Do we perform routine computed tomography (CT) imaging on a patient who has achieved remission from lymphoma?

Routine CT Imaging is Not Recommended for Lymphoma Patients in Remission

Routine surveillance CT imaging is not recommended for patients who have achieved remission from lymphoma as it does not improve survival outcomes and leads to unnecessary radiation exposure, false positives, and healthcare costs.

Evidence Against Routine Surveillance Imaging

The Lugano Classification guidelines from the Journal of Clinical Oncology (2014) explicitly discourage routine surveillance scans for lymphoma patients in remission 1. These guidelines, which represent international consensus, state that:

• Published studies fail to support routine surveillance scans
• False-positive rates with PET scans exceed 20%, leading to unnecessary investigations, radiation exposure, biopsies, expense, and patient anxiety
• Follow-up scans should be prompted by clinical indications rather than performed on a routine schedule

The European Association of Nuclear Medicine (EANM) consensus recommendations (2023) strongly agree that during follow-up of lymphoma, routine imaging should not be performed 1. The panel reached consensus to disagree with performing:

• Routine CECT or MRI for up to 3 years
• Routine ultrasound
• Routine [¹⁸F]FDG-PET-CT for up to 3 years

Clinical Follow-up Approach

Instead of routine imaging, guidelines recommend:

1. Regular clinical evaluation:

   • For curable lymphomas (like DLBCL and Hodgkin lymphoma): visits every 3 months for first 2 years, every 6 months for next 3 years, then annually 1
   • For incurable lymphomas (like follicular lymphoma): visits every 3-6 months based on risk factors and response to treatment 1

2. Laboratory monitoring:

   • Complete blood count
   • Metabolic panel
   • Serum lactate dehydrogenase (LDH) 1

3. Imaging only when clinically indicated:

   • New or worsening symptoms
   • Abnormal physical examination findings
   • Concerning laboratory results

Limited Exceptions for Imaging

There are specific situations where limited follow-up imaging may be considered:

1. Indolent lymphomas with residual disease: In patients with indolent lymphomas who have residual intra-abdominal or retroperitoneal disease after therapy, judicious use of scans can be considered 1

2. Suspected relapse: When relapse is clinically suspected, imaging is recommended 2. The EANM consensus strongly agrees that in patients with suspected lymphoma relapse, CECT/MRI and [¹⁸F]FDG-PET-CT should be performed 1

Evidence on Detection and Outcomes

Multiple studies demonstrate the limited value of routine surveillance imaging:

• Only 5.7% of relapses were detected in asymptomatic patients using surveillance CT scans 3
• 56% of relapses occurred with symptoms outside the surveillance interval despite regular imaging 2
• Detection of asymptomatic relapse using surveillance CT did not improve overall or post-relapse survival 2
• No subgroups were identified that benefited from surveillance CT to detect relapse 2
• The cost to detect a single event was approximately $100,000 4
• Radiation exposure to detect a single event was 146.6 millisieverts per patient 4

Conclusion

The evidence strongly supports that routine surveillance imaging for lymphoma patients in remission has limited clinical value while exposing patients to unnecessary radiation, anxiety from false positives, and significant healthcare costs. Clinical follow-up with history, physical examination, and laboratory testing should be the cornerstone of surveillance, with imaging reserved for patients with clinical suspicion of relapse.