Basic Cancer Info

Although there has always been lattitude for individualizing treatment, I think developments in the last few years have added so many options that pretty much any standards we had from a few years ago have eroded.

Mrs. M was a 46 year-old woman who, despite having never smoked, was diagnosed with metastatic adenocarcinoma of the lung. She had a nice initial response to chemotherapy, and when she eventually progressed, she was treated with Iressa (an EGFR inhibitor similar to Tarceva which is no longer available in the US). To both her and her doctor’s delight, she had near resolution of her lung mass and most of her liver lesions after 2 months on Iressa. Unfortunately, after remaining stable for 10 months, her restaging CT scan showed one lesion in the liver was growing.

Although it's uncommon, hypertrophic osteoarthropahy, or HPOA, is an odd and therefore memorable syndrome that can be a side effect of lung cancer. It features an abnormal proliferation of skin and bone tissue, primarily in the hands and feet. Patients can develop clubbing, which is most commonly associated with NSCLC (up to 1/3 of patients) more than SCLC (only about 5%), and adenocarcinoma in particular. Here's what it looks like:

One of the basic concepts of oncology is that you treat patients with different drugs once they've shown progression on a treatment, rather than continue that a patient has presumably become resistant to. However, there are some exceptions to this: many or most women with breast cancer continue the antibody herceptin (trastuzumab) even after progression, adding it to one chemo and then the next, and the same is often done with avastin in colon cancer and sometimes lung cancer as well.

In my last post I wrote about the prognostic value of molecular markers like EGFR and K-Ras that have generally been studied in patients with advanced NSCLC and treated with EGFR inhibitors, but these studies looked at prognosis in patients with early stage NSCLC who underwent surgery. These studies also provided some interesting results on the prognostic value of some clinical variables as well.

We've seen clear evidence that patients who have tumors with certain mutations in the EGFR gene are highly likely to respond to oral EGFR inhibitors like tarceva (erlotinib) or iressa (gefitinib) -- with response rates that are in the 70% range and often last for many months or even a few years (see prior post).

One of the issues that we've commonly discussed and debated here is the question of when a local approach like surgery and/or radaition may be appropriate for I recently saw a patient of mine who I first met more than four years ago. At that time, he was only 37 years old and had just been diagnosed with stage IIIA NSCLC with several N2 nodes involved, after having quit smoking a couple of years earlier. He had actually initiated treatment with another local oncologist, a plan of chest radiation along with concurrent weekly carbo and taxol.

One of the principles of screening is that the likelihood of detecting a cancer depends greatly on the risk that a person being screen has for developing that cancer. Low risk means that it is very likely that any abnormality that is detected is more likely to be unrelated to cancer. And because of that, nearly all of the screening efforts thus far have focused on patients with a significant smoking history.

In prior posts I've described the special circumstance of a Pancoast tumor, which is a tumor at the top of the lung that tends to grow into the spine, ribs, and sometimes the nerves going to the arm. These cases are a major challenge because surgery is often something to consider, because they often grow locally more than speading to the rest of the body, but surgery can be a special challenge because the vertebrae are generally not considered to be resectable.

A quick point on the importance of biology over treatment. Years ago, I highlighted the results in the TRIBUTE trial of chemo with placebo or combined with erlotinib (tarceva) at the same time (biomarker study abstract here), which showed that patients with EGFR mutations had a much better survival whether they received an EGFR inhibitor or not: