Dr. West -

Many thanks to you and to Dr. Djang for a very clear and informative podcast.

I’ll have my first post-chemo scan following my next treatment (fourth session of Taxol/Carboplatin/Zometa) which occurs at the end of this week. My oncologist has not yet decided on CT or PET for that scan, but we’ll be discussing it soon. Your podcast has given me a better understanding of the benefits of PET so I can ask more informed questions during that discussion. Based on Dr. Djang’s comments, I tend to favor a PET scan this time, but will listen carefully to my oncologist’s rationale for either approach.

- Catharine

This podcast answered many of my questions about PET scans. I’ve been taking them regularly for almost three years. What I found most interesting is how changes in SUV are initially more indicative of cancer activity than tumor size.

The role of PET scans in following response to treatment remains a grey area compared with staging, where PET scans have become a remarkably helpful tool. I don’t routinely use PET scans for following advanced disease, where a CT 6-8 weeks after starting treatment can still do a very good job of telling us about whther a cancer is responding, stable, or progressing.

While it’s true that a PET scan can potentially be more sensitive than a CT at detecting subtle changes, I’m wary about making treatment decisions too rapidly based on changes that may be too subtle. If we see the SUV rise from 6 to 8 but the size of a tumor remains stable, I’d be very reluctant to just declare the treatment to be a failure. We don’t have so many very effective treatments for lung cancer that I’d want to have too low a threshold to change treatments if the differences are so subtle that they can’t be detected on a CT scan. My general feeling is that if it’s so subtle that a CT doesn’t show changes, it’s too subtle to alter treatment decisions.

There are still some situations in which I’d use a PET scan to follow disease, and I don’t think it’s wrong to use it more frequently, but Dr. Pennell has also expressed his belief that PET scans are overused in advanced lung cancer, and many other experts feel similarly. It’s a place where there’s still room for different strategies.

-Dr. West