The following is the edited transcript and figures from a webinar presentation made by Dr. Heather Wakelee, medical oncologist and Associate Professor at Stanford Cancer Center, on Never-Smokers and Gender Differences in Lung Cancer.

Let's move to biological differences of risk of lung cancer between men and women.

A new study from the National Institutes of Health is being published in the journal of Clinical Oncology and demonstrates that elevated levels of C-Reactive Protein (CRP), a biomarker of chronic inflammation, is associated with lung cancer.

It seems obvious: environmental tobacco smoke (ETS)/passive smoke exposure from being around smokers, can be harmful and may cause cancer in never-smokers. A new paper in the Journal of Clinical Oncology by Lee and colleagues from Korea actually offers some evidence that highlights this, showing that never-smokers in Korea were less likely to have an EGFR mutation if they were exposed to ETS.

As we head in to National Lung Cancer Awareness Month, we are all aware of the role cigarettes and tobacco play in the cause of lung cancer. We also are aware that not ALL lung cancers are caused by smoking, and that 10% of men and 20% of women who are diagnosed in the U.S. with lung cancer are never-smokers.

The role of hormones in the development and progression of lung cancer in women has generated much interest. Unfortunately, a lot of the data to date has been observational, which doesn't establish a "cause and effect" relationship. The Nurses Health Study (more on this below) is a good example: a large cohort of women was observed over time. The women completed questionaires on all sorts of exposures (diet, hormone replacement therapy, tobacco, etc), and they were followed over time.

When I joined GRACE earlier this month, a question was posed by a reader regarding whether there is an increasing frequency of the diagnosis of lung cancer in women who have never smoked. This is a very interesting question that those of us who specialize in lung cancer frequently wonder about.

Admit it. You have probably wondered why you or your loved one was unlucky enough to get lung cancer while that obnoxious neighbor or coworker has smoked 2 packs a day for 50 years and doesn’t even have a cough. In fact, only about 15% of male smokers and 10% of female smokers eventually develop lung cancer. The field at large has been searching for why some smokers get lung cancer and others don’t for many years, and while progress has been made the answer has been elusive.

Over the past few years, the role of post-operative, also known as adjuvant, chemo has become increasingly accepted as a standard of care. Several trials have shown an improvement in survival at about 5 years that is in the 5-15% range for recipients of chemo.

People who have been following my comments know that I am often questioning the wisdom of surgery in patients who don't fit the usual criteria for resection, which is most commonly pursued in stage I and II NSCLC and is often considered an option for some patients with stage IIIA NSCLC. To provide a very quick review of NSCLC staging, it's a combination of three factors:

1) Tumor (T) stage -- from 1 to 4, going from smallest and easiest to remove to hardest or largest to remove

2) Node (N) stage -- from 0 to 3, going from none to further distances from the main tumor

A cancer has to grow faster than the tissue around it to become a tumor. Progressive growth is therefore a central feature of a cancer and a critical factor in distinguishing cancerous nodules from benign ones. There is a characteristic "volume doubling time" (VDT), the interval it takes for a nodule to double in volume. It's worth keeping in mind that because a nodule is generally spherical, an increase in the diameter by just 28% (such as a 2 mm increase from 7 to 9 mm) actually represents a doubling of the volume of a nodule.