What is the next diagnostic test for a 60-year-old male with Hodgkin's lymphoma and normal computed tomography (CT) scans of the chest, abdomen, and pelvis, without constitutional symptoms and normal blood work, who has well-controlled diabetes mellitus (DM)?

Next Diagnostic Test for Hodgkin's Lymphoma Patient with Normal CT Scans

The next test that should be performed for this 60-year-old male with Hodgkin's lymphoma and normal CT scans is a whole-body positron emission tomography (PET) scan. 1

Rationale for PET Scan

According to the ESMO Clinical Practice Guidelines, a baseline whole-body PET scan is mandatory in the diagnostic workup for Hodgkin's lymphoma when available. This recommendation is based on several key factors:

• PET provides superior sensitivity for detecting disease involvement compared to CT alone
• PET establishes a baseline for subsequent response assessment
• PET can identify disease that may be missed by conventional CT imaging
• PET results may alter staging and subsequent treatment decisions

Clinical Context for This Patient

For this 60-year-old male patient with:

• Well-controlled diabetes
• Normal chest, abdominal, and pelvic CT scans
• No constitutional symptoms (B symptoms)
• Normal blood work

A PET scan is particularly important because:

1. It can detect metabolically active disease that may not be apparent on anatomical imaging (CT)
2. It may identify extranodal involvement not visible on CT
3. It eliminates the need for bone marrow biopsy if performed 1

Complete Diagnostic Workup

The ESMO guidelines outline a comprehensive diagnostic workup that includes:

• Medical history and physical examination
• Chest X-ray (already completed)
• Contrast-enhanced CT scan of neck, chest, and abdomen (already completed)
• PET scan (recommended next step)
• Full blood count and blood chemistry (already completed)
• Screening for hepatitis B, hepatitis C, and HIV 1

Pretreatment Examinations

After completing the diagnostic workup with PET scan, the following pretreatment examinations should be performed:

• ECG
• Echocardiography
• Pulmonary function tests
• Reproductive counselling (if applicable)

Bone Marrow Biopsy Considerations

It's important to note that if PET-CT is performed, a bone marrow biopsy is no longer indicated due to the high sensitivity of PET-CT for bone marrow involvement 1. However, if PET-CT is not available, then a bone marrow biopsy would be necessary, especially in advanced stage disease 1.

Clinical Pitfalls to Avoid

1. Don't skip PET imaging: Relying solely on CT scans may miss metabolically active disease and lead to understaging.

2. Don't perform unnecessary bone marrow biopsy: If PET-CT is performed, bone marrow biopsy is generally not needed unless there are specific clinical indications.

3. Don't delay pretreatment cardiac and pulmonary function tests: These are essential before starting treatment, especially given the patient's age and diabetes history.

4. Don't forget hepatitis and HIV screening: These are mandatory according to guidelines and impact treatment decisions 1.

PET imaging has become an essential component in the management of Hodgkin's lymphoma, providing crucial information for accurate staging, treatment planning, and subsequent response assessment 2, 3.