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Intensity Modulated Radiation Therapy
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Defines Aetna's clinical policy on when IMRT (including placement of fiducial markers and image-guidance) is considered medically necessary, lists applicable CPT/HCPCS/ICD-10 codes, and provides background/evidence discussion for various tumor sites. This is part 1 of 3 and contains policy statements, code lists, and background evidence summaries.
No material clinical/coverage changes reported in this policy update.
Coverage Summary
Policy 0590 (effective 02/12/2002; last reviewed 09/07/2023; next review 06/27/2024) covers Intensity‑Modulated Radiation Therapy (IMRT) and related services. The policy stance is covered with criteria: IMRT (and placement of fiducial markers or use of inter-/intrafraction image guidance) is medically necessary only when specified selection criteria are met. Key threshold definitions include: IMRT is defined as radiation therapy requiring highly sophisticated planning using numerous beamlets to meet dose requirements to tumor and organs at risk; and a critical‑structure benefit is present when IMRT would reduce the probability of grade 2 or 3 radiation toxicity versus 3D CRT in greater than 15% of similar cases. Dose thresholds for certain sites are specified (e.g., esophagus, gallbladder, pancreas: planned dose > 50 Gy).
Medical-Necessity Criteria
Medical Necessity
Aetna considers the following interventions medically necessary:
Medical Necessity - required items
- IMRT requirement: Intensity modulated radiation therapy (IMRT) for certain indications where critical structures cannot be adequately protected with standard 3-dimensional (3D) conformal radiotherapy
Policy statement
- Fiducial markers: Placement of fiducial markers if the above criteria are met, and the radiation target is not clearly visible, and bony anatomy is not sufficient for adequate target alignment
Placement permitted only if IMRT criteria are met
- Image guidance: Interfraction image guidance or intrafraction image guidance systems (e.g., Calypso 4D Localization System, RayPilot System) for delivering IMRT and other conformal radiotherapy
Includes systems for continuous intrafraction tracking
Medically Necessary Indications (Appendix)
IMRT is medically necessary for the following disease-site specific indications when concern exists about damage to surrounding critical structures compared with external beam or 3D conformal radiotherapy:
Medically necessary indications (appendix)
- Anal cancer
- Anaplastic thyroid cancer
- Brain tumors near critical structures: Brain tumors in close proximity to critical structures
- Esophageal cancer (dose): Esophageal cancer> 50 Gy
Dose must exceed 50 Gy
- Gallbladder cancer (dose): Gallbladder cancer> 50 Gy
Dose must exceed 50 Gy
- Head and neck cancer excluding T1/T2 glottic: Head and neck cancer excluding T1 and T2 glottic cancer
- Left breast near heart: Left breast cancer if the lesion is in close proximity to the heart or other cardiovascular structures, where 3D CRT would exceed acceptable constraints
Document proximity to heart/cardiovascular structures
- Lung cancer near critical structures: Lung cancer if the lesion is in close proximity to the heart or other critical structures
- Pancreatic cancer (dose): Pancreatic cancer> 50 Gy
Dose must exceed 50 Gy
- Postoperative pelvic radiation for endometrial cancer: Postoperative radiation to pelvis for endometrial cancer
- Prostate cancer
- T4 rectal cancer with nodal chains: T4 rectal cancer where the treating volume incorporates the external iliac and inguinal lymph node chains
Clinical Indications/Considerations (ASTRO coding guide summary)
Situational clinical indications (per ASTRO coding guide) where IMRT planning may be clinically indicated include one or more of the following:
Clinical indications/considerations
- Prior adjacent irradiation: An immediately adjacent area has been previously irradiated and abutting portals must be established with high precision
- Dose escalation is planned to deliver radiation doses in excess of those commonly utilized for similar tumors with conventional treatment
- Concave/convex target geometry: The target volume is concave or convex, and the critical normal tissues are within or around that convexity or concavity
- Proximity to critical structures: The target volume is in close proximity to critical structures that must be protected
- Narrow margins required: The volume of interest must be covered with narrow margins to adequately protect immediately adjacent structures
