From the Guidelines
In oncology, a CT scan of the chest with contrast is the recommended initial imaging scan for patients with known or suspected lung cancer who are eligible for treatment. This recommendation is based on the American College of Chest Physicians evidence-based clinical practice guidelines 1. The guidelines suggest that a thorough clinical evaluation should be performed to provide an initial definition of tumor stage, and additional imaging for metastases is recommended if the clinical evaluation is abnormal and no suspicious extrathoracic abnormalities are found on chest CT.
Some of the key indications for scans in oncology include:
- Initial cancer detection and staging
- Treatment planning and response assessment
- Monitoring disease progression or response
- Identifying metastases
The choice of imaging modality depends on the cancer type, location, clinical question, and patient factors such as allergies, kidney function, and ability to tolerate procedures. For example:
- CT scans are commonly used for lung, liver, and pancreatic cancers
- MRI is preferred for brain, spinal cord, liver, and pelvic tumors
- PET scans, often combined with CT (PET-CT), are useful for detecting metabolically active cancer cells and identifying metastases, particularly in lung, lymphoma, melanoma, head and neck, and colorectal cancers 1
- Ultrasound is useful for breast, thyroid, liver, and kidney cancers, and can guide biopsies
- Bone scans using technetium-99m detect bone metastases by highlighting areas of increased bone turnover
- Mammography remains the standard screening tool for breast cancer
It's worth noting that the agreement between actual use of PET/CT and literature-based recommendations is high in certain cancers, such as lung, lymphoma, melanoma, head and neck, and colorectal cancers, but sparse in others, such as gynaecological cancers 1. Therefore, the choice of imaging modality should be tailored to the individual patient and cancer type. A CT scan of the chest with contrast is a crucial initial step in the diagnosis and management of lung cancer, and additional imaging modalities can be used as needed to provide comprehensive information about cancer characteristics and guide treatment decisions.
From the Research
Scans Needed in Oncology
The following scans are commonly used in oncology for diagnosis, staging, and follow-up:
- Computed Tomography (CT) scans: used for lung cancer staging, particularly CT of the thorax 2
- Positron Emission Tomography (PET)/CT scans: used for evaluating lymph nodes and detecting distant metastases in lung cancer, and for staging head and neck cancer 2, 3
- Magnetic Resonance Imaging (MRI) scans: used for evaluating lung cancer, particularly with the use of contrast media, and for assessing brain metastases 2, 4
- Whole-Body Diffusion-Weighted Imaging (WB-DWI): used as an adjunct to other imaging modalities in the management of metastatic breast cancer 5
- Contrast-Enhanced Computed Tomography Angiography (CCA): used as an adjunct to other imaging modalities in the management of metastatic breast cancer 5
Indications for Scans in Oncology
The indications for scans in oncology include:
- Diagnosis and staging of lung cancer: CT and PET/CT scans are recommended for lung cancer staging 2
- Diagnosis and staging of head and neck cancer: different modalities of radiological imaging are used for pre-treatment planning and staging of the extent of disease 3
- Assessment of metastatic breast cancer: CT, PET/CT, MRI, WB-DWI, and CCA are used for staging and repeated evaluation of patients with metastatic breast cancer 5
- Assessment of brain metastases: MRI scans are used to identify brain metastasis originating from lung adenocarcinoma and breast cancer, and to assess epidermal growth factor receptor (EGFR) mutation and human epidermal growth factor receptor 2 (HER2) status 4
- Radiotherapy treatment planning: CT scans are used for radiotherapy treatment planning, and scan protocols can be adjusted to optimize image quality and patient dose 6