Pleural Effusion

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Li Liu, MD
The Abramson Cancer Center of the University of Pennsylvania
Last Modified: November 1, 2001

Dear OncoLink "Ask the Experts,"
My father has been treated for non-small cell lung cancer. He did have surgery, Chemo, and radiation at the same time. Right now he has had fluid build up on the outside of his lung, and he has had 2 pints drained off, and there is more to be drained off. Our question, is this normal with Radiation treatment? We have been told that the fluid did not have any cancer cells in it.

Li Liu, MD, OncoLink Editorial Assistant, responds:

Thank you for your interest and question.

The differential diagnosis of pleural effusion (fluid build up in the chest) is very complicated. Normally the pleural fluid is formed primarily from the parietal pleura (which covers the surface of the chest wall diaphragm and mediastinum) and re-absorbed into lymphatics and visceral pleura capillaries (which covers lung surface). Any alterations of this formation-reabsorption mechanism will result in the accumulation of pleural fluid. Increases in water forces (seen in congestive heart failure) or decreases in suctioning forces (seen in low serum albumin level) in microvascular circulation result in "transudates". Increased leakage of the microvascular circulation (seen in pneumonia) or impaired lymphatic drainage from the pleural space (such as in malignancies) results in "exudates". The fluid in the abdomen (ascites) can also move into the chest cavity causing pleural effusion.

Radiation treatment rarely causes acute and large volume pleural effusion. For your father's case, cancer and infection need to be ruled out. Thoracentesis (draining fluid from chest) with a thorough pleural fluid analysis and radiologic examinations may provide useful information. Sometimes repeated thoracentesis and analysis are necessary to detect cancer cells in pleural effusions due to lung cancers.

You should talk to his oncologists regarding this situation.