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Colon Cancer ICD 10 Code
Refresher: What are ICD-10 codes?
The International Classification of Diseases was developed in the 1850s as a system to standardize medical records and data using a single coding system. The ICD-10 (10th edition) began in 1983, with the World Health Organization managing the official list of codes. Countries that have adopted the ICD-10 have modified them based on their specific healthcare system requirements.
The US version of the ICD-10 was constructed in collaboration with the National Center for Health Statistics (NCHS) and the Centers for Medicare & Medicaid Services (CMS). The code consists of two sets of medical codes, the ICD-10-PCS and the ICD-10-CM. The former is mainly used for coding procedures used in inpatient settings, while the latter is used for disease diagnosis.
The coding systems are used for statistical purposes as well as for processing medical claims. "ICD" denotes the International Classification of Diseases, while the numerical figure "10" denotes the edition (the classification is currently in its 10th edition). ICD-10 codes are different for primary tumors (malignant neoplasms) and secondary or metastasized tumors (secondary malignant neoplasms).[1]
Currently, there are over 70,000 ICD-10-PCS codes and around 68,000 ICD-10-CM codes used for defining malignant neoplasms.[2]
What is the ICD 10 Code for colon cancer?
The body is made of tissue that contains cells. Cancer is the name given to a condition where these cells start multiplying uncontrollably, resulting in a condition that is known as a malignant neoplasm, or the abnormal growth of tissue. What makes this uncontrollable multiplying of cells dangerous in the body is that the malignant cells tend to destroy the healthy cells and tissue as they spread to other parts of the body. Colon cancer is when the cells that are present in the large intestine or colon have uncontrollably multiplied.
The colon runs as an upside-down U, with the first portion located in the lower right corner of the abdomen. This continues upwards and runs across the right to left of the abdomen before descending. This is followed by an S-shape region of the intestine that's at the bottom left of the abdomen, which goes all the way to the rectum, which is the last section of the colon.
Colorectal cancer affects men and women of all racial and ethnic groups and is most often found in people aged 50 years or older it is the third most common cancer among men and women in the United States. The good news is that there are ways to detect colon cancer at an early stage and treat the condition before it metastasizes.
The US Preventive Services Task Force has recommended that individuals begin colorectal cancer screening tests once they reach the age of 50 and carry out these tests until they reach 75 years of age. The screening methods that the USPSTF has recommended include a colonoscopy, a sigmoidoscopy, and a fecal occult blood test.
The typical growth which originates within the colon is known as colon cancer, while any growth which originates within the rectum is classified as rectal cancer. Colorectal cancer is often used as an umbrella term to describe both types of cancers mainly because they share so much in common. This is the reason why multiple ICD-10 codes fall under this particular type of cancer.
Primary colon cancer ICD 10 Code: C18
The ICD-10 code C18.9 is used to categorize malignant neoplasm of the colon. C18 is an ICD-10-CM code that is billable and is used to indicate the diagnosis of colon cancer for reimbursement purposes. This code became effective in October 2022.
Primary colon cancer ICD Code C18 lookup
Below is a table of the ICD 10 Colon Cancer codes for primary Colon cancers, which are classified under C18-C20, “malignant neoplasm of Colon”.[3], [4], [5]. Adenocarcinoma is considered to be one of the most common types of colorectal cancer and makes up 95% of cases involving colorectal cancer. Adenocarcinomas mainly develop within the cells of the lining inside the large intestine.[6]
C18-20: Malignant neoplasm of the Colon
Types of colon cancer coded under C18
The most common types of colon cancer that are coded under C18 include;
- Signet ring cell adenocarcinoma
- Primary colorectal lymphomas
- Mucinous adenocarcinoma
- Gastrointestinal stromal tumors
- Colorectal leiomyosarcomas
- Adenocarcinoma
Colon cancers excluded from ICD-10 C18-20
Malignant carcinoid tumors of both the colon and the rectum have been excluded from the coding system. The ICD codes do not cover malignant carcinoid tumors of the colon or rectum mainly because this particular type of cancerous growth begins in the neuroendocrine cells that are found within the digestive tract. That being said, the primary malignant neuroendocrine cancer, such as the rectum and colon carcinoid tumors, have been labeled C7A.2 under the ICD 10 coding system.
Secondary and metastatic colon cancer ICD 10 code: C18-21.8 and C78.5-6, D37.4-5
The secondary and metastatic colon cancer under ICD 10 codes: C18-21.8 and C78.5-6, D37.4-5, include: Malignant neoplasm of hepatic flexure, Malignant neoplasm of transverse colon, Malignant neoplasm of the splenic flexure, Malignant neoplasm of descending colon, Malignant neoplasm of sigmoid colon, Malignant neoplasm of overlapping sites of the colon, Malignant neoplasm of colon, unspecified, Malignant neoplasm of the rectosigmoid junction, Malignant neoplasm of rectum, Malignant neoplasm of overlapping sites of the rectum, anus and anal canal, Secondary malignant neoplasm of large intestine and rectum, Secondary malignant neoplasm of retroperitoneum and peritoneum, Neoplasm of uncertain behavior of colon, and Neoplasm of uncertain behavior of rectum.[7]
Secondary or Metastatic Colon Cancer ICD-10 Code: C78.5 Lookup
The ICD 10 codes for colorectal cancer, which originate within the rectum or the colon and have metastasized to other parts of the body, have been coded under 78.5. These also include the following types of secondary malignant neoplasms;
- Secondary malignant neoplasm of the rectum
- Secondary malignant neoplasm of the rectosigmoid junction
- Secondary malignant neoplasm of the large intestine
Conclusion
What we learn here from taking a look at the ICD coding system for colon cancer is that the coding that denotes the various types of colorectal cancers depends on multiple factors, such as the specific location of the malignancy and whether there is a primary and secondary malignant neoplasm. The primary colorectal cancer, which is found in the colon, has been coded ICD 10 C18, while the primary colorectal cancer found in the rectum and the rectosigmoid junction coded as ICD 10 C20 and ICD 10 C19, respectively.