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HomeHealth articlespneumonia in lung cancerWhat Is the Effect of Pneumonia on Lung Cancer?

Pneumonia in Lung Cancer- Causes, Complications, Diagnosis, and Treatment

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Lung cancer itself is a life-threatening condition. In addition, when infections like pneumonia occur along with lung cancer, it worsens the issue. Read below.

Medically reviewed by

Dr. Rajesh Gulati

Published At March 13, 2023
Reviewed AtJuly 11, 2023


Pneumonia, along with lung cancer renders a patient's life span questionable, especially in an advanced stage of cancer. In most cases, pneumonia occurs after lung cancer has been diagnosed. But there are clinical conditions that present as pneumonia in patients and they are later diagnosed with lung cancer. Either way, both can complicate the patient’s condition.

What Is Pneumonia?

Pneumonia is an infection caused by any organism, like bacteria, fungi, or viruses. It is a condition that infects the air sacs in the lungs and fills them with fluids or pus, causing cough with phlegm or sputum. It can occur in any age group, from newborns to older adults.

What Is Lung Cancer?

An abnormal growth of cancer cells in the lung results in the formation of tumors or masses is called lung cancer. It usually occurs due to cancer-causing agents present in the smoke of vehicles, cigarettes smoking, etc. Lung cancer leads to alteration in lung function, thereby altering the quality of life and can also lead to death.

How Are Pneumonia and Lung Cancer Linked?

Susceptibility to pneumonia in cancer patients differs as per the cancer type, cancer stage, host response, and immune system. However, the presence of the following features in cancer patients can lead to an increased risk of contracting pneumonia.

  • Mass Lesions - The presence of lesions or tumors in the lungs can easily serve as a place to habitat any bacteria.

  • Aspiration Events - Poor ability to swallow and changes in the function of airways which can, unfortunately, occur as a complication of lung cancer treatment and can also host pneumonia.

  • Bacterial Translocation - In certain conditions, the spread of pathogens from one region to another region can occur, leading to the pneumococcal infection in the lungs.

What Causes Pneumonia in Lung Cancers?

The following are the causes of pneumonia in lung cancers:

  • Derangements in The Lung Anatomy - Changes in the anatomy's normal structure can alter function, which can easily be susceptible to infections.

  • Decreased Lung Function - Lung function can decrease due to the presence of a tumor or as a complication of lung cancer treatment, both of which can host pneumococcal infection.

  • Low Immunity - Pneumonia and even common cold can be easily caused in patients with low immunity.

What Complications Arise Due to Presence of Pneumonia in Lung Cancer Patients?

  • Empyema - Collection of infection (pus) between the lung and chest wall, causing chest pain, breathing difficulty, fever, and chills. It can be managed by proper antibiotic therapy and drainage of the infection. In certain cases, loss of lung function and death is also seen.

  • Lung Abscess - Formation of small cavities in the lung containing infective debris or fluid. It usually causes chest pain, cough, fatigue, and night sweats. Antibiotic therapy is used in the management of infection drainage. However, the outcome of the treatment depends on the patient's response to the treatment.

  • Fistula - Fistula is a collection between two surfaces. A lung fistula usually connects the lung's main stem to the space around the lung. It usually occurs after pneumonectomy or partial lung resection (removal of total or part of the lung).

Can Pneumonia Be Prevented in Cancer Patients?

Pneumonia can be prevented in cancer patients by the following:

  • Optimized sterilization protocol.

  • Preventing any oral transmission.

  • Taking care of vaccinations during lung cancer.

How Can Pneumonia in Lung Cancer Be Diagnosed?

  • Clinical Features - Though pneumonia and lung cancer cannot be clinically undifferentiated by symptoms, on keen clinical examination, the physician can arrive at a provisional diagnosis of pneumonia.

  • Chest X-ray - It is a conventional method of detecting any abnormalities in the chest cavity. Still, it is not a reliable source of diagnosis due to the evolution of newer advanced diagnostic methods.

  • Computed Tomography (CT) Scan - Nodules, infiltrates, and lobar consolidations are found in the scan. It is an advanced diagnostic tool as compared to a chest X-ray.

  • Positron Emission Tomography (PET) Scan - PET FDG (PET 18 fluorodeoxyglucose) can predict the presence of pneumonia in cancer patients.

  • Diagnostic Bronchoscopy - In patients requiring sputum for the examination that cannot be obtained, bronchoalveolar lavage with bronchoscopy is used to produce the content for examination.

  • Trans-Bronchial Biopsy - It is a process in which the lung tissue is obtained for examination of various lung diseases.

  • Serial Dilution Culture - As pneumonia is a bacterial infection, it becomes necessary to detect the presence of bacteria through serial dilution culture.

