too little benefit from regular mammogram in women in their 40s

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 .

breast cancer risk factors and triggers

The genetic risk factors for breast cancer to develop are age, being a female, and having a family history of the tumor. In developed countries the risk of breast cancer in women at the age of 29, 39, and 49, is, respectively, one in 2000, one in 215, and one in 50. The lifetime risk of breast cancer reaches the highest values in women 70 and older: one in eight !. In the latter age group the incidence has progressively increased in the last fifteen years as it was one in ten in 1997 and one in nine in 2003. Why is it happening?  Cancer is a genetic disease but it needs some triggers to develop. There is now a good evidence that triggers of breast cancer can be found in lifestyle and environment and most probably are the followings: having fewer children and in later life; reduced breastfeeding; widespread hormone replacement therapy  (administered to contrast the debilitating symptoms of the menopause); increased alcohol consumption, and excess of weight (especially after menopause).  Oestrogen and other hormones are strongly implicated in breast cancer, and both pregnancy and breastfeeding reduce the amount of circulating hormone. Each birth decreases the risk of breast cancer by 7%. Every year of breastfeeding cuts the risk by 4.3%.

Women in developing countries have lower rates of breast cancer mainly because they start to have babies at a much younger age  and have higher parity. In Sub-Saharan Africa, higher incidence rates and relative frequencies of breast cancer have been reported in association with urban than with rural residence but, in any case, the incidence of the disease is much higher among white women in Africa than among black African women. Notice that this is just the opposite of what has been reported for afroamerican women as compared to white women in the USA (see my previous post on the topic).   In the future decade a progressive change in women’s lifestyle (on the model of western women) will probably take place also in many countries of the African continent and this will parallel a rise in breast cancer incidence. We should get prepared: the fight against breast cancer can be successful only if local health systems provide early diagnosis and proper treatment facilities.

breast cancer incidence in 2008 worldwide

Estimated age-standardised rates (World) per 100,000

Using the same source as in the previous post I am reporting the incidence of breast cancer worldwide in 2008.

“Breast cancer is by far the most frequent cancer among women with an estimated 1.38 million new cancer cases diagnosed in 2008 (23% of all cancers), and ranks second overall (10.9% of all cancers). It is now the most common cancer both in developed and developing regions with around 690 000 new cases estimated in each region (population ratio 1:4). Incidence rates vary from 19.3 per 100,000 women in Eastern Africa to 89.7 per 100,000 women in Western Europe, and are high (greater than 80 per 100,000) in developed regions of the world (except Japan) and low (less than 40 per 100,000) in most of the developing regions. The range of mortality rates is much less (approximately 6-19 per 100,000) because of the more favorable survival of breast cancer in (high-incidence) developed regions. As a result, breast cancer ranks as the fifth cause of death from cancer overall (458 000 deaths), but it is still the most frequent cause of cancer death in women in both developing (269 000 deaths, 12.7% of total) and developed regions, where the estimated 189 000 deaths is almost equal to the estimated number of deaths from lung cancer (188 000 deaths). “

It is also interesting to note that although the incidence of breast cancer in developing countries  is significantly lower than in developed countries, mortality due to this tumor is much higher in the former as compared to the latter. As already pointed out in previous posts,  this is due to the lack of efficient screening and early diagnosis of breast cancer in developing countries.

african american women and breast cancer

According to the Center of Environmental Oncology of the University of Pittsburgh Cancer Institute more African American women die of breast cancer than do white women.  This is probably due in part to racial disparities, higher exposure to environmental carcinogens, different lyfe style, and genetic factors. The US Centers for Disease Control and Prevention report that African American women with breast cancer fare worse than white women because they may have not access to quality health care or health insurance, or are often diagnosed with tumors that are more aggressive, or are exposed to toxic chemicals in a greater proportion at workplace. Although 1 in 8 Americans is African American, 1 in 3 houskeepers and blue collar workers, and 1 in 2 workers in sanitation jobs, are African American. The environmental risks of breast cancer include: cigarette smoking (including second-hand smoke); drinking more than two drinks of alcohol every day; obesity and being overweight especially after menopause; diets high in well done, smoked, preserved, fried or barbecued meats or fish, and diets low in fruits and vegetables. 

Relevant exposure to chemicals is found in polluted water and air, exhaust fumes from cars, trucks and buses, combustion products formed from burning wood chips, rubber, and when cooking meat or fish at high temperatures.  Workplace exposure to carcinogen chemicals occurs for dry cleaners, nurses, hairdressers, barbers, trucks/bus drivers. Personal risk factors associated with breast cancer include: family history of breast cancer; age older than 60; and use of hormone replacement therapy for more than a few months. 

What happens instead to African women? The rates of breast cancer seem much lower in most of Africa. Among regions, the age-standardized incidence rate is lowest in Central Africa (16.5/100,000) and highest in North America (99.4/100,000). The 5-year survival, however, is about 73 percent in industrialized countries, and 57 percent overall in developing countries. In summary, in low-income developing countries the incidence of breast cancer is lower than in the USA but the mortality rate is much higher. Accurate screening programmes to diagnose the tumor as early as possible represent the best tool to reduce breast cancer mortality but in most African countries they are still far from being implemented.

cellular phones and the risk of cancer: new insights.

