GRACE :: Lung Cancer
Dr West

Pneumonic BAC: The Subtype Very Unlike Other Forms of BAC

Share
download as a pdf file Download PDF of this page

One of the issues with BAC is that I’ve referred to it as potentially very indolent, but as we’ve learned more about BAC, it’s become clear that there is a great degree of heterogeneity in BAC cases. We’re learning that the cases that are more often slowly progressing and sometimes exceptionally responsive to EGFR inhibitors like tarceva and iressa are far more likely to be non-mucinous BAC. These typically have the appearance of innumerable small nodules throughout the lungs. There is a form that is the opposite: with sweeping areas of consolidation (also known as opacity) throughout entire areas of lung, typically mucinous, and essentially never responsive to EGFR inhibitors based on what we know right now. This form is called pneumonic BAC, and it is typically very aggressive and unfortunately seems to be resistant to most of our treatments.

It’s called pneumonic BAC because it looks for all the world like pneumonia on an x-ray or CT, and I suspect that just about every patient who is ultimately diagnosed with pneumonic BAC is treated for at least weeks and often months with antibiotics. The classic example is that it involves much or sometimes all of a lobe of the lung:

Pneumonic BAC

Because it’s mucinous BAC, these patients often describe coughing up large amounts of frothy sputum.

The case above shows involvement in both lungs, so surgery wouldn’t generally be performed (although it’s sometimes done even palliatively to relieve the productive cough and shortness of breath, since blood runs through this part of the lung and gets no oxygen), but in cases that have involvement of an entire lobe that go to surgery, we sometimes review the cases in a tumor board. Unfortunately, these are cases in which we often see them develop recurrences within months. It’s not clear whether chemo leads to a lower risk of recurrence.

As I mentioned above, the limited analysis we’ve done of mucinous vs. non-mucinous BAC in trials of EGFR inhibitors like iressa and tarceva have shown that responses seem to be essentially limited to the patients with non-mucinous BAC. My colleagues from Memorial Sloan Kettering Cancer Center in NYC have been doing molecular testing on a lot of lung tumors they’re treating, and they’ve told me that these pneumonic BAC cases very often have K-Ras mutations, which goes with a lack of benefit from EGFR inhibitors.

We don’t know whether any systemic therapy works for these patients, but I’ll describe a clinical case in the next few days that illustrates typical course. In the meantime, the take home message is that while some BAC lesions grow incredibly slowly and are responsive to many treatments, others are very different. I think very few oncologists know the difference, but the pneumonic BAC cases are ones that are typically very aggressive and respond rarely if ever to the oral EGFR inhibitors.


10 Responses to Pneumonic BAC: The Subtype Very Unlike Other Forms of BAC

  • melissa says:

    Dr. West,

    My husband has Signet Ring cell lung cancer. Is there any study associated with this type of lung cancer?

    Thanks.

    Melissa

  • Dr West
    Dr. West says:

    I would consider signet cell subtype to be completely different, and frankly, I’ve never treated that, or even heard anything about it specifically. I would be inclined to basically use trial and error with the typical treatments to see what works, since I don’t think we have any meaningful prior experience to go on.

    -Dr. West

  • Jolene says:

    Thank you for the post above. My dad also had BAC which was the mucinous form. He was Dx with pneumonia several times before it was Dx by a bronch due to unresolved pneumonia. He has been gone two years and I appreciate the research that is being done in regards to BAC.

    My dad had problems with breathing for several years prior to his Dx. He called it “allergies” and the cold made it worse. It appears that the form he had is quite aggressive, yet, I think he surely had it longer that anyone knew. Is it possible that he had it for several years? He suffered one full year going to allergists, etc. trying to figure it out. So actually, with the foam and mucous he spit,
    he lived almost 20 months, but lived only 8 months after Dx. Thanks Jolene

  • Dr West
    Dr. West says:

    Jolene,

    I think many patients have a long latency between a scan that looks for all the world like pneumonia (and with essentially completely overlapping symptoms) and an ultimate diagnosis, and that’s often after months or a year or more of these symptoms.

    I just saw a patient with this form who has had it grow for somewhere in the range of 12-18 months before his diagnosis, but it went from significant to overwhelming in that time.

    I think there are two key issues. The first is the rate of progression, which may have the potential to be very aggressive but often isn’t. In fact, it may be somewhat slow by lung cancer standards. But I don’t think it’s as exceptionally slow as some non-mucinous BAC cases are, in whom you need to follow some nodules over years to detect progression. If mucinous BAC takes several months to show progression, that’s faster than many BACs, but it’s not breaking any records for lung cancer in general.