  • Urine Antigen Testing - Changes in urine antigen levels of higher C-reactive proteins can be correlated with the patient's condition.

  • Biomarkers - Biomarkers are used to detect pneumonia in patients whose immunity is compromised.

  • Endo-Bronchial Ultrasound - It is a diagnostic method used to identify the lung's tumor or mass, followed by a transbronchial biopsy.

What Are the Treatment Strategies for Pneumonia Associated Lung Cancer?

  • Antibiotic Therapy - It is started simultaneously with the diagnostic tests as there is a risk of secondary complications, including death in patients with less immunity. The antibiotics are stopped during the bronchoscopic evaluation until the completion of the process to get proper values of the diagnostic procedure.

  • AntiMicrobial Therapy - Antimicrobial, including drugs acting against a wide range of pathogens, are used to treat hospital-acquired pneumonia, ventilator-associated pneumonia, or healthcare-associated pneumonia.

  • Granulocytopenia Correction - Filgrastim, Lenograstim, and Pegfilgrastim are commercially available drugs used to correct granulocytopenia.

  • Donar Granulocytes Infusion - It is an adjunct therapy aiming to produce positive results in cancer patients.

  • Interleukin 12 - The administration of interleukin 12 has also been proposed to reduce lung infections such as pneumonia.


Pneumonia and lung cancer together can cause challenging complications in cancer patients. Clinical treatment includes standard antibacterial therapy as well as proper diagnosis. A positive outcome of the treatment is obtained by recognizing the condition early, considering the patient's clinical situation, and initiating antibiotic therapy when required. Improving the patient's clinical situation by improving the patient's immunity includes host-directed therapies, which are being studied and can replace traditional treatment methods, helping the patient to recover better. Early detection of symptoms, proper diagnosis, and consulting a physician at the earliest can avoid many complications.

Frequently Asked Questions


Can an X-ray Differentiate Between Pneumonia and Cancer?

Yes, an X-ray can help differentiate between pneumonia and cancer. Pneumonia appears as a cloudy or patchy opacity in the lungs due to infection, while cancer typically shows irregular masses or nodules. The X-ray findings, clinical symptoms, and other tests aid in accurate diagnosis and appropriate treatment planning for the patient.


How to Distinguish Between Pneumonia and Lung Cancer?

Distinguishing between pneumonia and lung cancer involves several factors. Carefully evaluating clinical symptoms, medical history, and imaging studies such as X-rays or CT scans is essential. Pneumonia is often linked to infection and may present with fever, cough, and sputum production, while lung cancer may cause symptoms like persistent cough, weight loss, and shortness of breath. Biopsy confirms the diagnosis and determines each condition's appropriate course of action.


Is It Possible for Pneumonia to Be Misdiagnosed as Lung Cancer?

Yes, pneumonia can be misdiagnosed as lung cancer and vice versa. Both conditions share similar symptoms, such as cough, chest pain, and difficulty breathing, making it challenging to differentiate based solely on clinical presentation. A thorough evaluation with imaging tests, like X-rays, CT scans, and sometimes biopsy, is necessary to distinguish between the two conditions and ensure appropriate treatment accurately.


What Are the Visual Characteristics of Lung Cancer on an X-ray?

The visual characteristics of lung cancer on an X-ray typically include irregular, abnormal masses or nodules in the lungs. These may appear as dense, opaque areas on the X-ray image. Additionally, lung cancer can cause areas of lung collapse or fluid accumulation. However, further imaging tests and diagnostic procedures, such as CT scans or biopsies, are often necessary to confirm lung cancer and determine its stage and extent.


What Happens When Someone With Lung Cancer Develops Pneumonia?

When someone with lung cancer develops pneumonia, it can lead to complications and worsen their overall health. Pneumonia in individuals with lung cancer can cause additional respiratory distress, increased susceptibility to infections, and potential delays in cancer treatment. Combining both conditions may require specialized medical attention and management to address the complexities of simultaneously treating lung cancer and pneumonia. Prompt and appropriate care is crucial to optimize patient outcomes and quality of life.


What Are the Known Causes of Lung Cancer and Other Respiratory Diseases?

There are several recognized reasons for lung cancer and other respiratory illnesses. The main reason for lung cancer is smoking, including both active and passive inhalation of tobacco smoke. Lung cancer risk is increased by exposure to carcinogens such as radon, asbestos, and certain air pollutants. Smoking and exposure to contaminants in the environment cause other respiratory illnesses, like chronic obstructive pulmonary disease (COPD). Family history, occupational exposures, and genetic factors may also influence these diseases.


What Is Another Term for Lung Cancer?