Young mother speaking at her mobile phone, Hell Ville, Madagascar

There is an increasing concern in the  media  in the USA about the fact that long-term exposure to microwaves from cellular phones may lead to an increased risk of brain tumors, as well breast cancer and sperm reduction. Most of us have no idea that cell phones are small microwave radios that should not be kept directly on the body. Many researchers have demonstrated that the current standard of exposure to microwave during mobile phone use (cellular or cordless phones) is  not safe for long-term exposure. Although some studies have found no association, others suggest that the more hours of cellular phone use over time, the higher the risk of developing brain tumors. Risk also increases along with the level of power from the wireless device, years since first use, total exposure, and younger age when starting wireless phone use.
Cell phone’s microwave radiation seeps directly into soft fatty tissue of the breast and there already are some cases reported of breast cancer developed in close proximity to the site in the bra where cell phones are tucked and used for hours a day with a hands-free headset. For many young women today, tucking cell phones in the bra has become a cool, hip way to have simple access to these essential devices. As a way to get their newborn infant son to sleep through the night, some moms use i-Phone for the often-difficult task of pacifying them. They download several applications, including “BabySoothe” and “Lullabies”, and set them running throughout the night in close proximity to their baby’s head. Children’s brain (which double in size during the first year of life) is especially vulnerable to the emission of these two-way microwave radios, with their pulsed digital signals. Brains are not the only part of our anatomy that we need to be concerned about. According to several different studies, sperm count is 50% lower in men who use cell phones four hours a day—which is the case for a growing number of teenagers and young men.  Cells in human sperm exposed to cell phone radiation have been shown to die three times faster and become much sicker than those left alone. One may say that Africa is still free of this risk because of its poor economy and different lifestyle of inhabitant people. This is not completely true. I am not wrong if I believe that in most African countries, even the poorest, there is a widespread coverage by wireless communications facilities. These people may have no access to safe drinking water, or efficient health system, but, meanwhile, have no problem to use a cellular phone. The young mother shown in the photograph above, speaking at her mobile phone depicts this phenomenon: she lives in a country where prevention or early diagnosis of breast cancer or cervical cancer is not available but cellular phones are widespread among local people. Is the cellular phone lacking technologies to reduce exposure to microwave emissions an additional danger the developed countries are exporting to the low-income developing world ?.

targeted therapies for advanced cancer or primary prevention of tumors: ethical and economical issues.

Targeted terapies have significantly changed the treatment of cancer over the past 10 years. These drugs are now a component of therapy for many common malignancies, including breast, colorectal, lung, and pancreatic cancers, as well as lymphoma, leukemia, and multiple myeloma. They are a sort of smart bombs designed to target the cancer cells and block or slow the growth of certain types of cancer minimising damage to healthy cells . Most of them, however, improve survival by only a few weeks or months but they don’t cure cancer.

Targeted therapies are incredibly expensive. For example multidrug colorectal cancer treatment regimens containing bevacizumab or cetuximab cost up to $30,790 for eight weeks. In the United States, sales of erlotinib, a drug which is able to prolong survival by few months in a selected fraction (no more than 20%) of lung cancer, totalled $457 million in 2008 (Annual report to shareholders, 2008. Genentech). This is the reason why their use is an opportunity and a threat to every system that simultaneously seeks to improve the health of its members or citizens and to work within ever-tightening budget constraints.

These considerations open additional ethical issues. It is better to invest on a minimal increase in time survival for a patient with highly advanced gastrointestinal or pulmonary cancer or, instead, on the primary prevention of some preventable tumors when this is feasible?. Carcinoma of the cervix uteri represents a good example of preventable tumor. There is, in fact, compelling evidence that vaccination against human papilloma virus (HPV) in young girls allows total prevention of the tumor. Gardasil, the HPV vaccine, is currently being offered for approximately $120 per single dose. Three doses are required over a 6-month period, making the total cost for the HPV vaccine about $360. With the same amount of money which is required to treat a patient with advanced colon cancer administering the above multidrug treatment regimen ($30,790) we could pay for a vaccination campaign against HPV for 87,500 girls (!). While the patient with colon cancer will eventually die, the above population of future women will be be totally protected from carcinoma of the cervix uteri. I am well aware that biotechnological research in pharmacogenomics should not be stopped because it will eventually provide, in the future, the magic drug to stop cancer. At the same time, however, money should be used also for people of the third world to cope the emerging epidemic of preventable tumors at least because this will impact beneficially the life of the whole planet.

Cancer of the cervix uteri, a preventable tumor

Cancer of the cervix uteri is the second most common cancer among women worldwide. About 86% of the cases occur in developing countries. Every 10 minutes, a woman in Africa dies from cervical cancer, despite the fact that almost every case is preventable through a programme of screening, treatment and vaccination against the Human Papilloma Virus (HPV). In Madagascar it is the most commonly detected malignancy in females with an incidence >45 cases / 100000 inhabitants per year. According to the African Oxford Foundation "Globally there are over 500,000 new cases of cervical cancer annually and in excess of 270,000 deaths, accounting for 9% of female cancer deaths. 85% of cases occur in developing countries and in Africa Mortality rates vary seventeen fold between the different regions of the world. Cervical cancer contributes over 2.7 million years of life lost among women between the ages of 25 and 64 worldwide, some 2.4 million of which occur in developing areas and only 0.3 million in developed countries. Africa has 9 times the incidence of cervical cancer compared to the USA and 24 times the mortality. Cervical cancer incidence and mortality rates have declined substantially in Western countries following the introduction of screening programmes. Screening programmes in Africa, are however, often rudimentary or non-existent. The vast majority of women who suffer cervical cancer in Sub-Saharan Africa present with disease advanced far beyond the capacity of surgery or other treatment modalities to offer cure. Palliative care services are very poorly developed and therefore these unfortunate women are sentenced to a miserable end of life.