women's poverty, HIV infection, and cancer

Women bear a disproportionate burden of the world’s poverty. Statistics indicate that they are more likely than men to be poor and at risk of hunger. This is certainly due to  the systematic discrimination they face in education, health care, employment and control of assets.  According to some estimates, women represent 70 percent of the world’s poor.  

More than 30 million people are today living with HIV and, globally, women now account for half of all infections. Yet women increasingly make up the majority in sub-Saharan Africa where young women ages 15–24 are up to six times more likely to be HIV-positive than young men of the same age.

Why does it happen? According to the UN women website,  “gender inequality and violations of women’s rights make women and girls particularly susceptible, leaving them with less control than men over their bodies and their lives. Women and girls often have less information about HIV and fewer resources to take preventive measures. They face barriers to the negotiation of safer sex, including economic dependency and unequal power relations”.

What about women’s poverty and cancer incidence and mortality? I have already reported the higher incidence and the higher mortality of carcinoma of the cervix uteri in the developing world as compared to the high-income western world which is mainly due to the lack of primary or secondary prevention. Every day in Africa many women die of this totally preventable cancer which is related to human papilloma virus (HPV) infection.  Most of them even ignored the disease they were suffering from. Other than the lack of medical care and health facilities in the countries they live in, gender inequality and violations of women’s rights do play a major role in this tragedy too.

Patterns of cancer in developed and developing countries

 

In other posts I have been talking about the differences in rankings between developed and developing (low- and middle-income) countries in both incidence and mortality for cancer. The patterns vary by geography and economic status, which correlate roughly with the causes of cancer in the "environment" in its broadest sense.
The majority of cancers in more developed countries are those associated with more affluent lyfestyles - cancers of the lung, colon and rectum, breast, and prostate. In contrast, cancers of the liver, stomach, esophagus, and cervix - all related directly or indirectly to infectious agents - are relatively more common in developing countries.  The mix of common cancer in females varies as seen in the following table (source: Cancer Control Opportunities in low- and middle-income countries; see website in the list). Click to enlarge:

In developed countries the incidence of tumors of the breast, colon, lung and corpus uteri is higher than in low- and middle-income countries with a ratio, respectively, of 1.23/1; 1.95/1; 1.02/1; and 2.19/1. The mortality of these malignancies, however, is lower than in developing countries: breast 29.8% vs. 42.8%; colon and rectum 49.3% vs. 60.0%; lung 82.5% vs. 86.5%; and corpus uteri 21.32% vs. 33.8%. The higher mortality of these tumors in the developing world is mainly due to a significant delay in the diagnosis of the disease, i.e. the tumor is disclosed in a more advanced stage of progression, when therapy is less effective or useless. Because of these factors, the number of people dying of breast cancer and lung cancer in developing countries is likely to be equal to or even higher than the number of subjects dying of these tumors in the developed world.
In developing countries the incidence of tumors of the cervix uteri, stomach, liver, and esophagus, is much higher than in developed countries with ratios, respectively, of 6.49/1; 1.86/1; 4.08/1, and 8.12/1. The higher incidence of these tumors is broadly explicable by differences in exposure to certain infectious agents (HPV, HBV, HIV, etc) or carcinogens, but it is also strongly related to the lack of primary prevention (vaccination against HPV and HBV), to an ineffective secondary prevention (i.e., screening of carcinoma of cervix uteri), and to the lack of health facilities for early diagnosis and treatment. In fact, it is very frustrating to realize that in developing countries a significant proportion of people dying for cancer were suffering from preventable and/or curable malignancies. It is for this reason that all efforts should be made by the global cancer community to take immediate steps to slow and ultimately reverse the phenomenon.

Ho avuto già occasione di parlare delle differenze in termini di incidenza e mortalità dei tumori nei paesi sviluppati in confronto con quelli in via di sviluppo. Tali differenze si articolano in base alla geografia e alle condizioni economiche e quindi, in generale, alle condizioni ambientali nel senso più largo del termine. In genere, nei paesi sviluppati l'incidenza più elevata di alcune forme tumorali  (carcinoma del polmone, colon e retto, mammella e prostata) è correlata agli stili di vita più seguiti. Nei paesi in via di sviluppo, invece, si osserva una maggiore incidenza dei tumori associati, direttamente o indirettamente, all'esposizione ad agenti infettivi (carcinoma del fegato, della cervice uterina, dello stomaco e dell'esofago). Tutte queste forme tumorali sono molto aggressive ad eccezione, almeno in parte, del carcinoma della cervice uterina. La variabilità di incidenza e mortalità nel sesso femminile sono ben illustrate nella tabella.
Nei paesi sviluppati l'incidenza del carcinoma della mammella, colon, polmone, corpo uterino, è più elevata che nei paesi in via di sviluppo in ragione, rispettivamente, di 1.23/1; 1.95/1; 1.02/1; e 2.19/1.  La mortalità di questi tumori, però, è meno elevata che nei paesi in via di sviluppo: mammella 29.8% vs. 42.8%; colon e retto 49.3% vs. 60.0%; polmone 82.5% vs. 86.5%; corpo uterino 21.32% vs. 33.8%. Tutto ciò è dovuto al ritardo con il quale viene identificata la malattia che preclude l'efficacia delle terapie perchè il tumore si trova in una fase più avanzata. Come diretta conseguenza, la mortalità almeno per cancro della mammella e del polmone è più elevata nei paesi in via di sviluppo anche se l'incidenza è inferiore rispetto ai paesi sviluppati.
Nei paesi in via di sviluppo l'incidenza del carcinoma della cervice uterina, dello stomaco, del fegato, e dell'esofago è molto superiore a quella che si riscontra nei paesi sviluppati, in ragione, rispettivamente, di 6.49/1; 1.86/1; 4.08/1, e 8.12/1. L'incidenza più elevata è riconducibile alla diversa esposizione ad agenti infettivi (HPV, HBV, HIV, ecc) o carcinogeni, ma anche alla totale mancanza di misure di prevenzione primaria (vaccinazioni anti HBV o HPV), o all'insufficienza di misure di prevenzione secondaria (p.es. lo screening per il carcinoma della cervice uterina) e, infine, alla mancanza di strutture sanitarie che consentano una diagnosi precoce con relativo trattamento. E' sconfortante pensare che nei paesi in via di sviluppo la maggioranza dei decessi per cancro sia correlata a tumori prevenibili o curabili se diagnosticati in tempo. Tutto ciò deve rappresentare per la comunità globale che si occupa di cancro un motivo per attivarsi in modo fattivo affinchè tale tendenza venga ridotta o addirittura invertita.

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.