Why is the incidence of lung cancer in females (pink dashed line below) heading in the wrong direction?
In women, lung cancer is the number one killer, now surpassing breast cancer
Whilst smoking undoubtedly should be stopped to help reduce the risk of lung cancer and other diseases, it is not the only factor to consider. The number of men being diagnosed with lung cancer is going down, but the rate among women is going up. Could it be that it is not necessarily cigarette smoke that is causing an increased rate of lung cancer in women?
In women, lung cancer is the number one killer, now surpassing breast cancer. The proportion of lung cancer cases in women related to smoking are approximately 50% of that seen in males. This suggests that there are other roles in development of lung cancer.
Also, lung cancer is the leading cause of all cancer-related deaths in women worldwide; worldwide it is responsible for nearly 1 million deaths a year. Because there is such a high incidence and high death rate in lung cancer, it is one of the most lethal human cancers we have to face.
Oestrogen Influence
The major and most obvious biological difference between men and women is in the ratio of the two female sex hormones, oestrogens and progesterone, and how they function within the male and female body. An increasing amount of evidence suggests that female hormones, in particular oestrogens, play a key role in lung cancer development.
Oestrogen receptors ERa (receptor Alpha) and ERb (receptor Beta) have been detected on lung cancer cells. It is the balance between, and function of, the two (ERa and ERb) that is the possible deciding factor as to whether we could develop lung cancer, breast cancer, or any oestrogen related cancers.
Hormonal balance
Menopausal women are much more susceptible to the detrimental effects of cigarette smoke, compared with men of the same age. This would be due to the sharp decline in oestrogens during menopause; oestrogens are not only a potent antioxidants, they are a group of protective hormones, when working in harmony.
When our sex hormones fluctuate, and an imbalance occurs, we are at a much higher risk of contracting lung cancer. Our hormones no longer protect us because they are not working in harmony. Instead, and unknowingly, they are working against us, because there is a breakdown in physiological function.
Research on hormonal connection
An interesting study, called, ‘The characteristics of menstruation and pregnancy and the risk of lung cancer in women’, showed that women who were still menstruating or who were pregnant showed no associated risk with lung cancer. On the other hand, there was an increased risk of lung cancer for women who had had a non-natural menopause (full hysterectomy- bilateral oophorectomy), compared to women who had had a natural menopause.
Furthermore, the study observed that the younger the women was, when she entered menopause (before age 45), the greater the risk of developing lung cancer compared to older women. This suggests that there is a hormonal connection.
When there are fluctuating hormones levels there will be an imbalance. When there is balance within the body and its systems we are much less likely to contract cancers in general, and we will certainly age at a lesser speed. Balance is everything!
References
- Lung cancer in women: role of estrogens. Subhankar Chakraborty, Apar Kishor Ganti, Alissa Marr, Surinder K, Batra. Expert Rev Respir MEd. 2010 Aug 4(4):509-18.
- Characteristics of menstruation and pregnancy and the risk of lung cancer in women. A, Parent ME, Siemiatycki J. Characteristics of menstruation and pregnancy and the risk of lung cancer in women. Int. J. Cancer. 2009;125(10):2428–24.
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