Coding Ahead
CasePilot
Medical Coding Assistant
CaseConsultant
Instant Email Coding Consultant
Case2Code
Search and Code Lookup Tool
CareerCenter
Medical Coding Job Board
Log in Register free account

Need help choosing the right code?

Ask CasePilot about procedures, modifiers, bundling, and coding guidance.

Try CasePilot

Official Description

Hyperthermia, externally generated; superficial (ie, heating to a depth of 4 cm or less)

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

Hyperthermia, as defined by CPT® Code 77600, refers to a medical procedure that involves the externally generated elevation of temperature in a targeted area, specifically to a depth of 4 centimeters or less. This technique is primarily utilized to treat superficial or subcutaneous tumor cells while minimizing damage to the surrounding healthy tissue. The procedure is based on the principle that tumor cells exhibit heightened sensitivity to increased temperatures compared to normal cells. By raising the temperature of these malignant cells, hyperthermia can enhance the therapeutic effects of concurrent treatments such as radiation and chemotherapy. Additionally, the procedure may stimulate the immune system's components, which play a crucial role in the destruction of abnormal cells. The heat required for this treatment can be generated through various methods, including microwave, radiofrequency, or ultrasound, and is applied to a precisely defined area using specialized applicators. Typically, hyperthermia therapy is administered 1 to 2 times per week, culminating in a total of 10 to 12 treatment sessions. Following each session, tumor cells may develop thermotolerance within 8 to 12 hours, with the temperature gradually returning to normal levels over the course of 2 to 4 days. The code 77600 encompasses not only the hyperthermia treatment itself but also the management of the treatment course, the physics planning involved, the insertion of temperature sensors, and the utilization of heat-generating sources.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The procedure of externally generated hyperthermia, as described by CPT® Code 77600, is indicated for various conditions, particularly those involving tumor cells. The following are the explicitly provided indications for this treatment:

  • Primary Tumors Hyperthermia may be utilized to treat primary tumors that are accessible and can benefit from localized temperature elevation.
  • Metastatic Tumors This procedure is also indicated for metastatic tumors, where cancer has spread from its original site to other areas of the body.
  • Recurring Melanoma Hyperthermia can be effective in managing recurring melanoma, especially when it presents in superficial locations.
  • Recurrent Breast Cancer The treatment is indicated for recurrent breast cancer located in the chest wall, where targeted heat application can assist in tumor management.
  • Cervical Lymph Node Metastases Hyperthermia is indicated for cervical lymph node metastases resulting from head or neck malignancies, providing a localized treatment option.

2. Procedure

The procedure for externally generated hyperthermia involves several critical steps, each designed to ensure effective treatment while safeguarding surrounding healthy tissue. The following procedural steps are outlined:

  • Step 1: Treatment Planning Initially, a comprehensive treatment plan is developed, which includes identifying the target area for hyperthermia application. This planning phase may involve imaging studies to accurately locate the tumor and assess its characteristics.
  • Step 2: Insertion of Temperature Sensors Temperature sensors are strategically inserted into the treatment area to monitor the temperature of both the tumor and surrounding tissues. This step is crucial for ensuring that the temperature is elevated adequately to affect the tumor cells while avoiding damage to normal cells.
  • Step 3: Application of Heat The heat is then applied to the targeted area using specialized applicators that generate microwave, radiofrequency, or ultrasound energy. The applicators are positioned to deliver the heat uniformly across the tumor, ensuring effective treatment.
  • Step 4: Monitoring During Treatment Throughout the procedure, continuous monitoring of the temperature is conducted to maintain the desired therapeutic range. Adjustments may be made to the heat application based on real-time feedback from the temperature sensors.
  • Step 5: Post-Treatment Assessment After the heat application is complete, a post-treatment assessment is performed to evaluate the immediate effects of the procedure. This may include follow-up imaging or clinical evaluations to determine the response of the tumor to the hyperthermia treatment.

3. Post-Procedure

Following the hyperthermia treatment, patients may experience a recovery period during which the body gradually returns to its normal temperature. It is expected that tumor cells will develop thermotolerance within 8 to 12 hours after the session, which may influence the timing of subsequent treatments. The normal temperature of the treated area typically returns within 2 to 4 days. During this recovery phase, patients are monitored for any potential side effects or complications, and follow-up appointments are scheduled to assess the overall effectiveness of the treatment. Additionally, ongoing management of the treatment course, including any necessary adjustments to the overall cancer treatment plan, is essential for optimizing patient outcomes.

Short Descr HYPERTHERMIA EXT GEN SUPFC
Medium Descr HYPERTHERMIA EXTERNALLY GENERATED SUPERFICIAL
Long Descr Hyperthermia, externally generated; superficial (ie, heating to a depth of 4 cm or less)
Status Code Restricted Coverage
Global Days XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC) 1 - Diagnostic Tests for Radiology Services
Multiple Procedures (51) 0 - No payment adjustment rules for multiple procedures apply.
Bilateral Surgery (50) 0 - 150% payment adjustment for bilateral procedures does NOT apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 0 - Payment restriction for assistants at surgery applies to this procedure...
Co-Surgeons (62) 0 - Co-surgeons not permitted for this procedure.
Team Surgery (66) 0 - Team surgeons not permitted for this procedure.
Diagnostic Imaging Family 99 - Concept Does Not Apply
APC Status Indicator Procedure or Service, Not Discounted when Multiple
ASC Payment Indicator Radiology service paid separately when provided integral to a surgical procedure on ASC list; payment based on OPPS relative payment weight.
Type of Service (TOS) 6 - Therapeutic Radiology
Berenson-Eggers TOS (BETOS) P7B - Oncology - other
MUE 1
CCS Clinical Classification 211 - Therapeutic radiology
XS Separate structure, a service that is distinct because it was performed on a separate organ/structure
59 Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25.
79 Unrelated procedure or service by the same physician or other qualified health care professional during the postoperative period: the individual may need to indicate that the performance of a procedure or service during the postoperative period was unrelated to the original procedure. this circumstance may be reported by using modifier 79. (for repeat procedures on the same day, see modifier 76.)
26 Professional component: certain procedures are a combination of a physician or other qualified health care professional component and a technical component. when the physician or other qualified health care professional component is reported separately, the service may be identified by adding modifier 26 to the usual procedure number.
GC This service has been performed in part by a resident under the direction of a teaching physician
GV Attending physician not employed or paid under arrangement by the patient's hospice provider
Q6 Service furnished under a fee-for-time compensation arrangement by a substitute physician or by a substitute physical therapist furnishing outpatient physical therapy services in a health professional shortage area, a medically underserved area, or a rural area
76 Repeat procedure or service by same physician or other qualified health care professional: it may be necessary to indicate that a procedure or service was repeated by the same physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 76 to the repeated procedure or service. note: this modifier should not be appended to an e/m service.
AG Primary physician
Q1 Routine clinical service provided in a clinical research study that is in an approved clinical research study
RT Right side (used to identify procedures performed on the right side of the body)
Date
Action
Notes
2025-01-01 Changed Short and Medium Descriptions changed.
2017-01-01 Changed Moderate (Conscious) Sedation flag removed. See new Moderate Sedation category.
Pre-1990 Added Code added.
Code
Description
Code
Description
Code
Description
CasePilot

Get instant expert-level medical coding assistance.

Ask about:
CPT Codes Guidelines Modifiers Crosswalks NCCI Edits Compliance Medicare Coverage
Example: "What is CPT code 99213?" or "Guidelines for E/M services"