Surreal illustration of CSF leak after lung cancer treatment.

Unmasking a Rare Side Effect: How Lung Cancer Treatment Can Trigger Spinal Fluid Leaks

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Lena Voss in Health & Wellness December 2025 • 4 min read.

"Discover the unexpected link between Erlotinib, a targeted chemotherapy for metastatic lung cancer, and the risk of cerebrospinal fluid leaks, offering insights and guidance for patients and healthcare providers."


Cerebrospinal fluid (CSF) rhinorrhea, characterized by the leakage of spinal fluid from the nose, is a rare but recognized complication following medical interventions for pituitary tumors. However, a less familiar scenario involves CSF leaks arising after targeted medical treatments for metastatic cancers affecting the skull base. This article aims to shed light on such an unusual case, emphasizing the importance of awareness and vigilance among both patients and healthcare professionals.

Imagine a treatment designed to shrink a tumor inadvertently creating a pathway for spinal fluid to escape. This is precisely what occurred in a unique case involving a 66-year-old woman battling Stage IV lung adenocarcinoma. After undergoing systemic erlotinib chemotherapy, she developed a CSF leak, leading to a cascade of complications.

Erlotinib, an epidermal growth factor receptor (EGFR) inhibitor, is a targeted therapy commonly used in non-small cell lung cancer treatment. While effective in shrinking tumors, its use can sometimes lead to unexpected side effects. This article delves into the specifics of this case, revealing how tumor regression following erlotinib treatment can, in rare instances, create conditions favorable for CSF leaks.

The Case Unveiled: Erlotinib and the Unexpected Leak

Surreal illustration of CSF leak after lung cancer treatment.

The patient, diagnosed with EGFR-mutant Stage IV lung adenocarcinoma, initially responded well to erlotinib chemotherapy. A large sellar and clival lesion, indicative of metastatic disease, showed signs of regression. However, approximately one week after starting treatment, the patient began experiencing clear discharge from her right nostril.

Initially misdiagnosed as allergic rhinitis, the discharge was later identified as a CSF leak following a bout of meningitis. Further investigation revealed an erosion of bone and dura at the dorsum sellae, a consequence of the tumor's regression due to chemotherapy. This erosion created a pathway for the CSF to leak.

  • Diagnosis Delay: The initial misdiagnosis highlights the need for increased awareness of this potential complication.
  • Meningitis Risk: The development of meningitis underscores the severity of untreated CSF leaks.
  • Endoscopic Repair: The patient underwent successful endoscopic repair of the leak, emphasizing the importance of timely intervention.
The patient's case underscores a critical point: CSF leaks can occur following systemic chemotherapy, particularly when the treatment leads to significant tumor regression. While erlotinib effectively targets and shrinks tumors, this process can inadvertently expose pre-existing weaknesses in the skull base, leading to CSF leakage.

Key Takeaways: Awareness and Vigilance are Crucial

This unusual case highlights the critical need for heightened awareness among oncologists, neurologists, and other healthcare providers involved in the treatment of lung cancer. When patients undergoing systemic chemotherapy, especially with agents like erlotinib, present with symptoms such as persistent nasal discharge, a CSF leak should be considered as a possible cause.

Early diagnosis and prompt intervention are essential to prevent serious complications like meningitis. A thorough evaluation, including testing the nasal discharge for beta-two transferrin, can help confirm the diagnosis. Endoscopic repair offers an effective solution for closing the leak and restoring the integrity of the skull base.

While CSF rhinorrhea remains a rare complication of erlotinib treatment, understanding the potential link between tumor regression and spinal fluid leakage can empower healthcare professionals to provide timely and effective care, ultimately improving patient outcomes. The medical community must be vigilant.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.wneu.2017.08.183, Alternate LINK

Title: Cerebrospinal Fluid Leak Rhinorrhea After Systemic Erlotinib Chemotherapy For Metastatic Lung Cancer: A Familiar Problem From An Unfamiliar Culprit

Subject: Neurology (clinical)

Journal: World Neurosurgery

Publisher: Elsevier BV

Authors: Blake Priddy, Douglas A. Hardesty, André Beer-Furlan, Bradley Otto, Daniel M. Prevedello

Published: 2017-12-01

Everything You Need To Know

1

What is Erlotinib, and why is it relevant to this topic?

Erlotinib is a targeted chemotherapy drug, specifically an epidermal growth factor receptor (EGFR) inhibitor, used to treat non-small cell lung cancer, especially in patients with EGFR mutations. Its significance lies in its ability to shrink tumors. However, as seen in the case, tumor regression following the use of Erlotinib can create conditions that lead to Cerebrospinal Fluid (CSF) leaks.

2

What is a Cerebrospinal Fluid (CSF) leak, and what is its significance in relation to the treatment discussed?

A Cerebrospinal Fluid (CSF) leak is the abnormal leakage of spinal fluid, typically from the nose (CSF rhinorrhea). In the context of Erlotinib treatment for lung cancer, it's significant because the tumor regression caused by Erlotinib can erode bone and dura in the skull base. This erosion can create a pathway for the CSF to leak, leading to complications like meningitis. This emphasizes the importance of awareness and vigilance among healthcare professionals.

3

What is the significance of meningitis in this scenario?

Meningitis is a serious inflammation of the protective membranes covering the brain and spinal cord. The risk of meningitis is heightened when there is a Cerebrospinal Fluid (CSF) leak because the leak provides a direct pathway for bacteria to enter the central nervous system. In the case described, the patient developed meningitis following the CSF leak, highlighting the importance of recognizing and treating CSF leaks promptly to prevent such severe complications.

4

Why was the delay in diagnosis important?

The patient in the case experienced a delay in diagnosis, initially misdiagnosed as allergic rhinitis. This highlights the importance of considering a Cerebrospinal Fluid (CSF) leak as a possible cause of nasal discharge in patients undergoing chemotherapy, particularly with Erlotinib. Early recognition and diagnosis of a CSF leak are critical because they can lead to prompt treatment, preventing severe complications, such as meningitis.

5

What are the implications of Erlotinib potentially causing Cerebrospinal Fluid (CSF) leaks?

Erlotinib, while effective in treating lung cancer, can cause unexpected side effects, such as Cerebrospinal Fluid (CSF) leaks. The implications of this are that healthcare providers need to be aware of this potential complication when treating patients with Erlotinib. Vigilance is required, and any unusual symptoms, like persistent nasal discharge, should prompt investigation. This will help prevent potential complications such as meningitis, through early detection and intervention like the endoscopic repair of the leak.

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