Small cell lung cancer (SCLC) is a fast-growing cancer that develops in cells within the lung. A range of medical tests and procedures are available to help doctors diagnose SCLC and create an appropriate treatment plan.

Lung cancer is a complex disease comprising various subtypes. A person who receives a diagnosis of SCLC may want to get a second opinion to confirm the diagnosis and offer reassurance about their proposed treatment plan.

A second opinion can also help a person gain access to clinical trials that may not be available elsewhere.

This article explains the ways doctors diagnose SCLC.

A healthcare professional explaining the x-ray results to a person who may have small cell lung cancer.Share on Pinterest
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According to the American Cancer Society, doctors may order one or more of the following imaging tests to diagnose or stage lung cancers.

Cancer staging is an important part of the diagnostic process for SCLC. It helps determine whether and to what extent the cancer has spread.

Chest X-ray

A chest X-ray is one of the first tests doctors order to check for abnormalities in the lungs. Areas that appear abnormal will prompt doctors to order further tests.

CT scan

A CT scan uses X-rays to take a series of cross-sectional images of the body. It then combines these images to produce a more detailed image.

A CT scan can help doctors detect lung tumors and determine their location, size, and shape. A CT scan can also help doctors detect enlarged lymph nodes and tumors in other parts of the body, either of which may indicate that the cancer has spread.

A CT scan is more effective at finding lung tumors than a routine chest X-ray.

MRI scan

MRI uses strong magnets and radio waves to produce detailed images of the body’s soft tissues. Doctors often use MRIs to look for signs that a cancer has spread to other organs or tissues in the body.

PET/CT scan

A PET/CT scan involves injecting a slightly radioactive sugar into the blood and using CT scans to assess levels of radioactivity in the body.

Because cancer cells tend to take up more sugar than normal cells, areas of high radioactivity on a CT scan may indicate the presence of cancer cells.

Doctors typically use PET/CT scans for cancer staging.

Doctors may use a needle biopsy to collect tissue or cells from a suspicious lung mass. After collecting these samples, they analyze them under a microscope to look for cancer cells.

There are three main types of needle biopsy for SCLC. These are outlined next.

Fine needle aspiration (FNA) biopsy

FNA biopsy involves inserting a very thin, hollow needle into the mass to withdraw cells or small fragments of tissue.

This type of needle biopsy can help doctors detect cancer in very small masses or in the lymph nodes surrounding the lungs.

Core biopsy

A core biopsy involves using a larger needle to remove one or more small cores of tissue from a suspicious mass. Surgeons may perform this type of biopsy during lung surgery.

Thoracentesis

Pleural effusion is the medical term for excess fluid in the pleural space, which is the fluid-filled space around the lungs. There are many potential causes of pleural effusion.

Thoracentesis is a procedure that doctors may use to determine whether pleural effusion is due to lung cancer spreading to the lining of the lungs or another condition.

This procedure involves inserting a hollow needle between the ribs to help drain excess fluid from the pleural space.

An endoscopy is a procedure that allows doctors to see inside the body using a scope. The scope is a thin, flexible tube with a light and camera at one end.

Scopes also contain tiny instruments that allow doctors to take samples from any abnormal-looking tissues. Doctors can then analyze the samples under a microscope to check for cancer cells.

There are many types of endoscopies, including:

  • Bronchoscopy: Bronchoscopy involves using a type of scope called a bronchoscope to look inside the lungs. A doctor inserts the bronchoscope through the mouth or nostril, down the windpipe, and into the airways of the lungs.
  • Thoracoscopy: Thoracoscopy allows doctors to investigate the pleural space, which is the space between the lungs and the chest wall. The procedure involves inserting a type of scope called a thoracoscope through a small cut beneath the shoulder blade and between the ribs.
  • Mediastinoscopy: Mediastinoscopy is a procedure that allows doctors to investigate the mediastinum, which is the area between the two lungs. It involves inserting a device called a mediastinoscope behind the breastbone and in front of the windpipe. Small instruments inside the mediastinoscope allow doctors to take tissue samples from the lymph nodes along the windpipe and major bronchial tube areas.

Disease specialists called pathologists analyze biopsy samples to determine whether a person has lung cancer and to establish the type.

