Anal Cancer ICD 10 Code

Refresher: What are ICD-10 codes?

The ICD-10 (International Classification of Disease) is a data standard that tracks various public health conditions, including different types of cancers. Its primary aim is to simplify clinical diagnosis and billing systems for payment and processing. Healthcare organizations in the US had been using the ICD-9-CM version since 1979, but the system had various limitations due to inaccuracy and restrictive coding structure [¹].

Furthermore, the ICD-9 system didn't allow organizations to compare US diagnostic data at the international level. The ICD-10 provides more uniformity and makes it easier to measure healthcare outcomes for patients. There are over 68,000 codes in the ICD-10-CM, compared to some 13,000 ICD-9-CM codes, with new codes being periodically added [²].

The system has a higher number of codes primarily due to its specificity. Some of the biggest advantages of ICD-10-CM include:

Having a higher level of detail that includes the severity, location, and complexity of the disease
Terminology of the diseases is now more consistent thanks to new technology
The new system adds improved concepts that previously did not exist in the ICD-9-CM

Note that the term ICD-10-CM is simply a clinical modification of the WHO’s ICD-10 for the purposes of reporting diagnoses and procedures in the US. In other words, the codes used in ICD-10 and ICD-10-CM are virtually the same. The ICD-10-PCS, however, is a different classification system used for inpatient, hospital settings in the US.

What is the ICD 10 code for Anal Cancer?

For primary anal cancer, the general ICD-10 code is C21 (malignant neoplasm of the anus). It may be known by several synonyms, including cancer anal melanoma, cancer of the anus, and malignant melanoma of the anus, among others. Note that anal cancer should not be confused with colon cancer, which forms in the large intestine.

Primary Anal Cancer ICD 10 code: C21

Primary malignant neoplasm of anus and anal canal ICD code C21 lookup:

Below is a table of the ICD 10 anal cancer codes for primary malignant neoplasm of the anus, which is classified under C21.0, “malignant neoplasm of the anus.”

C21: Malignant neoplasm of the anus and anal canal

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Data shows that most anal cancers are related to an HPV (human papillomavirus) infection [³]. In fact, 90% of all anal cases are linked to an HPV infection. HPV is a highly prevalent sexually transmitted disease that is spread from one person to another through sexual contact [⁴].

Anal cancer is relatively rare and only accounts for about 1 to 2% of all cancers of the intestines. The disease mostly affects people in the 55-64 age bracket. Anal cancer is less common in people under the age of 35. It is less common than colorectal cancer and only affects 1 in 500 people in their lifetime compared to 1 in 22 people [⁵].

With that said, the number of anal cancer cases has been growing over the years. The five-year survival rate for anal cancer is about 83% if it is caught at an early stage. If the anal cancer spreads to the surrounding tissues or organs, then the five-year survival rate will be about 67%.

Some of the most common symptoms of anal cancer include:

Rectal bleeding
Pain and itching around the anal area
Formation of small lumps around the anus
Discharge of mucus from the anus
Bowel incontinence

It is worth noting that some people with anal cancer may not have these symptoms. This is why you should talk to your doctor if you develop any of these symptoms. Diagnosing anal cancer is usually done through a rectal examination. The doctor will use their finger to feel for any lump around the anal area. This is then followed by further tests, such as a biopsy, where a small tissue sample is removed from the anus to study it under a microscope.

These tests can be used to identify the stage and type of cancer. The primary treatment for anal cancer is surgery (to remove the tumor) or a combination of chemotherapy and radiotherapy.

Types of anal cancer coded under C21

The ICD 10 code C21 does not specify the subtype of anal cancer. A C21 code can be used for primary malignant neoplasm of the anus and anal canal cancers of various types:

Cancer of the anal canal
Primary malignant neoplasm of the anal canal
Squamous cell carcinoma of the anal canal
Primary squamous cell carcinoma of the anal canal
Primary malignant neoplasm of the cloacogenic zone
Cancer cloacogenic cone
Cancer of the anal canal, rectum, or anus
Cancer of the rectum, anus, or anal canal and overlapping sites
Malignant neoplasm of anorectum
Epidermoid cancer
Overlapping malignant neoplasm of the anus, anal canal, and rectum

In other words, anal cancer ICD 10, malignant neoplasm of the anal canal ICD 10, and malignant neoplasm of clonogenic zone ICD 10 codes could all be C21 if they are determined to be primary malignant neoplasm of the anus. As a concrete example, a patient diagnosed with squamous cell carcinoma of the anal margin, with tumors found in the anal canal may be coded C21.0.

Comparing the ICD-10 with the ICD-9 reveals that the former allows for more specificity and details when diagnosing diseases. This makes it easier for medical professionals to treat the type of anal cancer depending on its origins. This also makes it easier for patients to undergo treatment if they consult different physicians.

Another goal of the ICD-10 is to simplify the storage of medical histories for patients, making it more consistent and organized. This allows physicians in different healthcare organizations to know if the malignant neoplasm is in the anal canal or the cloacogenic zone.

The ICD-10 system isn’t without its disadvantages. For one, the transition to ICD-10 from ICD-9 systems can be relatively expensive with long waiting times. During the transitory period, the organization may notice a slump in productivity until the systems are updated to ICD-10.

Healthcare providers and medical coders will also have to upgrade their certifications in line with ICD-10-CM. This would require investing considerable time and money into classes and seminars.

Switching to the ICD-10-CM billing system may take a long time for healthcare providers to adapt to. Cash-strapped healthcare organizations with a smaller budget may not be able to commit the resources needed for the update.

It also goes without saying that the high specificity of ICD-10 codes is like a double-edged sword. On the one hand, it allows healthcare professionals to accurately identify the diseases, and on the other, there is a chance that the disease could be miscoded.

The high processing requirements for the ICD-10 make it more likely for inexperienced coders to misidentify the proper code. For example, if the coder miscodes the cancer of the anal canal with the clonogenic zone, when in fact, they may have malignant neoplasm of the anal canal, the patient may have a negative experience with the treatment.

The accuracy might also expose the patient to undesirable side effects of treatments that could exacerbate their symptoms. Miscoding can also result in the denial of healthcare insurance.

Malignant neoplasm of anus cancers excluded from ICD-10 C21

The following types of cancers are excluded from ICD-10 C21:

Malignant carcinoid tumors of the colon (under C7A.02)
Malignant melanoma of the anal margin (under C43.51)
Malignant melanoma of anal skin (C43.51)
Malignant neoplasm of the colon (C18.9)
Malignant melanoma of the perianal skin (C43.51)
Other and unspecified malignant neoplasm of the anal margin (C44.500)
Other and unspecified malignant neoplasm of the anal skin (C44.500)
Other and unspecified malignant neoplasm of the perianal skin (C44.500)

It is common to confuse anal cancer with the more prevalent colorectal cancer. To clarify, anal cancer affects the short canal through which stool exits the body. Colon cancer, on the other hand, develops in the large intestine. Due to the nature of both cancers, their symptoms are very similar, making it easy to confuse them.

Conclusion

So there you have it, an in-depth look at the ICD-10 codes for anal cancer. The coding system allows medical professionals and coders to make detailed diagnoses of malignant neoplasms of the anus and anal canal. The coding system does not apply to malignant melanoma of the anal skin and the perianal skin.

Please note that the information provided so far is only meant to be used for reference purposes. If you experience any of the symptoms of anal cancer, you should visit a healthcare professional at the earliest for diagnosis. You should also direct any questions you have about ICD-10 C21 codes for anal cancer to a healthcare professional.