NSCLC: Optimal Imaging Following CRT

Mark A. Socinski, MD:The patient got through therapy and had a partial response; that’s typical. Now I always caution patients regarding that first CT [computed tomography] scan. Because the first thing patients want to know after completing chemoradiation is, did it work? And I counsel them and say, “Well, in that first CT scan, the CT scan’s going to be hard to interpret because we see a lot of changes as a result of the radiation, so you can’t be certain; you can suspect that much of what you may see on the CT scan may be the result of the radiation and not the cancer.”

I saw a patient this week in my practice who finished his chemoradiation about 3 weeks ago. He had a CT scan about 3 or 4 days ago. I saw him yesterday in my practice, and I reviewed his CT scan for him. And the area where I knew his cancer was, actually looked better. But around the cancer in the field of radiation, he had many nodules that were there that I don’t think are related to the cancer. I think they’re a result of the radiation. I think with time, as we see with most radiation changes, they resolve or improve. So I was very confident that this patient did not have evidence of disease progression. But that’s observation based on 25 years of experience in treating these patients and looking at CT scans in these stage III patients as a result of radiation and making that judgment call.

With regard to follow-up in evaluation of this patient, I can tell you that prior to the PACIFIC data, what I would typically do—as I mentioned before, radiation can cause changes in the CT scan—was wait 2 months to get the first CT scan following completion of chemoradiotherapy [CRT]. If that scan looked OK, I would do another scan at 6 months. If that scan looked OK, I would do another scan at 1 year. There are no specific guidelines with regard to surveillance. I would avoid doing PET [positron emission tomography] scans in these patients, and that’s typically what I would do prior to the PACIFIC data.

Now the PACIFIC data changed that because what the PACIFIC trial did is really mandate that patients receive durvalumab within 6 weeks of treatment. And it also demanded that patients had evidence of no disease progression. So you had to do a CT scan to make sure that the cancer wasn’t worse. And you had to do that within 6 weeks, or I would argue within 4 weeks or 2 weeks, because it does take some time to get the drug authorized and get the patient scheduled for the infusion and all those sort of things. We want to start them on immunotherapy before 6 weeks.

So in getting a CT scan scheduled, getting it read and evaluated, seeing the physician, getting the drug authorized, and getting the infusion scheduled, you have to account that that’s a 2-week process. So really all things being equal, because of the PACIFIC trial, my practice has changed from doing the CT at 2 months to doing a CT between 2 and 4 weeks following completion of chemoradiotherapy.

Transcript edited for clarity.

Case: A 52-Year-Old Male With Stage IIIA NSCLC

Initial presentation

• A 52-year-old man presented with a 15-lb weight loss and worsening dyspnea
• PMH: HTN
• SH: Computer programmer; Smoked a pack/day for 30 years; Quit smoking 2 years ago; Married with 4 kids
• PE: Unremarkable

Clinical workup

• Imaging:
  • Initial CT showed a 5-cm left upper lobe mass with aortopulmonary window and left paratracheal adenopathy measuring up to 2.5 cm
  • Subsequent PET scan showed activity in the left upper lobe mass and all nodal areas
  • No extrathoracic disease was identified
  • MRI showed no brain metastases
• Mediastinal sampling: EBUS was performed and documented squamous carcinoma in the left paratracheal lymph nodes
• Staging: T2N2M0
• ECOG PS 1
• Multidisciplinary tumor board deemed his tumor unresectable due to multistation N2 disease

Treatment

• Concurrent cisplatin/etoposide with external-beam radiotherapy
• Repeat CT 4 weeks after completion of concurrent chemoradiotherapy showed a PR with no new sites of disease