    The second issue is response to treatment. What has really raised the visibility of BAC over the past few years has been the growing awareness that it’s often patients with BAC who have the staggering responses to oral EGFR inhibitors like tarceva and iressa: these are just more impressive and often longer lasting than anything we used to see in lung cancer (short of surgery removing the cancer). With that, and several trials dedicated to studying EGFR inhibitors in BAC (including a large one that I led), many oncologists now consider an EGFR inhibitor to be the preferred first line treatment for BAC. However, a point I’d make is that when we take a closer look, it seems like nearly all of the favorable activity for these agents in BAC is actually in folks with the non-mucinous form. I don’t know that there’s any activity of them in mucinous BAC and now would definitely not be inclined to use them as my front line approach. I have some very limited experience that leads me to believe that chemo +/- avastin can be active in mucinous BAC (although not the same kind of responses you see with EGFR inhibitors in some BAC cases); I don’t know if it’s the chemo alone, the avastin, or the combination that has led to the activity I’ve seen.

    These cases are few and far between. I’d consider myself one of the people most interested in BAC in the whole country or world, and I only see 1-2 patients with mucinous BAC a year. Most oncologists probably see 2 or 3 in a decade or more. The point is that it’s hard to get a good read on any patterns when you’re seeing so few people who fit in the category. But we’re learning what we can pretty quickly.

    -Dr. West

  • Paula C. says:

    Dr.West, If Iressa doesn’t help a patient, besides chemo what other options are there? My dad has mucinous BAC, it’s very aggressive and very advanced. Have you seen a patient in your work who was had a very advanced case be able to sustain some length of survival? If so, what are the options if Iressa doesn’t work? Thank you

  • Dr West
    Dr West says:

    Unfortunately, other than a trial of an EGFR inhibitor like Iressa or Tarceva, and perhaps a trial of single agent chemotherapy, options are pretty limited. Some cases of mucinous, particularly pneumonic BAC are so relentless and resistant that I’m not sure that there is anything on earth that will make a meaningful difference, at least nothing we know about right now.

    However, beyond EGFR, there is a chance that some people with mucinous BAC will harbor an ALK rearrangement that can be tested for (there are labs that do this specific test), and if that were positive, the oral agent crizotinib would often be VERY helpful, and the chemo agent pemetrexed (Alimta) might also be useful (some studies suggest it has particular activity in ALK-positive lung cancers). I understand that he may be very debilitated, but single agent Alimta is among the better tolerated chemotherapy approaches.

    -Dr. West

  • Craig says:

    For the benefit of others who read this article in the future, I’ll add that Xalkori (crizotinib) could be a promising option for not only ALK-driven m-BAC but also m-BAC driven by the more newly-researched ROS1 muation. The well-known patient Linnea’s ALK-driven m-BAC responded exceptionally well to that drug, and my ROS1-driven m-BAC/adeno responded well, too.

  • lennymara says:

    Dr. West, My mom (71) had recurrent pneumonia for 10 months and since December DX mucinous AIS with BAC behavior stage IV. She has Kras and CDKN2A mutations, 6.5 lower left lobe and 3.5 lower right lobe tumors and of course other small nodes and multifocal ground grass opacities. After 2 cycles of Alimta and carboplatin, tumors remain stable but not shrinking. Treatment is affecting her overall health with strong anemia, recurrent pneumonia after each cycle, strong cough, brain chemo, deaf, body tremors, terrible grey shade in her skin and others. Before chemo my mom was fine just got sick whenever was exposed to AC, now she feels like slowing dying. Is there any treatment or trial somehow effective for mucinous BAC with this kind of mutations? I don’t feel chemo is going to help or even worst it is going to kill her before the cancer. We want to stop chemo but we don’t know what else to try. Please, help me!

  • lennymara says:

    I forgot to say she also has 25%PDL1 staining.

  • Dr West
    Dr West says:

    I’m sorry to hear she’s having such a difficult time. The short answer is that I’ve already posted all of my thoughts on the GRACE website. chemotherapy is the cornerstone for patients who don’t have a driver mutation like EGFR, ALK, or ROS1. It’s reasonable to try immunotherapy — that’s pretty close to an unknown for mucinous BAC, but my limitation experience with it in patients with mucinous BAC hasn’t been especially favorable.

    Good luck.

    -Dr. West

Leave a Reply

Ask Us, Q&A
Lung/Thoracic Cancer Expert Content

Archives

Share
download as a pdf file Download PDF of this page

GRACE Cancer Video Library - Lung Cancer Videos

 

2015_Immunotherapy_Forum_Videos

 

2015 Acquired Resistance in Lung Cancer Patient Forum Videos

Share
download as a pdf file Download PDF of this page

Join the GRACE Faculty

Breast Cancer Blog
Pancreatic Cancer Blog
Kidney Cancer Blog
Bladder Cancer Blog
Head/Neck Cancer Blog
Share
download as a pdf file Download PDF of this page

Subscribe to the GRACEcast Podcast on iTunes

Share
download as a pdf file Download PDF of this page

Email Newsletter icon, E-mail Newsletter icon, Email List icon, E-mail List icon

Subscribe to
GRACE Notes
   (Free Newsletter)

Other Resources

Share
download as a pdf file Download PDF of this page

ClinicalTrials.gov


Biomedical Learning Institute

peerview_institute_logo_243