Laboratory tests can also determine whether the cancer originated in the lungs or spread from elsewhere in the body. This is important, as treatments differ depending on where the cancer originated.

Molecular testing is a type of laboratory test that involves checking for specific gene changes in cancer cells. Identifying these changes can help doctors determine whether a cancer may be responsive to targeted drug therapies.

Once the pathologist has analyzed the samples, they write the results in a pathology report. This report is typically available within 1 week.

As the American Lung Association explains, lung cancer staging helps doctors determine the following:

  • the location of the lung cancer cells
  • the size of the lung cancer nodules
  • whether and to what extent the cancer has spread

Lung cancer staging can also help doctors establish the most appropriate treatment options for a person’s lung cancer. Staging may also offer insights on a person’s outlook.

Staging systems

According to the American Cancer Society, doctors use the American Joint Committee on Cancer (AJCC) TNM staging system to describe the growth and spread of SCLC. The TNM acronym stands for:

  • T (tumor): the size of the tumor and whether it has grown into nearby structures or organs
  • N (nodes): whether the cancer has spread to nearby lymph nodes
  • M (metastases): whether the cancer has spread, or “metastasized,” to distant organs or tissues

For treatment purposes, doctors typically use a staging system that groups SCLC into one of the following two stages:

  • Limited stage: The cancer is confined to one side of the chest. The affected area is small enough that the person can receive radiation therapy in that one area. Around 33% of SCLCs are limited stage at the time of diagnosis.
  • Extensive stage: The cancer has spread extensively throughout the lung or has spread outside of the lung where it originated. This may include the opposite lung or other organs and tissues in the body. Around 66% of SCLCs are extensive stage at the time of diagnosis.

People who have received a diagnosis of SCLC may benefit from seeking a second opinion about their diagnosis. A second opinion can help:

  • confirm the diagnosis and provide reassurance about the proposed treatment plan
  • provide insights into other potential treatment options that may be more effective or have fewer side effects
  • open opportunities for participation in clinical trials that may not be available at other medical institutions

For individuals who want to seek a second opinion, the Lung Cancer Foundation of America advises finding a healthcare professional who specializes in lung cancer, such as a:

  • thoracic oncologist
  • medical oncologist
  • radiation oncologist

The organization also advises bringing all relevant medical records to the initial consultation so that the doctor is better able to understand the specifics of the case and offer an informed opinion. Medical records to bring include:

  • pathology reports
  • imaging scans
  • genomic testing results, sometimes called biomarker results

The National Cancer Institute provides a cancer information service where people can ask an adviser for information and guidance on seeking a second opinion.

How quickly does SCLC progress?

Doctors sometimes use “doubling time” to describe how quickly a cancer is growing. Doubling time describes the amount of time it takes for a single cell to divide or the amount of time it takes for a tumor to double in size. Lower doubling times indicate a faster-growing cancer.

SCLC is an aggressive disease with a short doubling time and a high risk of early spread. SCLC symptoms typically develop suddenly and often persist for 8 to 12 weeks before a person visits a doctor. Despite this relatively short time frame, most SCLC cases are extensive stage at the time of diagnosis.

What are the survival rates for SCLC?

The 5-year relative survival rate denotes the percentage of people who are alive 5 years after their initial diagnosis compared with people who do not have that diagnosis.

According to the American Cancer Society, the 5-year relative survival rates for SCLC are:

  • Localized: 30%
  • Regional: 18%
  • Distant: 3%

SCLC is an aggressive form of lung cancer that tends to grow and spread rapidly. For people with SCLC, receiving an accurate diagnosis is the first step toward receiving appropriate treatment.

Doctors may use a range of diagnostic tests and procedures to diagnose and stage SCLC.

The first step is usually a chest X-ray. If this shows abnormalities within the lungs, doctors may order additional tests, such as other types of imaging scans, needle biopsies, or endoscopy. Laboratory tests of biopsy samples can confirm the diagnosis of SCLC.

Lung cancer is a complex disease. A person who receives a diagnosis of SCLC may want to seek a second opinion. A second opinion can help confirm the diagnosis and offer reassurance about a proposed treatment plan. It can also provide a person with access to clinical trials that may not be available at other medical facilities.