Which imaging modality is described as the most initial step to identify the source of a suspected malignancy?

Which imaging modality is described as the most initial step to identify the source of a suspected malignancy?

• A. CMP
• B. CT CHEST/ABD/PelVIS
• C. CBC
• D. PTHRP

Answer: (B)

Starting with imaging to locate the primary tumor is essential when a malignancy is suspected but the source is unknown. A CT scan of the chest, abdomen, and pelvis provides a comprehensive survey of the body, revealing masses, nodal enlargement, and organ involvement across many common primary sites. It also helps guide where to biopsy and how to stage disease. Laboratory tests like a comprehensive metabolic panel or complete blood count can show abnormalities or organ dysfunction related to cancer, but they do not pinpoint where a tumor originates. A marker such as PTH-related peptide can indicate paraneoplastic hypercalcemia, but it doesn’t localize the primary source. Therefore, cross-sectional imaging that visually identifies tumors is the most appropriate initial step to locate the source of suspected malignancy.

Starting with imaging to locate the primary tumor is essential when a malignancy is suspected but the source is unknown. A CT scan of the chest, abdomen, and pelvis provides a comprehensive survey of the body, revealing masses, nodal enlargement, and organ involvement across many common primary sites. It also helps guide where to biopsy and how to stage disease.

Laboratory tests like a comprehensive metabolic panel or complete blood count can show abnormalities or organ dysfunction related to cancer, but they do not pinpoint where a tumor originates. A marker such as PTH-related peptide can indicate paraneoplastic hypercalcemia, but it doesn’t localize the primary source. Therefore, cross-sectional imaging that visually identifies tumors is the most appropriate initial step to locate the source of suspected malignancy.