Tumor sites commonly supporting IMRT (ASTRO list)
Sites most commonly supporting the use of IMRT (ASTRO list) include any of the following:
Tumor sites commonly supporting IMRT
- Prostate carcinoma: Carcinoma of the prostate
- CNS tumors: Primary, metastatic or benign tumors of the central nervous system, including the brain, brain stem, and spinal cord
- Spine tumors: Primary, metastatic tumors of the spine where spinal cord tolerance may be exceeded by conventional treatment
- Head and neck lesions: Primary, metastatic or benign lesions to the head and neck area (aerodigestive tract, orbits, salivary glands, sinuses, skull base)
- Re-irradiation that meets requirements for medical necessity (as noted above)
- Selected thoracic/abdominal malignancies: Selected thoracic and abdominal malignancies
- Selected breast cancers with close proximity to critical structures
- Pelvic and retroperitoneal tumors: Other pelvic and retroperitoneal tumors that meet requirements for medical necessity
Not Medically Necessary / Experimental
Not Medically Necessary / Experimental
Exclusions: IMRT is considered experimental, investigational, and not medically necessary for the following:
Not medically necessary / experimental
- Right breast: IMRT is considered experimental and not medically necessary for right breast cancer
- Other indications not listed: IMRT is considered experimental and investigational for all other indications not listed as medically necessary
Coding
| 32553 | Placement of interstitial device(s) for radiation therapy guidance (eg, fiducial markers, dosimeter), percutaneous, intra-thoracic, single or multiple. |
| 49327 | Laparoscopy, surgical; with placement of interstitial device(s) for radiation therapy guidance (eg, fiducial markers, dosimeter), intra-abdominal, intrapelvic, and/or retroperitoneum, including imaging guidance, if performed, single or multiple (List separately in addition to code for primary procedure). |
| 49411 | Placement of interstitial device(s) for radiation therapy guidance (eg, fiducial markers, dosimeter), percutaneous, intra-abdominal, intra-pelvic (except prostate), and/or retroperitoneum, single or multiple. |
| 49412 | Placement of interstitial device(s) for radiation therapy guidance (eg, fiducial markers, dosimeter), open, intra-abdominal, intrapelvic, and/or retroperitoneum, including image guidance, if performed, single or multiple (List separately in addition to code for primary procedure). |
| 77301 | Intensity modulated radiotherapy planning, including dose-volume histograms for target and critical structure partial tolerance specifications. |
| 77338 | Multi-leaf collimator (MLC) device(s) for intensity modulated radiation therapy (MRT), design and construction per IMRT plan. |
| 77385 | Intensity modulated radiation treatment delivery (IMRT), includes guidance and tracking, when performed. |
| 77386 | Intensity modulated radiation treatment delivery (IMRT), includes guidance and tracking, when performed. |
| 77387 | Guidance for localization of target volume for delivery of radiation treatment delivery, includes intrafraction tracking, when performed. |
| A4648 | Tissue marker, implantable, any type, each. |
| C9728 | Placement of interstitial device(s) for radiation therapy/surgery guidance (eg, fiducial markers, dosimeter), for other than the following sites (any approach): abdomen, pelvis, prostate, retroperitoneum, thorax, single or multiple. |
| G6015 | Intensity modulated treatment delivery, single or multiple fields/arcs, via narrow spatially and temporally modulated beams, binary, dynamic MLC, per treatment session. |
| G6016 | Compensator-based beam modulation treatment delivery of inverse planned treatment using 3 or more high resolution (milled or cast) compensator, convergent beam modulated fields, per treatment session. |
| G6017 | Intra-fraction localization and tracking of target or patient motion during delivery of radiation therapy (e.g., 3D positional tracking, gating, 3D surface tracking), each fraction of treatment. |
| C00.0-D49.9 | Neoplasms (range) |
| Z51.0 | Encounter for antineoplastic radiation therapy |
| No codes listed |
Provider Actions
Medical necessity requirement
IMRT is authorized only for the indications listed as medically necessary in the policy. Providers must document why IMRT is required for the case — e.g., proximity of the target to critical structures, prior irradiation requiring abutting portals, need for dose escalation, concave/complex target geometry, or other rationale demonstrating that 3D CRT cannot adequately protect critical structures.
