Common Oncology CPT Codes in Billing

Last Updated on September 18, 2025 by admin

Oncology coding is one of the most detail-driven areas in medical billing. Cancer treatment involves multiple disciplines, medical oncology, radiation oncology, surgical oncology, pathology, and more. Each step of the patient journey requires precise coding to capture services for reimbursement, compliance, and quality reporting.

According to the American Cancer Society, there are an estimated 2 million new cancer cases in the United States in 2024, with spending on cancer care projected to reach over $240 billion by 2030 (NIH Cancer Trends). With such a large financial footprint, accurate coding is critical to keeping oncology practices financially healthy and ensuring patients continue receiving uninterrupted care.

CPT codes are the language payers use to understand what services were provided. In oncology, these codes cover everything from initial consultations and chemotherapy administration to radiation treatment planning and new therapies like CAR T-cell. 

The following guide walks through the most common CPT codes in oncology billing, offering practical explanations to help coders and billers capture services accurately.

Why CPT Codes Matter in Oncology

Every oncology service needs to be linked with the correct CPT code. Incomplete or inaccurate reporting can result in delayed reimbursements, underpayments, or unnecessary rework. But more importantly, coding accuracy also supports:

• Patient trust – ensuring patients are billed correctly for complex care.
• Revenue cycle efficiency – preventing denials and reducing administrative backlogs.
• Compliance – aligning with CMS and payer-specific rules for oncology services.
• Data-driven care – coding data feeds into cancer registries, treatment audits, and outcome studies.

Oncology coding isn’t about memorizing numbers; it’s about understanding which code best represents the service delivered in a specific clinical context.

Evaluation and Management (E/M) Codes in Oncology

Oncology often starts with evaluation, discussing a diagnosis, staging the disease, and planning treatment. CPT codes for Evaluation and Management (E/M) visits are some of the most frequently reported.

• 99202–99205: New patient office visits
• 99211–99215: Established patient visits

Because oncology involves high-complexity decision-making, coders should pay attention to time spent and medical decision-making (MDM) level. For example, oncology physicians frequently spend extended time reviewing lab results, imaging studies, and coordinating multi-specialty care. Proper documentation of complexity ensures accurate coding at higher levels, which directly affects reimbursement.

Chemotherapy Administration Codes (96400–96549)

Chemotherapy coding is one of the most essential skills in oncology billing. These codes capture how chemotherapy drugs are administered, whether by intravenous infusion, push, or other routes.

• 96413: Chemotherapy, intravenous infusion, up to 1 hour, initial
• 96415: Each additional hour (after 96413)
• 96409: IV push, single or initial substance
• 96411: Each additional sequential IV push

Why it matters: Chemotherapy codes are time-based. Coders must know when an infusion starts, how long it runs, and whether additional drugs are administered sequentially or concurrently. Missing these details leads to lost revenue.

Supporting services like hydration or antiemetic administration have their own CPT codes (e.g., 96360–96361), but they cannot be billed as chemotherapy unless documented as such.

Radiation Oncology Codes

Radiation therapy uses its own category of CPT codes because it includes planning, delivery, and management. Radiation oncology coding can be complex since treatment often occurs over multiple sessions.

Common codes include:

• 77261–77263: Radiation therapy planning (simple to complex)
• 77300: Basic radiation dosimetry calculation
• 77427: Radiation treatment management, 5 treatments
• 77790: Supervision of radiation therapy, complex cases
  

One key difference in radiation oncology is global vs technical vs professional components. Coders should apply modifiers based on whether the physician only supervised or also performed the service.

Infusion and Supportive Therapy Codes

Not every oncology infusion is chemotherapy. Many patients receive supportive therapies, such as hydration, antiemetics, or growth factor injections. These use non-chemo infusion codes:

• 96365: Initial IV infusion, up to 1 hour
• 96366: Each additional hour
• 96372: Subcutaneous or intramuscular injection, single drug
  

These codes ensure that supportive care, often essential for quality of life during cancer treatment—is properly documented and reimbursed. Coders should be careful not to confuse them with chemotherapy codes.

Pathology and Laboratory Codes in Oncology

Oncology depends heavily on pathology for diagnosis. CPT codes in this area include:

• 88305: Level IV surgical pathology (commonly used for biopsies)
• 88342: Immunohistochemistry (IHC) per specimen
• 88360: Morphometric analysis, quantitative immunohistochemistry

These codes reflect the work of pathologists in identifying tumor type, staging, and molecular markers that guide targeted therapy. As oncology shifts toward personalized medicine, molecular testing codes are increasingly important.

New and Emerging Codes: CAR T-Cell Therapy

Innovations in oncology bring new codes. One example is CAR T-cell therapy, a type of immunotherapy where a patient’s T-cells are modified and reintroduced to fight cancer.

• 38225: Bone marrow biopsy and aspiration
• 38230–38232: Cell harvesting and preparation
• 38999: Unlisted hematology procedure (used in certain CAR T contexts, until newer codes are added)

CAR T-cell therapy is expensive, costing upwards of $373,000 per patient (NCI CAR T-cell therapy data). Coders need to be up to date on how payers are reimbursing these services since new codes continue to evolve.

Common Oncology Coding Challenges

Even with clear guidelines, oncology billing presents challenges:

• Drug vs administration coding – Both the drug (HCPCS J-codes) and the administration (CPT codes) must be captured.
• Concurrent vs sequential infusions – Misclassifying can change reimbursement significantly.
• Modifiers in radiation therapy – Incorrect use of -26 or -TC leads to payment delays.
• Emerging therapies – Coders must keep up with new oncology codes updated annually by CPT and CMS.

Best Practices for Oncology Coding

To strengthen oncology billing accuracy, consider these coding best practices:

• Stay current – CPT codes are updated annually; oncology has frequent changes.
• Use checklists – For chemotherapy, always document start time, stop time, and drug details.
• Pair ICD-10 and CPT correctly – Diagnoses like malignant neoplasm of breast (C50.9) must be paired with chemo administration codes.
• Leverage technology – Use coding software and scrubbers to catch mismatches before submission.
• Educate providers – Proper documentation starts with physicians and nursing staff noting time, drug, and route accurately.