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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June 19th, 2007 at 12:15 pm
I’ve left my history before, but wii repeat.
NSCLC in Dec 05, 7 wks of wkly carboplatin & taxotere plus daily radiation. Additional
chem & cancer free in April 06. 33 wkly
pleural effusions w/1200cc to 1500 cc. Have
family doctor, oncologist, cardiologist, pul-
monary doctor & 3 radiologist. Some recommend pleurodesis & others say no. My
fluid & blood tests, X-rays, C-T scan & Pet
scan all show negative for cancer.Some doctors think the fluid comes from cancer, but most think it is damage from radiation.
Would like your opinion & a discussion of
the effects if surgery is not successful. If
successful, where does the fluid go if the pleural sac is closed off. Thanks!
May 15th, 2007 at 4:42 pm
I believe that what they’re saying is that there isn’t just a free, open space where the fluid is collecting, but rather that there are loculated pockets of fluid that are not communicating with each other (closed off from each other). A Pleurx catheter can sometimes be used, but it’s a harder situation to manage than having one big open space with fluid in it.
-Dr. West
May 14th, 2007 at 9:36 pm
Dr. West, What is meant by complex fluids in respect to pleural effusions. My mom is experiencing shortness of breath during her second line treatment for lung cancer (actually MCUP). She had a small amount of fluid drained last week. The medical staff told us that they couldn’t drain any more fluid because it was complex fluids.She continues to be short of breath. Her regular oncologist is out for a few days. ARe there other methods for removing complex fluids? Thanks again for your time.
Jill
March 18th, 2007 at 8:54 pm
Yes, it would be concerning to see fluid that was very bloody (brighter red), but we typically see something in the range of what you’re describing, or sometimes without the rust, more of a clear or cloudy straw-colored fluid.
March 18th, 2007 at 4:53 pm
Dr. West,
My partner had a Pleurx catheter inserted 5 days ago, after having a thoracentesis about 4 weeks prior for his MPE. The fluid is a rusty tea color. Is that color of fluid to be expected?
Many thanks for this site, and the time you devote to it.
March 18th, 2007 at 4:03 pm
Yes, pleurodesis can be helpful, but it can also have complication. I’ll go over some of these issues in my next post.
-Dr. West
March 17th, 2007 at 1:07 pm
My wife had thoracentesis twice and then pleurodesis. Before the second thoracentesis she had a clean pet/ct (after radiation with taxotere)but the fluid tested positive for cancer cells. Just before the pleurodesis she had another ct scan to check for measurable disease to see if she was eligible for a trial as we agreed with the doctor she should have treatment considering the recurrent malignant pleural effusion. It surprised us that with nothing on the last petscan and a very recent ct scan with no measurable disease she still had a fast refilling effusion that necessitated pleurodesis. Pleurodesis was much more of an ordeal than we expected(8 days in the hospital as line clogged up unknown to anyone and second chest tube installed) and recovery took two weeks at home.
March 17th, 2007 at 11:24 am
Thank you both for your ongoing interest. Regarding Lisa’s questions, I don’t think bloodwork would be very reliably to rule in or rule out infection. And yes, while I would expect that inflammation following radiation wouldn’t be likely to appear 2+ years later, but especially with a minimal effusion, I think it still sounds fairly ambiguous. Besides, she’s now on treatment, so it sounds like she’s not getting a pat on the back and being told not to worry it (that may be partly in deference to your desire to be proactive). All in all, I’d say it’s certainly concerning, but the fact that she went a full two years without progression suggests to me that the overall pace of the disease may very well continue to be far slower than the general statistics.
I’ll just add that as Chanwit suggested, using symptoms related to a known pleural effusion, such as dyspnea, and the interval that a patient can go between taps for fluid removal, probably do provide a reasonable guide to what the disease is doing.
March 17th, 2007 at 8:17 am
Interesting article. I’m glad you touched on this subject. Mom’s latest CT just showed minimal pleural effusion. They are watching it. I’m not as laid back as the docs appear to be. Question: If it was due to infection, wouldn’t that be indicated somewhere in her blood work. Also, she hasn’t undergone radiation in 2.5 years, so can we rule out inflammation. More like than not, that would leave the effusion directly related to progression of cancer, correct? Don’t you think it’s probably time that this nasty disease has woken up and is starting to do its final dance. She is on Alimta after a two year progression free period. Still termed local recurrence. Tarceva didn’t work. Alimta was started a couple of months ago.
On behalf of everyone, thank you again for your efforts.
March 17th, 2007 at 7:59 am
This post takes me back to Feb. 2006 when my wife was DX in hospital with NSCLC with pleural effusion. The first oncology jargon I heard was “determine the primary source of the cancer” since it was metastatic. The resident hospital pulmonary doctor seem reluctant at first to perform the thoracentesis but it was done (not as quickly as the oncologist recommended). Clarifying that the pleural effusion was malignant was challenging as you hinted. The stains were Cytokeratin 7 & 20 strongly positive but the TTF-1, villin, WT-1 were negative. The impression was that the origin of the tumor remained unclear. That being done along with CT and MRI scans, presented her with the NSCLC dx. The initial color of the effusion was a fairly clear yellowish liquid. Months went by before additional effusion developed and with those taps the fluid had changed to a tea colored fluid. (comments). Her SOB and irregular breathing was how I judged that the effusion was recurring which prompted immediate doctor attention and eventual pleurodesis. In summary, if I had not detected the pleural effusion symptoms and had her treated, she would not have lived to receive Tarceva which was the drug designed with her genes in mind.
Dr. West, thanks for this information.
Chanwit