Oncologic Applications of Positron Emission Tomography Scanning

Section: Radiology
Effective Date: July 01, 2019
Revised Date: June 07, 2019
Last Reviewed: May 15, 2019

Description

Positron emission tomography (PET) scans are based on the use of positron-emitting radionuclide tracers coupled to organic molecules, such as glucose, ammonia, or water. The radionuclide tracers simultaneously emit 2 high-energy photons in opposite directions that can be simultaneously detected (referred to as coincidence detection) by a PET scanner, comprising multiple stationary detectors that encircle the area of interest.

The utility of PET scanning for the diagnosis, staging and restaging, and surveillance of malignancies varies by type of cancer. In general, PET scanning can distinguish benign from malignant masses in certain circumstances and improve the accuracy of staging by detecting additional disease not detected by other imaging modalities. Therefore, PET scanning for diagnosis and staging of malignancies can be considered medically necessary when specific criteria are met for specific cancers, as outlined in the policy statements. For follow-up after initial diagnosis and staging have been performed, there are a few situations in which PET can improve detection of recurrence, and lead to changes in management that improve the net health outcome.

Criteria

All policy statements apply to both positron emission tomography (PET) scans and PET plus computed tomography (CT) scans, ie, PET scans with or without PET/CT fusion. 

For the clinical situations indicated that may be considered medically necessary, this assumes that the results of the PET scan will influence treatment decisions. If the results will not influence treatment decisions, these situations would be considered not medically necessary. 

Bladder cancer

PET scanning may be considered medically necessary in the staging or restaging of muscle-invasive bladder cancer when CT or magnetic resonance imaging are not indicated or remained inconclusive on distant metastasis. 

PET scanning is considered investigational for bladder tumors that have not invaded the muscle (stage <cT2). 

Bone Sarcoma

PET scanning may be considered medically necessary in the staging or restaging of Ewing sarcoma and osteosarcoma. 

PET scanning is considered investigational in the staging of chondrosarcoma. 

Brain Cancer

PET scanning may be considered medically necessary in the staging or restaging of brain cancer. 

Breast Cancer

PET scanning may be considered medically necessary in the staging or restaging of breast cancer for the following application: 

  • Detecting locoregional or distant recurrence or metastasis (except axillary lymph nodes) when suspicion of disease is high and other imaging is inconclusive. 

PET scanning is considered investigational in the evaluation of breast cancer for all other applications, including but not limited to the following: 

  • Differential diagnosis in patients with suspicious breast lesions or an indeterminate or low suspicion finding on mammography 
  • Staging axillary lymph nodes. 
  • Predicting pathologic response to neoadjuvant therapy for locally advanced disease. 

Cervical Cancer

PET scanning may be considered medically necessary in the initial staging of patients with locally advanced cervical cancer. 

PET scanning may be considered medically necessary in the evaluation of known or suspected recurrence. 

Colorectal Cancer

PET scanning may be considered medically necessary as a technique for 

  • Staging or restaging to detect and assess resectability of hepatic or extrahepatic metastases of colorectal cancer, and 
  • To evaluate a rising and persistently elevated carcinoembryonic antigen levels when standard imaging, including CT scan, is negative. 

PET scanning is considered investigational as: 

  • A technique to assess the presence of scarring vs local bowel recurrence in patients with previously resected colorectal cancer. 
  • A technique contributing to radiotherapy treatment planning. 

Endometrial Cancer

PET scanning is considered medically necessary in the: 

  • Detection of lymph node metastases, and 
  • Assessment of endometrial cancer recurrence. 

Esophageal Cancer

PET scanning may be considered medically necessary in the 

  • Staging of esophageal cancer, and 
  • Determining response to preoperative induction therapy. 

PET scanning is considered investigational in other aspects of the evaluation of esophageal cancer, including but not limited to the following applications: 

  • Detection of primary esophageal cancer. 

Gastric Cancer

PET scanning may be considered medically necessary in the: 

  • Initial diagnosis and staging of gastric cancer, and 
  • Evaluation for recurrent gastric cancer after surgical resection, when other imaging modalities are inconclusive. 

Head and Neck Cancer

PET scanning may be considered medically necessary in the evaluation of head and neck cancer in the 

  • Initial diagnosis of suspected cancer, 
  • Initial staging of disease, and restaging of residual or recurrent disease during follow-up, and 
  • Evaluation of response to treatment. 

Lung Cancer

PET scanning may be considered medically necessary for any of the following applications: 

  • Patients with a solitary pulmonary nodule as a single scan technique (not dual-time) to distinguish between benign and malignant disease when prior CT scan and chest x-ray findings are inconclusive or discordant, 
  • As staging or restaging technique in those with known non-small-cell lung cancer, and 
  • To determine resectability for patients with a presumed solitary metastatic lesion from lung cancer. 

PET scanning may be considered medically necessary in staging of small-cell lung cancer if limited stage is suspected based on standard imaging. 

PET scanning is considered investigational in staging of small-cell lung cancer if extensive stage is established and in all other aspects of managing small-cell lung cancer. 

Lymphoma, Including Hodgkin Disease

PET scanning may be considered medically necessary as a technique for staging lymphoma either during initial staging or for restaging at follow-up. 

