritional causes, with the exception of HIV/AIDS. Meanwhile, the aging of the global population will result in significant increases in the total number of deaths caused by most non-communicable diseases such as cancer. In particular, increases in the prevalence of tobacco consumption and significant lifestyle changes in the population are bound to produce an increased risk of breast cancer in African women. Thus, efficient screening procedures for early detection of the disease need urgently to be implemented.
Cervical cancer is the second most common cancer in women worldwide and it is linked to persistent infection by human papilloma virus (HPV). Vaccination against HPV represents an important tool to obtain a primary prevention of the tumor. There are many strains of the virus but only a small number of them causes cancer. An international team of researchers has recently identified eight strains of the HPV responsible for more than 90% of cervical cancer cases. The study, which was published in the prestigious medical journal The Lancet, examined 60 years of data from 10575 cases of invasive cervical cancer in 38 countries. HPV was found in about 85% of cancer samples. More than 90% of these cases were caused by HPV types 16, 18, 45, 33, 31, 51, 58 and 35, in descending order of frequency. Only 1% of cases worldwide were linked to the infection by HPV types 26, 30, 61, 67, 69, 82 and 91. The former group of eight strains will represent the target for the next generation of HPV vaccines. Currently two vaccines are available in the market, Cervarix and Gardasil, which cover the infection by HPV strains 16 and 18. Gardasil covers 11 additional non oncogenic HPV strains which are responsible for genital warts. Prophilactic efficacy of the two HPV vaccines is almost 100% and they can prevent cancer cases directly linked to infection by HPV strains 16 and 18. Efficacy of the vaccination is obviously dependent upon the recipient not having been already infected with that type of HPV. Cancer cases due to 16 and 18 HPV strains represent about 60%-70% of total cases. Future efforts will focus on the production of second generation vaccines covering in addition the other six HPV strains (45, 33, 31, 51, 58 and 35) in order to prevent more than 90% of cases.
