Treatment Duration Considerations for CSCC

Transcript:

Sunandana Chandra, MD, MS: Dr Pavlick, what is your thought process on the duration of therapy? We’ve talked a lot about immunotherapy and we know that these responses can be durable. Is there ever a time where you may think of potentially stopping therapy and monitoring the patient? Can you expound on that?

Anna C. Pavlick, DO: Sure. There really are no guidelines when it comes to when to stop and how to stop. What was recently discussed at the last ASCO [American Society of Clinical Oncology annual meeting] was also looking at neoadjuvant therapy, giving 2 or 3 cycles, then taking these patients to the OR [operating room]. Quite remarkably, although many times there was not a big change radiographically, when these lesions were resected, they were all dead. So these patients who have a pathologic CR [complete response] are the ones that we know will go out to have these long-term durable responses.

But what do we do when it comes to patients who have locally advanced or metastatic disease? We know that you don’t want to keep people on immunotherapy forever. Most of the time, the most that we will stop treating patients is about 2 years. But what happens if you get someone with a very rapid response and complete resolution of their disease? I think those are the patients that perplex us the most.

Or those patients who have a very brisk response and then are left with what I will call schmutz on your CT scans, where you’ve got these very small nonspecific lesions that look like there’s still something there, but you don’t know whether that’s still active cancer. I think that’s when looking at PET [positron emission tomography] scans, just as we’ve done in melanoma. When can you say to stop in melanoma? Again, we don’t know there either, but there are some data to suggest that if you can do a PET scan on these patients with locally advanced and metastatic disease and they in fact have no FDG [fluorodeoxyglucose] uptake on their imaging, then you’re pretty confident in stopping therapy.

The other thing with the locally advanced tumors is that many times you can also do what’s called scouting biopsies in that area to determine if in fact there is any residual carcinoma that you’re just not visually able to see. So there are techniques. Everything I believe is very individualized for the patient and the extent of their disease, but there are no firm rules. You’ve got to tailor your stopping to patient responses as well as tolerability. Are the patients starting to develop significant toxicity? Many times it’s itching where they just can’t take the itching anymore. And you’d think that’s really not a reason to stop, but it is if you can’t control the patient’s itching without having them on corticosteroids.

Transcript edited for clarity.