Is a CT Scan Always Needed After Chemoradiation for Lung Cancer?

The standard is to test before immunotherapy

• Stage IIIB NSCLC treatment starts with chemoradiation, followed by immunotherapy
• A CT scan two to three weeks after treatment can ensure the patient isn’t progressing, and identify pneumonitis
• The PACIFIC study found that patients who started immunotherapy soon after chemoradiation derived the most benefit

For patients with stage IIIB non-small cell lung cancer (NSCLC), treatment may start with chemoradiation. If the cancer remains under control after two or three of these treatments, durvalumab (brand name: Imfinzi) therapy can help keep it from progressing. Is it always necessary to do a post-treatment CT scan before prescribing Imfinzi?

“In reality you could, but it doesn’t happen in my practice,” Dr. Balazs Halmos, medical oncologist and director of the Thoracic Oncology Program at Montefiore Medical Center, tells SurvivorNet Connect.

He offers two reasons for the scan. One is to make sure the patient isn’t progressing. The other is to have a baseline on any evolving radiation pneumonitis. If drug-induced pneumonitis becomes a question in the future, the scan can be used for comparison. “For those two very specific reasons, the standard of care at our institution is giving a CT scan very soon after chemoradiation—two to three weeks or so,” he says.

The timing of the CT scan is based on a subset analysis of the PACIFIC study, which found that patients who were able to start immunotherapy soon after chemoradiation seemed to have a greater benefit than patients who started later. “Maybe patients who could start early were healthier…and they tolerated chemoradiation better,” he adds. “But that significant benefit difference is notable enough that, if you have a patient who did really well after chemoradiation, there’s no particular reason for them to wait longer to get that scan.”