Revised Guidelines for ICD-10 Oncology Coding

Revised Guidelines for ICD-10 Oncology Coding

2020 Coding Update

The Centers for Medicare & Medicaid Services (CMS) and the American Medical Association (AMA) have finalized the coding updates for calendar year (CY) 2022. Overall, there are no significant coding changes impacting oncology, but it is important to be prepared and ensure that your coding team is well aware of these changes. Finalized coding update outlines coding changes specific to the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM), Current Procedural Terminology (CPT®), and Healthcare Common Procedure Coding System (HCPCS). In this article, we will focus only on revised guidelines for ICD-10 oncology coding.

Revised Guidelines for ICD-10 Oncology Coding

Many of the guidelines updated for 2022 focus on the need to code the diagnosis to the highest level of specificity. Language was added in several sections of the ICD-10-CM official guidelines to press this point. New in 2022, the guidelines state the following:

  • Highest level of specificity: Code to the highest level of specificity when supported by the medical record documentation.
  • When laterality is not documented by the patient’s provider, code assignment for the affected side may be based on medical record documentation from other clinicians. If there is conflicting medical record documentation regarding the affected side, the patient’s attending provider should be queried for clarification. Codes for “unspecified” side should rarely be used, such as when the documentation in the record is insufficient to determine the affected side and it is not possible to obtain clarification.

There may be instances in which signs and symptoms need to be coded based on the reason for the encounter. When there is no specificity supported in the medical record, coders and practitioners will need to discuss documentation. A joint effort between the healthcare provider and the coder is essential to achieve complete and accurate documentation, code assignment, and reporting of diagnoses and procedures. The importance of consistent, complete documentation in the medical record cannot be overemphasized. Without such documentation, accurate coding cannot be achieved. The entire record should be reviewed to determine the specific reason for the encounter and the conditions treated.

The diagnosis code is not the only piece of information provided under the ICD-10-CM system. There are factors influencing health status that provide more information about the patient. These factors can be used in registries to provide additional context to the patients seen for healthcare services. For example, “History of” codes, which begin with the letter “Z,” contain personal and family history. When practitioners document statements in the medical record related to the “History of,” they should be coded. Language was updated to reinforce the sequence of codes listed on the claim form. The reason for the encounter—for example, screening or counseling—should be sequenced first and the appropriate personal and/or family history code(s) should be assigned as an additional diagnosis(es).

Revised ICD-10 Oncology Codes

New for 2022, codes to denote malignancy to bilateral ovaries are available; previously the codes were only specific to the right or left side:

  • C56.3: Malignant neoplasm of bilateral ovaries
  • C79.63: Secondary malignant neoplasm of bilateral ovaries.


There are also new codes related to anaplastic large cell lymphoma for breast cancer. Added codes and guidance include the following:

  • C84.79A: Anaplastic large cell lymphoma, ALK-negative, breast

For breast implant associated with anaplastic large cell lymphoma (BIA-ALCL), use an additional code to identify: breast implant status (Z98.82) and personal history of breast implant removal (Z98.86). Do not assign a complication code from chapter 19.

Differences between ICD-O and ICD-10

There are basic differences between the structure of ICD-O and that of ICD. In Chapter II (Neoplasms) of ICD, the topography code describes the behavior of the neoplasm (malignant, benign, in situ, or uncertain whether malignant or benign) by assigning it to a specific range of codes identifying each of these types of behavior. As a result, in ICD-10, five different categories of four characters each are needed to describe all lung neoplasms. Very few histological types are identified in ICD. For example, there is no way in ICD to distinguish between an adenocarcinoma of the lung and a squamous cell carcinoma of the lung: both would be coded to C34.9.

The ICD-10 alphabetic index (Vol. 3) contains, under the term “neoplasm”, a table of five columns with the following headings: Malignant, Secondary or Metastatic, In situ, Benign, Uncertain and Unknown Behavior. Appropriate ICD-10 categories for each site of the body are then listed in alphabetic order. ICD-O uses only one set of four characters for topography (based on the malignant neoplasm section of ICD-10); the topography code (C34.9, lung) remains the same for all neoplasms of that site.

Legion Health Care Solutions is a leading medical billing company that can assist you in revenue cycle functions for your practice. We hope that above mentioned revised guidelines for ICD-10 oncology coding would help in coding oncology services more accurately. In case of any assistance needed in billing and coding for your oncology practice, contact us at 727-475-1834 or email us at


Reference: International Classification of Diseases for Oncology (ICD-O)- First Edition

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