Radiation Oncology Billing 2026: New Delivery Codes and Denial Prevention

By Rcmaxis Revenue Cycle Team  ·  August 2026  ·  15 min read

If your practice bills radiation therapy the same way it did in 2025, you're billing it wrong starting this year. CPT didn't just tweak a few descriptors for 2026 — it deleted the treatment delivery codes radiation oncology has used for years and replaced them with a three-tier complexity structure that applies the same way whether the treatment happens in a hospital outpatient department or a freestanding center. That's a genuine site-neutral coding change, and payers adopting it at different speeds is already creating real reimbursement gaps for practices that haven't adjusted.

Layer on top of that a decade of OIG audit findings averaging into the hundreds of millions of dollars, a CMS payment model that was announced, delayed repeatedly, and ultimately shelved without ever taking effect, and a reimbursement trend that's landed harder on practices than CMS's own projections suggested — and radiation oncology billing in 2026 has more moving parts than most specialties are tracking.

The 2026 Delivery Code Overhaul: 77402, 77407, 77412

This is the headline change and it affects every radiation oncology claim going forward. CPT deleted code 77401, Category III code 0394T, technical-component codes 77014, 77385, and 77386, and the Medicare-only G6001 through G6017 delivery G-codes. In their place: three consolidated codes based purely on delivery complexity, not on whether the treatment is 3D-CRT or IMRT.

Code 77387, previously covering image guidance for target localization, becomes a professional-component-only code as of 2026 — its technical component now folds into the new consolidated delivery codes above rather than being billed separately. If your billing system or coding team is still mapping claims to the old 3D-CRT-versus-IMRT logic, every claim going out the door right now is running on outdated code selection logic.

Treatment Planning, Simulation and Brachytherapy Codes

The planning and simulation codes sit alongside the new delivery codes and haven't changed as dramatically, but they're where a lot of routine billing errors still happen. Treatment planning uses 77261 through 77263 depending on complexity — simple, intermediate, or complex based on the number of treatment areas, ports, and blocking required — and only one unit is billable per episode of care regardless of which level applies.

The CMS Radiation Oncology Model: What Actually Happened

If you've heard of the CMS Radiation Oncology Model and assumed it's operating somewhere, it isn't — and it never has been. CMS finalized the model in 2020 with a January 2022 start date, designed to test mandatory, prospective, site-neutral, episode-based bundled payments for a 90-day radiotherapy episode across specified cancer types. Congress statutorily blocked implementation before it started, CMS modified the model in November 2021 to remove liver cancer and brachytherapy from scope, Congress delayed it again to no earlier than 2023, and in August 2022 CMS issued a final rule delaying it indefinitely "to a date to be determined through future rulemaking." No restart date has been announced since.

What's actually alive right now is different legislation: the bipartisan ROCR Value-Based Program Act, which would direct CMS to establish an episode-based case-rate payment program through statute rather than CMMI rulemaking. ASTRO cites a 23 percent Medicare reimbursement decline for radiation oncology over the past decade as the problem ROCR is meant to address, and advocacy materials project it could save Medicare roughly $200 million over ten years. As of this writing it remains pending in Congress, not enacted — worth watching, not something to bill against yet.

Prior Authorization for Advanced Radiation Therapy

Advanced radiation therapy modalities — IMRT, SBRT, proton therapy — commonly require prior authorization, and eviCore is the most well-documented vendor managing this on behalf of payers including Aetna, Independence Administrators, 1199 SEIU, and Blue Cross Blue Shield of Montana, among others. eviCore publishes payer-specific Radiation Oncology Coding Manuals with CPT code lists that get updated annually, which means a practice can't assume last year's prior auth code list still applies this year — it has to be checked per payer, every year.

OIG Audit History: A Decade of the Same Root Cause

Radiation oncology has one of the more consistent OIG audit patterns of any specialty, and it's worth understanding because it's still relevant to how MACs process claims today. In 2018, OIG found $25.8 million in IMRT planning overpayments, driven almost entirely by hospitals separately billing complex simulation code 77290 when it was already bundled into IMRT planning code 77301. In 2019, a broader review found $125.4 million in duplicate 3D-CRT planning payment savings opportunities across 1,379 hospitals between 2008 and 2017. A separate 2018 review found $7.2 million in unallowable advanced radiation therapy payments specifically at MAC Novitas Solutions.

On the reimbursement side, CMS's official 2026 Medicare Physician Fee Schedule estimate was a modest 1 percent aggregate cut to radiation oncology. ASTRO's own April 2026 member survey found a very different reality on the ground: more than two-thirds of radiation oncologists reported actual payment declines of 10 percent or more. That gap between the official projection and what practices are actually experiencing is worth flagging to your finance team directly — don't budget off the CMS aggregate number alone.