Apply eviCore radiation therapy clinical guidelines
Follow eviCore Healthcare Radiation Therapy Clinical Guidelines for medical necessity criteria. eviCore determines the specific indications and selection criteria for IMRT and is the reference for prior authorization decisions.
Justify fiducial marker placement
Placement of fiducial markers is permitted only when IMRT medical necessity criteria are met and when the radiation target is not clearly visible and bony anatomy is insufficient for adequate target alignment. Document the clinical justification and include the applicable procedure codes.
Use of image guidance with IMRT
Interfraction and intrafraction image-guidance systems used with IMRT (e.g., Calypso, RayPilot) are considered medically necessary when delivering IMRT or other conformal radiotherapy that meets policy criteria. Document use of tracking/localization per fraction and report applicable guidance codes (e.g., G6017, 77387) where performed.
Dose and anatomic rationale
For indications that depend on dose or anatomy, document the planned dose or anatomic relationship: for esophagus, gallbladder, or pancreas, record that the planned dose exceeds 50 Gy; for left-breast cases, document the lesion's proximity to the heart or cardiovascular structures and that 3D CRT constraints would be exceeded.
Refer to full policy for coverage criteria and billing
Consult the complete Aetna Clinical Policy Bulletin 0590 for the full coverage criteria, prior authorization requirements, documentation expectations, and detailed coding information before submission or billing.
Background & Evidence
Background: IMRT is a highly sophisticated radiotherapy technique that uses inverse planning and numerous beamlets to produce highly conformal dose distributions that spare adjacent organs at risk. Delivery approaches include dynamic multileaf collimators (MLCs) that modulate beam intensity during treatment and compensator‑based techniques that use custom high‑density modulators to shape the beam. Fiducial markers (e.g., gold seeds, stainless steel screws, or electromagnetic transponders) may be implanted to improve target localization when the target is not clearly visible and bony anatomy is insufficient. Potential benefits include improved critical‑structure sparing and the ability to escalate dose or treat complex/concave targets; potential risks include increased whole‑body or low‑dose exposure with theoretical higher secondary malignancy risk, the possibility of geographic miss with overly tight margins, and added imaging exposure from frequent image guidance. Because IMRT planning and delivery are technically demanding, appropriate expertise, image‑guidance, and quality assurance are required and some uses are recommended to be limited to experienced centers.
| Study/Guidance | Key finding |
|---|---|
| KCE assessment (Van den Steen et al, 2007) | Found weak-to-moderate evidence of toxicity reduction in head/neck, prostate, breast; recommended restriction to experienced centers and need for more long-term data; noted potential increased secondary malignancy risk. |
| Pignol et al (2008) — RCT in breast cancer | BIMRT reduced acute skin toxicity (moist desquamation) compared with wedge compensation. |
| Donovan et al (2007) — RCT in breast cancer | BIMRT associated with fewer late adverse effects and better cosmetic outcomes versus wedge compensation/2D RT. |
| Romesser et al (2021) — prospective phase II, thyroid cancer | IMRT ± concurrent doxorubicin showed 2-year locoregional PFS 79.7%; CC-IMRT had less locoregional failure in post-hoc analysis but small nonrandomized sample (n=27). |
| Wu et al (2022) — phase II neoadjuvant IMRT in centrally located HCC | Promising 1-, 3-, 5-year OS (94.6%, 75.4%, 69.1%) with acceptable toxicity in single-arm trial (n=38). |
| ASTRO coding guide / expert panels | Lists common indications supporting IMRT (prostate, CNS, head/neck, select breast, selected thoracic/abdominal, pelvic/retroperitoneal tumors) and clinical planning considerations. |
Definitions
Revision History
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