Melanoma

PET scanning may be considered medically necessary as a technique for assessing extranodal spread of malignant melanoma at initial staging or at restaging during follow-up treatment for advanced disease (stage III or IV). 

PET scanning is considered investigational in managing stage 0, I, or II melanoma. 

PET scanning is considered investigational as a technique to detect regional lymph node metastases in patients with clinically localized melanoma who are candidates to undergo sentinel node biopsy. 

Multiple Myeloma

PET scanning may be considered medically necessary in the staging or restaging of multiple myeloma, particularly if the skeletal survey is negative. 

Neuroendocrine Tumors

PET scanning with gallium 68 may be considered medically necessary as a technique for staging neuroendocrine tumors either during initial staging or for restaging at follow-up. 

PET scanning with other radiotracers is considered investigational in all aspects of managing neuroendocrine tumors. 

Ovarian Cancer

PET scanning may be considered medically necessary in the evaluation of patients with signs and/or symptoms of suspected ovarian cancer recurrence (restaging) when standard imaging, including CT scan, is inconclusive. 

PET scanning is considered investigational in the initial evaluation of known or suspected ovarian cancer in all situations. 

Pancreatic Cancer

PET scanning may be considered medically necessary in the initial diagnosis and staging of pancreatic cancer when other imaging and biopsy are inconclusive. 

PET scanning is considered investigational as a technique to evaluate other aspects of pancreatic cancer. 

Penile Cancer

PET scanning is considered investigational in all aspects of managing penile cancer. 

Prostate Cancer

PET scanning with carbon 11 choline and fluorine 18 fluciclovine may be medically necessary for evaluating suspected or biochemically recurrent prostate cancer after primary treatment to detect small volume disease in soft tissues. 

PET scanning with gallium 68 is considered investigational in all aspects of managing prostate cancer. 

PET scanning for all other indications in known or suspected prostate cancer is considered investigational.

Renal Cell Carcinoma

PET scanning is considered investigational in all aspects of managing renal cancer. 

Soft Tissue Sarcoma

PET scanning is considered investigational in evaluation of soft tissue sarcoma, including but not limited to the following applications: 

  • Distinguishing between benign lesions and malignant soft tissue sarcoma, 
  • Distinguishing between low-grade and high-grade soft tissue sarcoma, 
  • Detecting locoregional recurrence, 
  • Detecting distant metastasis. 

PET scanning is considered medically necessary for evaluating response to imatinib and other treatments for gastrointestinal stromal tumors. 

Testicular Cancer

PET scanning may be considered medically necessary in evaluation of residual mass following chemotherapy of stage IIB and III seminomas. (The scan should be completed no sooner than 6 weeks after chemotherapy.) 

Except as noted above for seminoma, PET scanning is considered investigational in evaluation of testicular cancer, including but not limited to the following applications: 

  • Initial staging of testicular cancer, 
  • Distinguishing between viable tumor and necrosis/fibrosis after treatment of testicular cancer, and 
  • Detection of recurrent disease after treatment of testicular cancer. 

Thyroid Cancer

PET scanning may be considered medically necessary in the restaging of patients with differentiated thyroid cancer when thyroglobulin levels are elevated and whole-body iodine-131 imaging is negative. 

PET scanning is considered investigational in the evaluation of known or suspected differentiated or poorly differentiated thyroid cancer in all other situations. 

Cancer of Unknown Primary

PET scanning may be considered medically necessary in patients with a cancer of unknown primary who meet ALL of the following criteria: 

  • In patients with a single site of disease outside the cervical lymph nodes, and 
  • Patient is considering local or regional treatment for a single site of metastatic disease, and 
  • After a negative workup for an occult primary tumor, and 
  • PET scan will be used to rule out or detect additional sites of disease that would eliminate the rationale for local or regional treatment. 

PET scanning is considered investigational for other indications in patients with a cancer of unknown primary, including, but not limited to the following: 

  • As part of the initial workup of a cancer of unknown primary, and 
  • As part of the workup of patients with multiple sites of disease. 

Cancer Surveillance

PET scanning is considered investigational when used as a surveillance tool for patients with cancer or with a history of cancer. A scan is considered surveillance if performed more than 6 months after completion of cancer therapy (12 months for lymphoma) in patients without objective signs or symptoms suggestive of cancer recurrence (see Policy Guidelines section).

Policy Guidelines

As with any imaging technique, the medical necessity of positron emission tomography (PET) scanning depends in part on what imaging techniques are used before or after the PET scanning. Due to its expense, PET scanning is typically considered after other techniques, such as computed tomography (CT), magnetic resonance imaging (MRI), or ultrasonography, provide inconclusive or discordant results. In patients with melanoma or lymphoma, PET scanning may be considered an initial imaging technique. If so, the medical necessity of subsequent imaging during the same diagnostic evaluation is unclear. Thus, PET should be considered for the medically necessary indications above only when standard imaging (eg, CT, MRI) is inconclusive or not indicated.

Procedure Codes

78608 78609 78811 78812 78813 78814 78815
78816 A9515 A9526 A9552 A9580 A9587 A9588
A9598 G0219 G0235 G0252

Links

References (PDF)