Imaging plays a major role in the diagnosis, treatment, and monitoring of patients with cancer. Guidelines used by Radiology Benefits Management companies (RBM) for approval determination primarily come from recommendations published by the National Comprehensive Cancer Network Imaging Appropriate Use Criteria (NCCN-AUC). These guidelines divide imaging into 5 categories:
• cancer screening
• diagnosis of suspected disease
• initial staging of confirmed diagnosis
• treatment response assessment and follow-up (re-staging)
NCCN criteria include both imaging modalities (e.g. ultrasound, CT, MRI, nuclear medicine scans, and PET scans) as well as imaging frequency. When physicians provide specific clinical information to RBM nurses, approval of scans can be approved “right out of the gate.” This blog will discuss what providers need to do to ensure rapid prior approval if imaging studies.
Pediatric Oncology Guidelines
Patients below the age of 18 at diagnosis often use guidelines specific to the pediatric population. Recommendations for imaging modalities, frequencies, and even cancer types may vary from adult oncology guidelines, so physicians should refer to pediatric guidelines when available.
Definitions of the major Phases for imaging for Oncology patients
1. Screening imaging: for patients at increased risk for a specific cancer in the absence of clinical signs or symptoms.
2. Suspected diagnosis: imaging requested to evaluate a suspicion of cancer but tissue confirmation is lacking.
3. Initial work-up and staging: Imaging after biopsy confirmation but prior to specific treatment.
4. Interim re-staging to determine treatment response: imaging during active treatment with chemotherapy, endocrine therapy or maintenance therapy. (a)
5. Re-staging of locally treated lesions: imaging performed to evaluate primary or metastatic lesions with ablation or embolization using radio-frequency, radioactive isotopes, microwave or chemotherapy. (b)
6. Re-staging with suspected recurrence: imaging requested when there is suspicion for progression or recurrence of known cancer based on clinical signs, symptoms, lab tests or basic imaging studies.
7. Surveillance: imaging performed in patients who are asymptomatic or have chronic stable symptoms and are not receiving active treatment. (c)
Reference Notes on Specific Phases
a. Interim re-staging frequency
• Repeating imaging during chemotherapy or immunotherapy should not be performed more often than every 2 cycles or every 6-8 weeks.
• Repeating imaging during endocrine/hormonal therapy should not be performed more often than every 3 months.
• Patients with measurable or metastatic disease being observed without therapy (chemo-holiday) or those with minimal metastatic disease on maintenance therapy, imaging should not be considered more often than 3 months or when new signs or symptoms suggest progression.
b. Re-staging of locally treated lesions (embolization or ablation):
• PET scan is not indicated for assessing response to embolization or ablation treatment
• PET scans: unless stated in the specific guideline, PET scans are not used in surveillance.
• Surveillance scans are not indicated for patients with a history of metastatic disease who have remained in complete response for 5 years from the time of diagnosis.
Patients declining standard treatment
• Patients who have declined standard oncologic treatment (but may be receiving hospice care, palliative care, or alternative therapies) are not candidates for advanced imaging.
• An exception is imaging for suspected disease and for initial staging for patients who are considering standard therapy. Standard therapy is defined as surgery, chemotherapy, radiotherapy, and immunotherapy.
CT for most initial staging, re-staging, and surveillance imaging
• The majority of imaging in oncology will be with CT with contrast, unless contraindicated.
• Shellfish allergy is not a contraindication to contrast
• Iodinated contrast allergy patients (and those with renal insufficiency) may have either CT without contrast OR MRI without and with contrast. MRI with Gadolinium may be used in patients with eGFR greater than 40.
Imaging performed prior to diagnosis should not be repeated prior to surgical resection of initiation of chemotherapy unless there is a delay of at least 6 weeks since previous imaging or there are new or significantly worsening clinical signs or symptoms.
Bone Scans and Bone Pain
• In patients with solid malignancies and bone pain, rising tumor markers, elevated alkaline phosphatase, evaluation of patients with suspected or known bony metastasis, nuclear bone scan (whole body) (78306) is recommended as the initial imaging study. In most cases, this study does not require prior authorization.
• Patients with stage IV cancer with new onset back pain may obtain MRI without and with contrast without a prior bone scan.
• Bone scan prior to advanced imaging (MRI) is not required in the following cases:
o Bone scan is not feasible or readily available
o Continued suspicion despite inconclusive or negative bone scan
o Neurological compromise
o Soft-tissue component suggested on other imaging or physical exam
o Suspected meningeal involvement
Use of Radiology Benefit Management Evidence-based Guidelines
Oncology guidelines are generally listed by organ involvement, however, each organ may be further subdivided by cancer cell type. For example, thyroid malignancies are divided into 3 categories, each with separate treatments and imaging schedules:
• Follicular, papillary, Hürthle Cell
Cancers that are histologically similar but located in different organs may be grouped together in the same guideline chapter. For example: the Neuroendocrine cancers are grouped into:
• Chest (lung or thymus carcinoid)
• Abdomen organs (neuroendocrine GI or pancreas).
Lesson #36: RBM guidelines are taken from many cancer resources, but when there are conflicts and inconsistencies, criteria from NCCN take precedent. Imaging for all cancers are divided into 5 phases each with separate imaging modalities and frequencies:
• suspected cancer
• initial staging