BAC?

[raneyf]

Can someone educate me about the BAC type of NSCLC? I know I have adenocarcinoma. Is BAC a further subtype of this or something completely different. These probably would have been good questions for my oncologist, but I didn't think of them until now. I appreciate any information.

Thanks,

Raney

[mary colleen]

"BAC" is Broncheoalveolar Carcinoma, and is a subset of Adenocarcinoma. Most of the medical literature on the targeted therapies (like Tarceva) suggests that BAC is more likely to be responsive to those meds than other types of LC are.

[Andrea]

If you have adenocarinoma, you may not have BAC. BAC is a subset of NSCLC and a rarer type of adenocarcinoma, but it acts very different than most NSCLCs. The oncologist said BAC is very very slow growing, it typically appears as multiple spots, and Tarceva is usually the drug of choice.

The good thing about BAC is how slow growing it is, the bad part is that it is not as responsive to traditional chemo.

[DrWest]

Although I specialize in lung cancer in general, my greatest particular interests are BAC and never-smokers with lung cancer. I have posted a few general topics on BAC on my blog thus far, available through this link:

http://onctalk.com/category/lung-cancer ... ancer/bac/

I am planning to add a good bit of additional information about BAC and also never-smokers with lung cancer on this site over the next several weeks and months.

I hope this information is helpful.

-Jack

[mary colleen]

Dr.West - I am just a relative newcomer here, but I appreciate your posting and providing us another informational link. From my standpoint, this is a tough diagnosis to navigate through, and requires all possible help. Though I feel that my husband has a very diligent and capable oncology/surgical/pulmonary team, I want to be as informed as possible in order to support him in his effort to get well. I personally welcome any and all help! Happy Thanksgiving!

[blaze100]

My BAC tumor was very large and confined to one lung...and hopefully it's gonna stay that way.

I read someplace that BAC was identical or very similar to a virus carried by some European sheep.

I can't understand why young never smokers get BAC and more women than men, but I wonder if it could be a virus?

Barb

[raneyf]

So it seems as though it would be strange to have bone mets with BAC, since it's slow growing and such? Is that everyone else's understanding also?

[john]

I believe that there is a "pure" BAC which will usually stay confined to the lungs and adeno with BAC features. So there are different forms of BAC

Cancer mutates all the time I believe so I guess it is possible for the cancer to change somewhat.

There is a mutation that is found in cancers that make Tarceva not work.

[john]

Dr West what do you think of the irreversible EGFR inhibitors? Does the latest trials look promising?

[DrWest]

To respond to the question of bone mets from BAC, pure BAC, which is far less common than the mix of adeno with BAC features, can't invade tissues and just grows in the lungs, like moss, or a coating of paint over the thin lining that gas moves through in the lungs. Covering that lining means that oxygen can't get through, and the lung area involved doesn't work well. Regular adenocarcinoma is invasive and can spread to bones, brain, liver, and other places. If a cancer was said to be BAC but had spread outside of the lungs, I would conclude that it had to be a mixture of adenocarcinoma and the non-invasive BAC form. That mix accounts for something like 15-20% of all NSCLC. Importantly, the trials we're running for BAC allow patients not only with pure BAC but with the adeno+BAC mix to participate, and the trials thus far show that the ones with the mix are just as likely or more likely to do with with drugs like Iressa and Tarceva than patients with pure BAC.

If you want some pictures or more detail, I have a summary of the spectrum from pure BAC to invasive adenocarcinoma here:

http://onctalk.com/2006/10/11/defining- ... ne-end-of/

As for the question of irreversible inhibitors, I'm doing a trial with one of them (Wyeth's drug HKI-272) at my own institution, but it's too early to say whether they add anything beyond what tarceva can do (and I'm bound by a confidentiality agreement not to divulge inside information about the trial before it's publically available). Some test tube studies suggest they may be helpful in some folks, like those who previously responded to Iressa or Tarceva and then had the cancer progress, but we're still gathering information from the trials in real people.