Tumor staging update improves cSCC treatment

0809-Council

M. Laurin Council, MD

Cutaneous squamous cell carcinoma (cSCC) is the second-most common cancer in the United States, but its treatment has lagged behind that of other cancers because of the lack of solid data about the disease. That is changing with the development of an updated tumor staging system that identifies patients most at risk and treatments that are more effective for those patients.

The changes in tumor classification and treatment were explained through the review of cases July 29 during “Current Management of High-Risk Cutaneous Squamous Cell Carcinoma” (U010).

“Although the overwhelming majority of patients with cutaneous squamous cell carcinoma are cured with surgery alone, there are certain patients who go on to do poorly, developing metastases and ultimately dying of their disease. These patients need to be identified early in the course of their disease so we can manage them appropriately,” said the course director, M. Laurin Council, MD, assistant professor of dermatology at Washington University School of Medicine, St. Louis.

A key in identifying those patients has been subdividing the tumor staging system so the T2 classification is divided into T2a and T2b subgroups. The new system was pioneered at Brigham & Women’s Hospital, Boston, and many of its aspects will be included in the eighth edition of the American Joint Committee on Cancer (AJCC) staging system that will be published this fall.

“At Brigham & Women’s, we developed a staging system that subdivides that big T2 group into high-stage and low-stage groups,” said Chrysalyne D. Schmults, MD, MSCE, a course presenter. “The upper of the two stages comprises only 5 percent of squamous cell carcinomas, but 70 percent of the nodal metastases and 83 percent of deaths.

“We were able to categorize most of the patients who were going to end up having a poor outcome within the 5 percent group. This means that the staging system, which allows you to predict who is likely to do well and who is likely to do poorly, helps clinicians decide who needs lymph node staging and who might need adjuvant therapy beyond clear surgical margins.”

Dr. Schmults, associate professor of dermatology at Harvard Medical School, said the staging system has four risk factors for tumors:

  • Diameter of 2 cm or greater
  • Depth beyond the subcutaneous fat
  • Poor differentiation
  • Perineural invasion — invasion of the nerve sheath of large-caliber nerves, 0.1 mm or greater in diameter, by tumor cells

“Patients who have two to three of those risk factors are the group we are focusing on, as well as those patients who have four high-risk factors, which correspond to tumor stages T2b and T3,” said session speaker Desiree Ratner, MD.

“In those patients, even though we do aggressive surgery and obtain clear margins, we are concerned that their cancer may already have spread, so we think about adjunctive treatment,” said Dr. Ratner, professor of dermatology, Icahn School of Medicine at Mount Sinai, New York. If it is a tumor that appears to be in the T2b or T3 stage, we refer those patients for radiation. They may also receive cetuximab, which is an EGFR (epidermal growth factor receptor) antagonist.”

A multidisciplinary team approach is also key in treatment because distinct clinical guidelines for the management of higher risk squamous cell carcinomas have not been developed, as with other cancers, Dr. Council said.

“A lot of hospitals or universities will have tumor boards that are attended by radiation oncologists, medical oncologists, surgical oncologists, dermatologists, or otolaryngologists,” she said. “It is important that these cases be discussed among physicians from different disciplines to come up with a unique approach for each patient. There are emerging therapies that might be of benefit to some of these patients, so it is important to continue to keep up with the literature as our treatments are evolving.

“The idea behind the session is to come up with clinical guidelines, or suggestions for how care should be coordinated for these higher risk squamous cell carcinoma patients because we currently don’t have them.”

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