Cetuximab plus radiotherapy may be an effective treatment option for locally advanced cutaneous squamous cell cancers (laCSCC), with manageable toxicity, according to a study in Oncotarget.

Cetuximab is an epidermal growth factor receptor (EGFR) inhibitor with the following US Food and Drug Administration-approved indications: colorectal cancer, metastatic, KRAS wild-type (without mutation), and head and neck cancer. 

Researchers Mark Chang, Wolfram Samlowski and Raul Meoz from University Medical Center of Southern Nevada, Comprehensive Cancer Centers of Nevada, University of Nevada Las Vegas, and University of Nevada Reno conducted a retrospective review of institutional data and identified 18 patients with laCSCC treated with cetuximab induction and concurrent radiotherapy.  The loading dose of cetuximab was 400 mg/m² IV. Subsequent weekly doses of 250 mg/m² IV were infused throughout the period of radiation. The treatment doses ranged from 4500–7000 cGy, with a dose fraction of 200-250 cGy. The objective response rate was 83.2% with 55.5% complete responses and 27.7% partial responses. 

Median progression-free survival was 21.6 months. Progression-free survival was 61% at 1 year and 40% at two years, the new study showed.  With longer follow-up, some patients developed a local recurrence (16.7%), distant metastases (11.1%) or a second primary cancer (16.3%). Cetuximab was well tolerated, with 68.4% patients experienced only mild acneiform skin rash or fatigue (Grade 1 or 2). Radiotherapy produced expected side effects (skin erythema, moist desquamation, mucositis).

“Cetuximab plus radiotherapy represents an active and tolerable treatment option for laCSCC, including patients with contraindications for checkpoint inhibitor therapy,” the researchers concluded.

PHOTO CAPTION: Figure 1: Example of treatment response.

PHOTO CREDIT: 2023 Chang et al.