Study: Lymphedema Risk & Blood Draws, Injections, BP, Air Travel

Hi Binney4:

Thank you for posting this important piece. However, I do not read the blog post as saying that the conclusions of the study are faulty. Instead, Dr. Nudelman takes issue with the interpretations of the results made in commentaries and editorials written by third parties, and emphasizes that the failure to observe an association between increased arm volume and blood draws, etc. in this study does not equate with proof of safety of such interventions:

"The study concluded: "Although we cannot affirmatively state that risk-reduction practices have no effect on arm swelling, we hope to generate evidence that brings reasonable doubt to burdensome guidelines and encourage further investigation into non-precautionary behaviors and the risk of lymphedema. "

So, they didn't find that in the small numbers of their patients who recalled having medical procedures in their arms or flew without compression that they had a large increase in swelling of the part of their arms they could measure. But they couldn't definitively say it was safe."

In the passage above, she quotes a statement from the original article, in which they admit that the results do not prove that precautions are unnecessary, but hope they raise questions that warrant further investigation. Her remarks explain the authors' statement and note what it does not mean, but are not inconsistent with the statement. And while she notes certain weaknesses in study design, I do not think she is saying the author's conclusions are faulty. She is saying that the commentators have not interpreted the findings properly.

By the way, while it does not undermine her conclusions about safety, her remarks do not appear to be an accurate statement of the study design with respect to air travel. In particular, the assessment of air travel does not appear to have been based on recall, but per the original article was prospectively assessed:

"In our analysis, we prospectively collected information regarding air travel and quantified arm swelling with short intervals of follow-up. This design enabled the investigation of the immediate effects of flying on arm volume and minimized the risk of recall bias due to the shorter interval of follow up."

Dr. Nudelman emphasizes the importance of reading the original article to understand the study design, findings, what they do and do not establish, and the caveats and limitations. I could not agree more.

As I noted above, the full-text of the article is available for free to patients. Click on the full text option towards top right. Scroll down the page to the patientACCESS option at bottom. Follow the links. Registration with the Copyright Clearance Center is required, but the article is delivered at no charge via email in pdf format. I obtained a complete copy of the original full-length article in this manner at no charge:

http://jco.ascopubs.org/content/34/7/691

BarredOwl