AUSTIN, Texas — The anatomic location of a cutaneous squamous cell carcinoma (cSCC) tumor can be a clue to the risk for a poor outcome, such as metastasis or local recurrence, according to research presented at the American College of Mohs Surgery (ACMS) Annual Meeting 2026.

“Once we adjusted for confounding variables, we saw that the temple and lip are higher risk sites,” particularly local recurrence for the temple and nodal metastasis for the lip, Emma Merquetegui Lucke, BS, a second-year medical student at the Ohio State University, Columbus, Ohio, told attendees.

“The temple and the lip may require closer surveillance and escalation of treatment,” she said. “The trunk and extremity tumors are lower risk overall,” and though the scalp had “the highest incidence of poor outcomes, it was not found to be an independent predictor once we adjusted for confounding variables,” Lucke said.

Past studies have suggested that anatomic location may affect the outcomes of cSCC, with an increased risk for metastasis linked particularly to the temple, ear, and lip. Data on the association of tumor location and outcomes rely primarily on single-center cohort studies, however, which have limited power and external validity.

The researchers therefore aimed to assess whether anatomic location was an independent predictor of poor outcomes in cSCC based on data from a large, multicenter, multinational database.

They conducted a retrospective cohort study of 12 centers across the US, Spain, and Brazil. They categorized site locations for head and neck as scalp, temple, lip, ear, or other head and neck. Site locations for extremities were determined to be arms/legs or hands/feet, and the final site was the trunk.

The poor outcomes the researchers tracked included local recurrence, metastasis, disease-specific death, any poor outcome (the previous three combined), and major poor outcomes (death and metastasis). Their population of 11,506 patients included 19,046 tumors. The patients were a median of 74 years old, and 60% were men. They followed for a median of 35.9 months.

The locations with the highest percentages of poor outcomes were the scalp (6.6% of patients, temple (6.4%), and lip (4.8%). The proportions of poor outcomes were 4.5% for other head and neck locations, 3.6% for the ear, and 3% for the hands/feet. The two locations with the lowest proportions of poor outcomes were the trunk (2.4%) and the arms/legs (2%).

After adjustments for age, sex, Brigham and Women’s Hospital stage, immunosuppression, and treatment, tumors occurring on the temple had a 60% higher likelihood of local recurrence (subdistribution hazard ratio [SHR] 1.6, P = .01) and a 40% higher risk for any poor outcome (P = .028). However, the risk for nodal metastasis and disease-specific death were not statistically different for tumors on the temples compared to others.

Tumors on the lip had over twice the risk for nodal metastasis (SHR, 2.4; P = .006) and major poor outcomes (SHR, 2.3; P = .003), with no significantly different risks for local recurrence or disease-specific death.

Meanwhile, risks for poor outcomes were significantly lower for tumors on the trunk and extremities. Tumors on the trunk had a 60% reduced risk for local recurrence and a 50% lower risk for any poor outcome compared with tumors on the head and neck (P < .001).

Tumors on the arms and legs had also half the risk for any poor outcome compared with head/neck tumors (P < .001) and a 50%-80% reduced risk for all other outcomes studied (P < .001 except P = .016 for disease-specific death). Hand/feet tumors had significantly lower risks for all poor outcomes studied except disease-specific death, where risk was lower but not statistically significant.

The researchers did not find tumors on the scalp or ear to carry statistically greater or lesser risks for any poor outcomes. The research was limited by its retrospective design, classification bias, and the potential for data heterogeneity, Lucke said.

Joanna Walker, MD, associate professor of clinical dermatology at the University of Pennsylvania, and director of the Rare and Advanced Skin Cancer Clinic at the Penn Dermatology Oncology Center, Philadelphia, told Medscape Medical News that these findings were both surprising and helpful because they differ from what literature in the field has suggested.

“Classically, we’re told that some other sites are high risk, such as the ear, so the fact that they narrowed it down to the independently associated high-risk sites being the temple and the lip was super helpful,” Walker said. “It makes me wonder if some of that’s because anatomically, those are more complex, higher-stake surgical sites.”

She also wondered whether clearance of tumors at those locations is tougher, such as in the temple, “where you’re at risk for damaging the facial nerve branch,” she said.

“We’re always using what staging systems we have to prognosticate, but we are also always aware that there are other high-risk factors to add to that in our clinical decision making,” Walker said. Therefore, she added, “in thinking about the patients who might need to be monitored most closely after treatment, I think those sites are important to keep in mind in analyzing our high-risk patients.”

The research was funded by an American College of Mohs Surgery research grant. Lucke had no disclosures. Walker reported consulting for Sun Pharma.

Tara Haelle is a science/health journalist based in Dallas.