Oncology & Hematology Coding Alert

Learn the right way to code metastatic cancers.

If you’re new to oncology coding, the ICD-10-CM Table of Neoplasms can be confusing to use at first. And if you’re a seasoned pro, there’s a chance you may not be using it correctly.

So, what is the best way to use the table to ensure proper coding? In her presentation, “Neoplasm Table: Six Columns of Confusion,” Jill Young, CEMC, CPC, CEDC, CIMC, of Young Medical Consulting LLC in East Lansing, Michigan, laid out these four useful pointers that you can use the next time you try to locate a neoplasm in the table.

Tip 1: Use the Alphabetic Index First

As tempting as it may be for you to go straight to the neoplasm table to find the code that best describes the patient’s condition, the first step to correct neoplasm coding is to “always check the Alphabetical Index first,” says Lisa Selman-Holman, JD, BSN, RN, HCS-D, COS-C, HCS-O, of Selman-Holman & Associates, LLC, in Denton, Texas.

ICD-10-CM guidelines support this method of locating the correct code. Specifically, “the neoplasm table in the Alphabetic Index should be referenced first. However, if the histological term is documented, that term should be referenced first, rather than going immediately to the Neoplasm Table, in order to determine which column in the Neoplasm Table is appropriate,” according to the general ICD-10-CM guidelines accompanying Chapter 2.

Why? Simply, not all neoplasms appear in the neoplasm table. Looking for Ewing’s sarcoma? It isn’t there. But a visit to the Alphabetic Index directs you to Neoplasm, bone, malignant. This, in turn, tells you the condition should be coded to the specific bone affected. So, a pediatric patient suffering from Ewing’s sarcoma in the pelvis would be reported with C41.4 (Malignant neoplasm of pelvic bones, sacrum and coccyx).

But remember: As the instructions for using the Table of Neoplasms state, “guidance in the ICD-10-CM Index can be overridden if one of the descriptors mentioned above [malignant, benign, in situ, of uncertain behavior, or of unspecified behavior] is present; e.g., malignant adenoma of colon is coded to C18.9 [Malignant neoplasm of colon, unspecified] and not to D12.6 [Benign neoplasm of colon, unspecified] as the adjective ‘malignant’ overrides the Index entry ‘Adenoma—see also Neoplasm, benign, by site.’”

Tip 2: Don’t Ignore the Tabular List

Sometimes, even the Alphabetic Index won’t give you all the information you need for precise coding. Therefore, you must always go to the Tabular List to verify you have selected the correct code.

As an example, consider how you would code a primary malignant neoplasm of a bone in a patient’s right toe. If you look for the term “toe” in the table, it directs you to C76.5- (Malignant neoplasm of lower limb), but that is not the most specific code available to you. Additionally, the Alphabetic Index won’t help you, as it simply directs you to use the neoplasm table.

But if you know the Tabular List well, or if you review the list of blocks located at the beginning of each chapter in the Tabular List, you will know that malignant bone cancers are coded to C40.- (Malignant neoplasm of bone and articular cartilage of limbs), giving you C40.31 (Malignant neoplasm of short bones of right lower limb) as the most accurate code choice for this example. The neoplasm table confirms a more specific code if you look to the entry for Neoplasm, bone, toe, as opposed to Neoplasm, toe, but not knowing that there are separate codes for bone cancer can lead you to misread the table.

And remember: The Tabular List contains additional instructional information that goes beyond that contained in the neoplasm table and Alphabetic Index, including Not elsewhere classified (NEC), Not otherwise specified (NOS), Excludes, and Code first/Use additional code guidelines. While it may feel like a fire drill at times, you should always follow through the whole coding process and verify the code choice in the Tabular List to avoid making hasty coding mistakes.

Tip 3: Understand Uncertain/Unspecified

The columns for uncertain behavior and unspecified behavior in the neoplasm table can also be subject to misunderstanding, Young cautions. The two are not the same and are not interchangeable.

Unspecified behavior codes should be used “when the information in the medical record is insufficient to assign a more specific code” per ICD-10-CM guideline I.A.9.b. You should assign a code from this column when your oncologist is certain that a patient has a cancer but cannot assign a more specific code for that cancer. So, you would code a patient with a confirmed diagnosis of cervical cancer with unspecified code C53.9 (Malignant neoplasm of cervix uteri, unspecified) if there is no documentation that the cancer is in the endocervix or exocervix, for example, as those locations have their own, more specific codes.

Uncertain behavior codes should be used in circumstances where a pathologist’s report specifically states that the histologic behavior of the cancer cannot be determined or predicted based on current testing. In other words, you will only assign a code such as D49.59 (Neoplasm of unspecified behavior of other genitourinary organ) if the pathology report states the specimen’s behavior is uncertain. This would be because the pathologist cannot provide “histologic confirmation whether the neoplasm is malignant or benign,” per the note for the D37-D48 codes.

Tip 4: Remember Primary and Secondary Can Mean Different Things

The table’s designations of malignant neoplasms as either primary (where the neoplasm originated), secondary (where it has spread to, or metastasized), or in situ (a neoplasm that does not spread past the site of origin) are important for many reasons, but from a coding perspective, sometimes a secondary neoplasm can be coded as a primary diagnosis, and vice versa.

Why? “If the treatment is directed at a malignancy, then that malignancy would be regarded as the principal diagnosis. In other words, if the treatment is directed to a secondary malignancy, that is principal diagnosis in this specific encounter,” said Young.

Example: A patient has colon cancer that has spread to the liver and is reporting to your oncologist for treatment of the cancer that has now metastasized to the liver. In this example, the patient still has colon cancer, but the primary diagnosis code you would use for the encounter is the metastatic, or secondary, liver cancer, not the colon cancer.

So, you would not code the colon cancer (C18.9, Malignant neoplasm of colon, unspecified) first, as that is not what is being treated at this encounter. And neither would you code C22.8 (Malignant neoplasm of liver, primary, unspecified as to type) because the liver cancer being treated is not the primary cancer. You also should not report C78.5 (Secondary malignant neoplasm of large intestine and rectum) because the liver cancer was metastatic to the colon. Instead, as the treatment is directed to the liver, you will use C78.7 (Secondary malignant neoplasm of liver and intrahepatic bile duct) as the principal diagnosis for this encounter.

A note of caution: For metastatic cancers, always closely scrutinize your provider’s documentation. “If your provider notes the cancer is metastatic to, that means the cancer is secondary. If the note reads metastatic from, that means the cancer is primary,” Young noted (emphasis added).