Pleural effusions related to lung cancer are quite common, so it’s time that I discussed this issue. First, a pleural effusion is fluid outside of the lung, and it tends to follow gravity and pool at the bottom (base) of the lung, primarily along the back. Here’s how it appears on a chest x-ray, filling up the bottom of the left side of the chest. The right side, in contrast, is mostly black, which is the way lungs should appear on a chest-x-ray (but not in real life, we hope).
(click to enlarge)
However, pleural effusions can also be loculated, which means that they don’t follow gravity but rather are contained in pockets that are formed from scar tissue, inflammation, etc. Here’s a CT image showing a loculated effusion on the left side, not freely flowing in the chest to follow gravity:
A few starting points to make. Not all pleural effusions in the world are from cancer, and in fact, it’s probably just under half, with the balance being from infections and inflammatory reactions. Among the approximately 45% of effusions that are from cancer, lung cancer and breast cancer account for about 60%, with lung cancer as the leading cause (a little more than 1/3 of all malignant, or cancer-related, pleural effusions). They are important because the presence of cancer in the pleural fluid indicates systemic/advanced disease (although in SCLC the presence of a malignant effusion on the same side as the primary cancer is sometimes considered limited, and sometimes extensive, with no clear consensus), and because people can have symptoms of shortness of breath, cough, and sometimes pain from a pleural effusion, and relieving those symptoms is an important goal in managing lung cancer.
Clarifying that a pleural effusion is malignant can be challenging. Sometimes, the effusion is the first place people look to obtain a diagnosis of lung cancer, but we know that even in patients who ultimately are confirmed to have a malignant pleural effusion (MPE), it can be hard to find cancer cells in the fluid. This is usually done initially with a thoracentesis, which is a procedure in which a person has a needle inserted between the ribs in the back, sometimes under ultrasound or CT guidance, in an area where there is fluid beneath the skin, and fluid is then removed.
A thoracentesis can be diagnostic, which means it is being done to determine the cause of the fluid, for which usually only a syringe of fluid is removed, or it can be a therapeutic thoracentesis, in which the procedure is being done in order to remove as much fluid as possible to relieve symptoms for a patient, with sometimes as much as two liters of effusion fluid being removed.
The likelihood of finding cancer cells in the fluid from an initial thoracentesis is only in the 50-60% range. You can increase the chance of finding cancer of finding cancer overall by doing a second thoracentesis (or “tap”), but the likelihood of being successful the second time around after an initial negative tap is lower, in the 35-45% range. So it is possible to make a diagnosis of an MPE most but certainly not all of the time after 1-2 thoracenteses.
In cases where another source of tissue is not readily accessible, or if it is important for staging purposes to determine whether the pleural space is involved, thoracoscopy, or video-assisted thoracoscopic surgery (VATS), can be performed. This involves using a sterile tube with a light source and camera at the end that can go into the chest cavity through a small incision and get a look at what is happening. A surgeon can also take biopsies of suspicious tissue through the thoracoscope, and if necessary, can cut scar tissue and perform other manipulations through it. A picture of studding of the pleural space with tumor is shown here (cover the screen and don’t enlarge if you’re squeamish — this is a surgery picture!):
Thoracoscopy can get a diagnosis more than 95% all the time. And while VATS is only a small, relatively minor surgery as far as chest surgery goes, it can still have complications such as bleeding, infection, or pain, usually in <10% of cases, and there are rare deaths (<2%). The VATS procedure, but the way, is the same general approach that is sometimes used to perform a lobectomy by specially trained thoracic surgeons, and that's a topic I'll discuss separately in the near future.
Once you have a diagnosis, managing the fluid buildup is another major issue to tackle. For some responsive cancers, such as lymphomas and SCLC, systemic therapy (such as chemo) is often enough to also treat the effusion. Some breast cancers, and also some NSCLCs as well, may be responsive enough to systemic therapy to not require additional interventions. However, many MPEs continue to recur and have significant symptoms associated with them. I’ll discuss the more common ways to drain and manage the fluid collections next.
posted by Dr. West @ 3:30 am link to this post
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April 7th, 2008 at 9:39 pm
Neither atalectasis nor pneumonitis is necessarily caused by obstruction. Atalectasis is a local area of lung collapse, and that can be from justt not getting enough air in to inflate all of the lung areas. Pneumonitis is inflammation that really is caused by some irritating factor against the lung tissue, such as radiation causing a burn effect, or chemo possibly causing something like a chemical burn in lung tissue. But it’s not an obstruction.
-Dr. West
April 6th, 2008 at 4:16 pm
How does pneumonitis differ from Atalectasis? From your description in your response to TomP (reply #27) it sounds like the same thing to me. Am I correct to assume atalectasis is caused by an obstruction, such as a tumor or lymphadenopathy, whereas pneumonitis is caused by obstruction secondary to swelling and/or mucus production as a result of inflamation?
April 5th, 2008 at 11:08 pm
The radiologist’s report called it post-obstructive pneumonitis and the more I read about post-obstructive, the more I mistakenly guessed pneumonitis was an infection caused by the lack of air.
So down the line if alimta/radiation doesn’t work, will try to find a skilled pulmonologist in Arizona willing to try the laser or stent procedures. Thanks.
Thanks for info on GRACE and donating.
