Cancer staging is an important clinical tool. At the very least, agreement on a staging system allows us to compare treatment regimens and choose the best one for our patients. But classical staging—based on anatomical and pathological criteria as in the TNM system–doesn’t always predict response to treatment.

Modern genotyping techniques offer an alternative to classical staging. In the latest issue of The New England Journal of Medicine (356(1), January 4, 2007), a group of researchers from Taiwan report on a using gene signatures for determining clinical outcome in non-small cell lung cancer (NSCLC) (Chen, HY et al.: A five-gene signature and clinical outcome in non-small cell lung cancer).

The Taiwan group used microarrays to look at some 672 genes that were associated with invasive activity. They fine-tuned their analysis to identify 16 genes that were associated with survival and further reduced the set to five genes that were “independent predictor[s] of relapse-free and overall survival.” The researchers note that using PCR techniques with a small set of genes can be a practical clinical test.

For example, the authors note that “cisplatin-based adjuvant chemotherapy is effective in some patients with NSCLC. We propose that patients who have tumors with a high-risk gene signature could benefit from this type of adjuvant therapy, whereas those with a low-risk gene signature may be spared what would be unnecessary treatment.” The side-effects of cis-platin, as many of you know, can be quite unpleasant.

I’ll admit the actual article—especially the methods section—was rough sledding. Much of the vocabulary of modern genetic medicine is foreign to us who were in med school 25 or more years ago. But the fact remains that genetic medicine is becoming an ever greater part of modern medical practice, and it behooves us all to become familiar with its principles.

I’ve posted on this general topic elsewhere in the blog, including here and here.

Technorati Tags: cancer staging, non-small cell lung cancer, microarrays, gene signatures

The Uncertainty Principle

It’s been ninety-four days since I had coronary artery bypass surgery.  I feel fine.  Truly, the only reminders of the surgery are an impressive scar down the middle of my chest and somewhat shorter chest hair.  I’ve also started back to part-time work as a doctor.

I was worried when I started back that I might be a bit rusty.  Fortunately, that hasn’t been the case. But there’s one thing I forgot during my six-month break from practicing clinical medicine (I retired from my medical group at the end of May)—I’d forgot just how much uncertainty is involved in the practice of medicine.

In a general medical practice, most of the patients we see have well-defined problems, such as high blood pressure, carpal tunnel syndrome, shingles, backaches, and the common colds of either medicine (a virus) or psychiatry (depression).  But in the mix of cases there are also a number that defy classification either because the diagnosis is unclear or because the treatment involves too many variables. Read the rest of this entry »

Many years ago Uncle Sam sent me to Rockford Illinois to repay my National Health Service Corps scholarship by providing medical services to the medically indigent population of Winnebago County. Rockford population about 150,000 was the second largest city in Illinois and, to this California boy, rather provincial.

At the time I arrived, the HIV epidemic was raging. In Rockford, most of the victims were iv drug users, their partners, and their children. HIV wasn’t really a gay thing in Rockford because when a gay Rockfordian was old enough to leave town, he did—usually for Chicago.

Faced with the epidemic, I asked my Rockford colleagues why no one had started a needle exchange program. “Oh,” I was told, “we can’t do that here. Rockford is a conservative town…”

But I digress.

Rockford is in the medical news big time this week because of a study just published in the December 15 issue of The New England Journal of Medicine . The study looked at colonoscopies performed by twelve gastroenterologists practicing in Rockford. The main conclusion of the study was that the longer the gastroenterologist took to do the colonoscopy, the more likely he was to find an advanced neoplasm—a polyp that showed precancerous changes.

The immediate result of this will be for every gastroenterologist who performs colonoscopies to slow down! Colonoscopy is considered the gold standard of screening tests for colorectal cancer. Colonoscopy is more likely to find a neoplasm than simple sigmoidoscopy, which only looks at part of the colon. Colonoscopy is also considered more sensitive for finding early neoplasms than is fecal occult blood testing. And in recent years, both “virtual colonoscopies” (colonoscopy by helical CT scanning) and tumor DNA screening of stool have been proposed as alternatives.

The DNA screening test is apparently very sensitive—88%–for all stages of colorectal cancer and is entirely non-invasive. Results of a trial of the test will be published in the January 2007 issue of Clinical Gastroenterology and Hepatology.

To return to Rockford, I want to add that I was treated very well during my time there. The local medical community was welcoming and helpful. I had many opportunities to stay on in Rockford. But I’m a California kid.

Technorati Tags: colon cancer, colon cancer screening, colonoscopy, New England Journal of Medicine, Rockford IL, HIV, DNA test for colon cancer screening

It’s toward the end of the year and I’ve been making sure that I have enough Category I units of continuing medical education to satisfy the California licensing requirement. Just to be sure, I took a couple of the New England Journal of Medicine’s on-line CME tests. This forces me to dig into the ever-growing stack of journals about which I keep telling myself I’m going to get around to. Anyhow, when completing the test on Peginterferon and Ribavirin for Chronic Hepatitis C (NEJM 2006;355:2444-51) I happened to glance over at the “notices” page and a reference to the University of California Genetics of Absolute Pitch Study.

Absolute pitch is the same as perfect pitch, and there us some good preliminary evidence that this trait runs in families an likely has at least a partial genetic basis. The Absolute Pitch Study’s Web site seeks to recruit subjects. The site includes an auditory test—you can hear the tones through your computer’s sound card.

Alas, I don’t have perfect pitch, but I do have one of those nifty little electronic tuners that clips onto the peghead of my guitar!

Technorati Tags: music, perfect pitch, genetics of music, university of California, San Francisco

Follow this link to the excellent Genetics and Health site to read about yet another study showing that pharmocogenetic testing is valuable in choosing the best antidepressant therapies.

This is from Genome Web News, a subscription service. Registration is free, but some of the items require a fee. The following is freely distributed. You can register at http://www.genomeweb.com/

————————————–