Lung cancer is also known as pulmonary carcinoma. It is a malignant tumor that originates in the lung tissues. There are two main types: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). The term pulmonary carcinoma is often used in medical contexts to specifically refer to lung cancer, highlighting its origin in the lung tissue. Early detection and timely treatment are critical for better outcomes in individuals diagnosed with pulmonary carcinoma.


What Are the Key Points for Distinguishing Between Pneumonia and Lung Cancer?

The patient's medical history, risk factors, and current symptoms are crucial for deciding between pneumonia and lung cancer. Fever, a cough that produces mucus, and chest discomfort are common symptoms of pneumonia, frequently accompanied by infection. On the other hand, lung cancer signs might be a chronic cough, an unexplained loss of weight, or trouble breathing. Imaging tests, including X-rays, CT scans, and further diagnostic examinations, are crucial for precise classification and effective therapy of various disorders. To improve patient outcomes, early and correct diagnosis is crucial.


Which Diagnostic Test Is Useful for Identifying Lung Conditions like Pneumonia, Lung Cancer, and COPD?

A chest X-ray is a useful diagnostic test for identifying lung conditions like pneumonia, lung cancer, and COPD. It provides initial insights into lung abnormalities and helps physicians determine the presence of infections, tumors, or structural lung changes. However, additional tests such as CT scans, bronchoscopy, or lung biopsies may be necessary for a more detailed evaluation and precise diagnosis. The combination of various diagnostic tools enables healthcare professionals to make well-informed decisions regarding treatment options and management strategies for patients with lung-related issues.


How Is Lung Cancer Diagnosed?

Lung cancer is typically diagnosed through a series of diagnostic procedures. It starts with imaging tests like chest X-rays or CT scans, which reveal lung abnormalities. Following this, a biopsy is often performed. This helps to confirm the presence of cancer cells and determine the type and stage of lung cancer. Early detection and diagnosis are crucial in improving treatment outcomes and survival rates for individuals with lung cancer.


Can a CT Scan Detect Pneumonia or Lung Cancer?

Yes, a CT scan can detect both pneumonia and lung cancer. CT scans provide more detailed and cross-sectional images of the lungs than conventional X-rays, making them highly effective in identifying abnormalities, such as infections or cancerous growths. Pneumonia may appear as areas of inflammation and consolidation, while lung cancer can manifest as irregular masses or nodules on the CT scan. CT scans allow for a more accurate and comprehensive evaluation of lung conditions, aiding in early detection and appropriate management.


What Are the Typical Tests Conducted for Lung Diseases?

Various tests are conducted to assess lung diseases. Some common diagnostic methods include chest X-rays, CT scans, pulmonary function tests (PFTs), bronchoscopy, and sputum analysis. These tests help evaluate lung function, detect abnormalities, and diagnose conditions such as pneumonia, lung cancer, COPD, etc. The choice of tests depends on the patient's specific symptoms and medical history, enabling healthcare professionals to provide targeted and effective treatment plans for lung-related issues.


Can a Stage 4 Cancer Patient Survive Pneumonia?

The survival of a Stage 4 cancer patient with pneumonia depends on various factors, including the patient's overall health, the extent of cancer spread, and the severity of pneumonia. Stage 4 cancer indicates that the cancer has metastasized to other parts of the body, making treatment challenging. Pneumonia can further complicate the situation, especially if the immune system is weakened due to cancer treatment. Close medical monitoring, prompt and appropriate care for both conditions, and supportive therapies are essential to improve the patient's chances of survival and quality of life.


Can Lung Cancer Manifest as Pneumonia?

Yes, lung cancer can present as pneumonia, particularly in some cases of bronchoalveolar carcinoma (a subtype of lung cancer). This type of lung cancer can appear as pneumonia-like opacities on imaging studies, such as chest X-rays or CT scans. It is crucial for doctors to carefully evaluate any persistent or atypical pneumonia cases, especially in individuals with risk factors for lung cancer, to rule out malignancy and ensure timely and appropriate management. Biopsy or further tests may be necessary to confirm the diagnosis and provide appropriate treatment for the patient.


What Is the Relationship Between Pneumonia and Cancer Treatment in Patients With Cancer?

Pneumonia in cancer treatment refers to developing lung infection during or after cancer therapies, such as chemotherapy or radiation. Cancer treatments weaken the immune system, making patients more susceptible to infections like pneumonia. It is a concerning complication that can delay or alter cancer treatment plans, affecting the overall health and outcome of individuals with cancer. Prompt identification, aggressive management, and supportive care are crucial to minimize the impact of pneumonia on cancer treatment and enhance the patient's chances of successful recovery.
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Dr. Rajesh Gulati
Dr. Rajesh Gulati

Family Physician


pneumonia in lung cancer
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