Metastatic Lung Cancer ICD 10 Code

Refresher: What are ICD-10 codes?

ICD-10 is the tenth version of the International Classification of Diseases, a standardized coding system consisting of alphanumeric codes that classify diseases, symptoms, complaints, procedures, and abnormal findings.[¹]

These codes form a common language for the healthcare industry and improve the quality of data for tracking, reporting, and recording medical conditions, which in turn supports a variety of areas such as medical billing, reimbursements, service planning, and medical research.[²][³]

The ICD was first developed in the early 19th century and was initially used to improve record-keeping for mortalities, and over the years, it was updated multiple times to include more codes. Since 1948, it has been under the administration of the World Health Organization (WHO). WHO continues to update the ICD and has periodically updated every decade with past revisions made in 1955, 1965, 1975, and 1990. [⁴]

Many countries have adopted ICD-10 and modified it to suit their healthcare system. In the US, these modified revisions are called ICD-10-CM (clinical modification), which is used for disease diagnosis, and ICD-10-PCS (procedure coding system), which is used for inpatient medical procedures. For active malignant neoplasms, ICD-10 codes C00 – D49 are used as given below:

• C00 – C97 is for malignant neoplasms
• D00 – D09 is for in situ neoplasms
• D10 – D36 is for benign neoplasms
• D37 – D49 is for neoplasms of unknown or uncertain behavior

However, this range is only for primary malignant neoplasms. Different codes are used for secondary or metastasized malignant neoplasms.[¹]

Furthermore, while the terms cancer and neoplasm are often used interchangeably, they are not the same because a neoplasm can be cancerous or noncancerous.[⁵]

What is the ICD 10 code for metastatic lung cancer?

Medically, lung cancers with growths still within their site of origin are considered primary and are coded under C34, which defines malignant neoplasm of the bronchus and lung. [⁶]

However, metastatic lung cancer is a cancerous growth that has spread from where it started in the lungs to other parts of the lung and body.Therefore, it falls under ICD 10 code C78.0, secondary malignant neoplasm of the lung[⁷][⁸]

Further specifications are detailed below.

Primary lung cancer ICD 10 code: C34

Primary lung cancer ICD 10 code C34 lookup

The table below lists the ICD-10 lung cancer codes for primary lung cancers classified under C34. [⁶]

C34: Malignant neoplasm of the lung [6]

Types of lung cancer included under C34

The ICD 10 code C34 does not specify any type of lung cancer and can be used for various primary lung cancers, including, but not limited to:[⁹]

• Pulmonary adenocarcinoma
• Small cell lung cancer
• Non-small cell lung cancer
• Mixed small cell lung cancers
• Squamous cell lung carcinoma

In other words, the pulmonary adenocarcinoma ICD 10, non-small cell lung cancer ICD 10, and small cell lung cancer ICD 10 codes can all be C34.32 if they are diagnosed as primary malignancies in the lower lobe of the left bronchus or lung.

However, once any of these spread, they are no longer considered primary and are given the code for secondary and metastatic lung cancer. For example, if a patient’s previously diagnosed stage II pulmonary adenocarcinoma advances and spreads to other parts of the body, it is now metastatic, and the ICD 10 code will change from C34 to C78.

Lung cancers excluded from ICD-10 C34

Lung cancers excluded from ICD-10 C34 are Kaposi’s sarcoma of the lung and malignant carcinoid tumor of the bronchus and lung. These malignancies are given ICD-10 codes C46.5 and C7A.090, respectively.[⁶]

Secondary and metastatic lung cancer ICD 10 code: C78

Secondary or metastatic lung cancer ICD 10 code C78 lookup

Metastatic lung cancer shares the same ICD-10 code as secondary lung cancers, C78, i.e., secondary malignant neoplasm of the lungs. This code is further divided as given below: [⁸]

• C78.00 for secondary malignant neoplasms of the unspecified lung
• C78.01 for secondary malignant neoplasms of the right lung
• C78.02 for secondary malignant neoplasms of the left lung

Conclusion

The ICD-10 code for metastatic lung cancer falls under C78.0 regardless of the subtype. Therefore various cases of different types of metastatic lung cancers can be given the same ICD-10 code.

Furthermore, the C78 ICD 10 codes do not define the exact site of origin as cancer has spread to other parts. Given this, it is important to understand a patient’s case history, pathophysiology, treatments, complications, and pre-existing and co-existing conditions to accurately record and report their specific case of metastatic lung cancer.