Lung Cancer and Women

A new report on lung cancer in women has been published by the Women’s Health Policy and Advocacy Program at Brigham & Women’s Hospital.  Called “Out of the Shadows“, the report seeks to raise awareness about lung cancer, currently the leading cause of cancer deaths in women, and more importantly, to increase funding for research into its prevention, detection and treatment. (HT to Booster Shots, the LA Times’ fabulous health blog, for highlighting the report.)

I encourage you to read the report, which is well written and comprehensive. For a more scientific summary of the issues, I would point you to December’s Seminars in Oncology, a special issue devoted to lung cancer in women.

The report is quite open about the stigma that smoking brings to the issue of lung cancer advocacy, and so seeks to focus our attention instead on those lung cancers that occur in non-smokers, which are on the rise as smokers decline as a percentage of the overall population. Although this rise in lung cancers among non-smokers is not universally accepted, nonetheless one in five lung cancers in women occur in those who have never smoked. That’s a significant number of cancers that deserve our attention and advocacy as much as breast and cervical cancer.

Factors that differentiate lung cancers in women from those in men include a lower mortality in women as well as high rates of cancers among female non smokers.  Differences in hormonal mileau in men and women as well as in the presence of growth regulator genes linked to X chromosome have been suggested as explanations for these sex differences, along with other factors, including the variable susceptibility between men and women to the effects of environmental carcinogens.

Despite the fact that smoking is linked to 80% of lung cancer deaths in women, the report devotes surprisingly little space to strategies aimed at reducing cigarette smoking in women and its policy implications include no strategies towards this goal. I suspect this is because they are trying to drive us away from thinking about lung cancer as just a nicotine related disease, but it is, so let’s face it.

I also find it frustratingly that we have so little information on potential environmental carcinogens other than cigarette smoke that may be causative in lung cancer. The coincident rise in asthma among women makes me believe that the environmental connections are there and must be found if we are to prevent further increases in pulmonary disease and cancer in women.

The report does a nice job summarizing new technologies for lung cancer screening and treatment without hype, although it is not necessarily without bias. For example, while presenting screening lung CT as controversial, and acknowledging the potential for leadtime bias in early screening interventions, the conclusion tends to focus on the more positive aspects of this screening. It also discusses new non-invasive screening tests by name that are not yet FDA approved, which is sure to get more than a few folks in to their doctor’s office asking for these tests.

Overall, however, I found the report to be both informative, well-referenced and appropriate reading for both lay and professional audiences, and applaud the Women’s Health Policy Advocacy Group for taking on this important health issue for women.

The Gynecologist and Lung Cancer 

As a gynecologist, these are the things I tend to thinks about when it comes to lung cancer in women –

1. HRT and lung cancer – Although hormone replacement has been linked to an increase in lung cancer mortality in women, HRT users do not have higher rates of lung cancer than non users. This correlates with what we know about lung tumors, which is that they can have receptors for estrogens, which in turn can act as growth promotors.  This would suggest caution in using HRT in smokers or others at increased risk for lung cancer as well as a potential role for hormonal treatment in lung cancers similar to hormonal treatments used in breast cancer. (Oral contraceptive use is not linked to lung cancer incidence or mortality.)

2. HPV and Lung Cancer – Is there a link? – I was surprised to see no mention in the report of the possibility of a link between HPV infection in the respiratory tract and lung cancer. It is an intriguing theory that has biologic plausibility. With the coincident shifts in values regarding oral-genital sexual activity and the HPV epidemic among young people, there is an urgent imperative to either repudiate or validate this theory, particularly since we now have an effective vaccine against two of the cancer causing strains of HPV.