Do Keloids Convey a Higher Cancer Risk?

WASHINGTON — Keloids may be linked with human cancers among Asian populations, a researcher reported here.

In cohort study in Taiwan, patients with keloids were at an increased risk of developing various forms of cancer — pancreatic cancer and skin cancer in particular — when compared to the general population, with an adjusted odds ratio of 1.51 (95% CI 1.39-1.63), according to Kathy Chien-Hui Hong, MD, PhD, of National Yang-Ming University in Taipei, and colleagues.

When compared with non-keloid patients, keloid patients had a 1.73 times greater risk of developing skin cancer. Male patients had an even greater adjusted relative risk of 2.16 (95% CI 1.17-4.00), Hong reported at the American Academy of Dermatology meeting.

For pancreatic cancer, female patients with keloids were at an increased risk (adjusted RR 2.19, 95% CI 1.08-4.42), she added.

Previous reports have indicated that keloids occur as an abnormal wound heals, and they are more common in tension areas, like the back and chest, and among people with darker skin. Following injury or trauma, these non-cancerous fibrous proliferations appear in the dermis. Keloids tend to appear beyond the initial injury site unlike hypertrophic scars. A number of factors may be at play including cytokines, TGF-β, and other growth factors, Hong noted.

Similarities are found between cancers and keloids as they are proliferations and uncontrolled cell growths. A number of cancers come from sclerotic microenvironments including oral cancer, Majorlin’s cancer, and hepatoma, she explained. However, there are sporadic case reports in which patients developed keloids and some form of cancer, Hong added.

The researchers evaluated an Asian cohort of 17,401 patients with keloids and 69,604 in the comparative group. The participants were 61.9% female and had an overall mean age of 38.4.

Patients were excluded if they were less than age 20 years, were diagnosed by a clinician that was not a plastic surgeon or dermatologist, had a keloid diagnosed, or a cancer diagnosis before January 1998, or had “suspicions misclassified (sex-specific disease).”

The adjusted OR ratio for overall cancer risk among all patients with keloids was 1.51 (95% CI 1.39-1.63). Among all patients with keloids, the OR for specific cancer was:

• Pancreatic cancer: 2.57 (95% CI 1.59-4.18)
• Melanoma: 3.40 (95% CI 1.78-6.50)
• Skin cancer: 4.35 (3.16-5.99)
• Esophageal cancer: 1.70 (95% CI 1.06-2.71)
• Colon cancer: 1.54 (95% CI 1.28-1.86)
• Kidney Cancer: 1.77 (95% CI 1.03-3.03)
• Thyroid Cancer: 1.71 (95% CI 1.22-2.41)
• Hodgkin’s Lymphoma: 1.77 (95% CI 1.13-2.79)

The overall OR of prostate cancer among men was 1.63 (95% CI 1.14-2.32), and the overall OR of breast cancer among women was 1.28 (95% CI 1.03-1.58).

Further research is warranted as the association between cancer and keloids remains uncertain, Hong stated.

“Complete dermatological and physical checkup along with regular abdominal exam and appropriate imaging should be implemented in the medical care of patients with keloids,” she suggested.

The relationship between keloids and cancer “may sort of stimulate some more thought into how we can replicate these studies for different findings,” noted Hensin Tsao, MD, PhD, of Massachusetts General Hospital in Boston.

“I think the most critical thing is really the association that we are seeing now between a benign fibroproliferative tumor with other sorts of conditions, with other cancers internally and also on the skin,” Tsao, who was not involved in the study, told MedPage Today.

But “I am not sure based on the absolute numbers… whether there should be appropriate pancreatic screening for say patients with keloids,” he emphasized.