Cutaneous Oncology Update: Dr. Ruiz

Emily Ruiz, MD:
There's a lot going on in the field of non-melanoma skin cancer. This is a broad field that covers a number of different malignancies, from cutaneous squamous cell carcinoma to basal cell carcinoma, to merkel cell and cutaneous sarcomas. There are a number of highlights in each field, and I selected 10 to talk about. For basal cell carcinoma, I focused on updates in metastatic basal cell. This is a really rare diagnosis with little information known about the disease.

But this past year, we published two studies looking at patterns of metastases and outcomes. Interestingly, for metastatic basal cell, it has a propensity to spread to the bone and lungs, which is a little bit unlike cutaneous squamous cell carcinoma, which often will just develop local regional disease in the draining nodal basin. But basal cell can actually skip that and just spread to the lung and bones.

For merkel cell carcinoma, I had the opportunity to share data from my colleagues at Brigham and Women's Hospital, Dana-Farber Cancer Institute on utilization of circulating tumor DNA, which is a liquid biomarker. This works really well in merkel cell carcinoma and is being routinely used in clinical practice. For cutaneous squamous cell carcinoma, there's a lot going on.

The treatment paradigm is really shifting. And for resectable disease, we are still performing surgery. But now we have new treatments in the neoadjuvant space, which is before surgery, and the adjuvant space, which is after surgery. For neoadjuvant immunotherapy, in the clinical trials, we're seeing over a 60% major pathologic response or pathologic complete response, and this has been shown to translate to better outcomes in follow-up.

Hot off the press is a press release on adjuvant cemiplimab going over a 60% reduction in adjuvant immunotherapy after radiation compared to placebo. And so we'll continue to see the paradigms evolve for cutaneous squamous cell carcinoma. Finally, I had the opportunity to share data about multidisciplinary care, which has been shown in other cancers to save lives. And this is really important because working with our colleagues is essential.

In a separate session, I presented a late-breaking abstract looking at the 40-GEP tests from Castle Biosciences in head and neck cutaneous squamous cell carcinomas. This test has been evaluated in cutaneous squamous cell carcinomas from different regions of the body. But we actually see that the majority of deaths from cutaneous squamous cell carcinoma arise from tumors from the head and neck.

And so we look to see how the test performed in this population alone. Looking at over 800 cutaneous squamous cell carcinomas, we saw that the GEP did a really nice job at risk stratifying the tumors, with the class 1 tumors having over a 90% three-year metastasis-free survival, class 2A having about an 80% metastasis-free survival, and class 2B having less than 60% metastasis-free survival.

So this will be really helpful in clinical practice, and we've shown in other studies how we can use the 40-GEP tests to guide both radiologic imaging and adjuvant radiation.