April 5th, 2008 at 9:10 pm
Pneumonia isn’t the same as pneumonitis. Pneumonia is an infection in the lung tissue, while pneumonitis is inflammation, potentially caused by prior chemo or radiation. The idea of post-obstructive pneumonia is that if you close off an airway, you have a moist sponge of lung tissue that isn’t getting aerated, and it becomes basically a set-up for infection. A moist, isolated and enclosed area of lung tissue becomes like a petri dish.
The process of a lung area closing off isn’t typically sudden. It just gradually gets less air, so someone can just have gradually more cough, less oxygen, and develop recurring fevers. Antibiotics can help, but if you’ve still got an enclosed lung that isn’t getting air, it remains a set-up for ongoing infection. The main ways we try to treat this are to give radiation to shrink the obstructing tumor and thereby open the airway, or a pulmonologist can go in, try to use a laser or similar approach to destroy tumor tissue in a bronchial tube from the inside, or sometimes put in a stent to prop open an obstructed bronchus during bronchoscopy. Chemo can also potentiallly shrink an obstructing tumor too, but it doesn’t tend to be as reliable or quick as radiation or some other mechanical, local intervention.
Thanks for your very kind words here and on the guestbook. Since you asked, I’ll mention that OncTalk is being overseen and supported by a nonprofit called GRACE, the Global Resource for Advancing Cancer Education, that I lead (but the money will go toward other people, not me — I’d rather have the network grow and the entity really succeed). GRACE will allow us to enlist the help of other experts, growing from just a one doctor experience. GRACE can absolutely benefit from donations from you and others who would be so inclined — the money will directly sponsor increased faculty to help broaden educational offerings and provide additional points of view. Here’s where you’d find info on donating:
http://cancergrace.org/donate/
MANY THANKS.
We’re moving over to the new GRACE website very soon.
-Dr. West
April 5th, 2008 at 4:50 pm
Thanks, Dr West, I’m clear that the p/o pneumonitis is from my tumor closing off my right lobe bronchials, thus creating an environment conducive to infection. Is pneumonitis the same as pneumonia? Someone told me 2 yrs ago I’d probably die of pneumonia from a collapsed lung due to the tumor’s location. Scans show no metastases so I won’t worry if I have MPE for awhile.
Maybe this Q should be in another section but could you give me and others in this situation a description of what happens when a lobe closes off, is it sudden, what can be done, when one lobe goes, they all go?, etc? It seems I’ve heard that pulmonologists can put a lobe out of commission, empty it and close it off and their emphyzema patients live off the remaining lungs’ capacity.
I’ve never appreciated a service as much as yours. Believe me, if I could get responses from my docs, I would.
April 5th, 2008 at 10:51 am
Tom,
There isn’t a clear reason to check the fluid for cancer cells if a patient already has advanced/metastatic disease, because it won’t change staging or treatment. There may still be a value in doing a thoracentesis to relieve shortness of breath, but if someone has liver or bone metastases, for instance, there wouldn’t be a reason to send fluid to look for cancer cells. On the other hand, if a patient with otherwise stage I -III lung cancer and a pleural effusion is undergoing initial staging or has received treatment, it’s helpful to check if the fluid is from the cancer or some other cause, such as pneumonia or heart failure.
It’s not the case that having a malignant pleural effusion (MPE) increases the risk of cancer spread, but rather that it is an indicator that there are micrometastases in the bloodstream. It’s an effect rather than the cause. MPE, or “wet IIIB” NSCLC is therefore an index of advanced NSCLC and is treated by the same standards as metastatic disease.
And the post-obstructive pneumonia would be caused by a solid mass, not the effusion.-
-Dr. West
April 5th, 2008 at 12:26 am
Thanks for so much info on pleural effusion. After 2 yrs of CTs and PETs, a Feb report for the 1st time mentions “development of postobstructive pneumonitis in the right upper lobe” where my 4.4 cm tumor is. Also there is a new “5 cm loculation of pleural fluid anteriorly and superiorly”. Receiving 2nd time radiation and alimta and tolerating it reasonably well. Could I get an idea of when they should be checking if the pleural fluid is malignant? I do get more pain & shortness of breath now. I know you mentioned that draining the fluid relieves some symptoms but doesn’t the fluid also increase the chance of metastasis significantly? Will I have to wait until the daily radiation treatments are over before thoracentesis? Is the “p/o pneumonitis” in any way related to the pleural fluid? Thank you so much for the help you’re giving us and my thoughts go out to all of you.
February 17th, 2008 at 8:44 pm
We’re going based on good judgment alone rather than any rules here, but that sounds very reasonable to me – something in the 2-4 month range would be enough to see some meaningful change in one direction or another.
-Dr. West
February 17th, 2008 at 6:30 am
Many thanks Dr. West. I suspect that a follow-up scan will be where we go (even though the waiting is difficult). Would three months be a reasonable interval?
February 16th, 2008 at 2:36 pm
Cal,
It’s certainly possible for inflammation, such as post-radiation effects, to lead to a small to moderate pleural effusion. The pleural-based nodules are harder to explain away and are particularly suspicious for progression, I agree, although I would consider it still quite possible to see this as part of a vey vigorous inflammatory response after chemo and radiation.
Distinguishing a malignant from a non-malignant cause could be achieved by having a thoracic surgeon to a thoracoscopy and look directly in, likely taking biopsies of pleural-based nodules to confirm the diagnosis, or refute it. However, a follow-up scan would likely give that information non-invasively — you’d expect inflammation to show improvement over time, but cancer would show increasingly prominent abnormalities with each subsequent scan.
-Dr. West