Radiation Therapy is Effective Treatment for Superficial Skin Cancer

Contact:
Darrell E. Ward
314.286.0122
wardd@msnotes.wustl.edu

Dec. 11, 2001 – A study at Washington University School of Medicine in St. Louis provides further proof that radiation therapy is a safe and effective treatment for the two most common forms of skin cancer, basal cell and squamous cell carcinoma.

"Our study shows that radiation therapy is a safe and effective treatment for superficial skin cancer, and that the cosmetic results are usually very good," says Jay E. Locke, M.D., associate radiation oncologist at Washington University's Mallinckrodt Institute of Radiology and the study's lead author.

More than 500,000 Americans develop skin cancer each year, says Locke. "Most cases of skin cancer are caused by prolonged sun exposure, usually when people are young, but skin cancer can develop any time of the year, and it is highly curable when detected and treated early.

The retrospective study, published in the November issue of the International Journal of Radiation Oncology, Biology, and Physics, looked at the outcome of 468 patients with a total of 531 skin tumors. All patients were treated with radiation therapy between January 1966 and December 1997. Of the tumors, 389 were basal cell carcinoma,142 were squamous cell carcinoma and 167 were recurrent malignancies. The great majority of basal cell carcinoma (361) and squamous cell carcinoma (118) tumors were on the face.

Patients with basal cell carcinoma ranged in age from 11 to 100 years, with an average age of 73; those with squamous cell carcinoma ranged in age from 32 to 97 years, with an average age of 72. The patients were followed for an average of 5.8 years.

The researchers found that 92 percent of the basal carcinoma tumors and 80 percent of the squamous cell carcinoma tumors remained under control (i.e., did not recur) during the follow-up period. Tumors treated after they had recurred following initial surgery had a lower control rate: 86 percent for basal cell carcinoma and 68 percent for squamous cell carcinoma. Treatment success was greatest--96 percent for squamous cell carcinoma and 100 percent for basal cell carcinoma--in previously untreated tumors less than half an inch (i.e., one centimeter or less) in diameter.

The researchers also measured cosmetic changes due to treatment. They looked for three kinds of skin changes: small patches of enlarged capillaries (telangectasia), a lightening or darkening of the skin, or abnormal thickening of the skin (skin fibrosis).

Patients with no changes were considered to have had an excellent cosmetic outcome; those with mild changes were judged as having a good outcome; and those with severe changes were considered as having a poor outcome.

Cosmetic data were available for 85 percent of the basal cell carcinoma cases and for 75 percent of the squamous cell carcinoma cases. Overall, 92 percent had excellent or good results. A good-to-poor outcome occurred more often in patients treated for squamous cell carcinoma (13 percent) than in those with basal cell carcinoma (5.9 percent). This was due to the higher doses of radiation needed for squamous cell carcinoma, which can progress deeper into the skin than basal cell carcinoma and even invade lymph nodes. Patients with recurrent squamous cell carcinoma also had a higher rate of good-to-poor outcome (18 percent) compared to recurrent basal cell carcinoma (1.8 percent).

Skin cancer is also treated using surgery, cryosurgery (use of cold), and curettage (scraping). Radiation therapy for skin cancer is usually more expensive than surgery, says Locke. "The real advantage to this radiation therapy is not its cost, but its outcome, which is excellent in terms of cosmetic results."

Side effects of radiation therapy are generally minor. Immediately after treatment, there may be skin redness and blistering similar to a mild sunburn. The affected area is small, however, because the tumors are small. These side effects clear up when treatment stops. Long-term side effects are the skin changes measured in the study: skin lightening or darkening, telangectasia, skin fibrosis.

"This study adds to the large body of experience showing that radiation therapy is an excellent choice for treating skin cancer when cosmetic outcome is important," says Locke. "But early detection is crucial. Everyone should have an annual physical examination and be aware of any changes in moles and of the appearance of any new spots."

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Locke J, Karimpour S, Young G, Lockett MA, Perez CA. Radiotherapy for epithelial skin cancer. International Journal of Radiation Oncology, Biology, and Physics, 51(3) 748-755, November 1, 2001.

The full-time and volunteer faculty of Washington University School of Medicine are the physicians and surgeons of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient-care institutions in the nation. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.
 
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