The CancerWeb Report, What's New In Cancer: July, 1996
Cervical Cancer

• A reason for poor response to radiotherapy? - Cancer of the uterine cervix in early stages is a highly-curable tumor, with radiation therapy giving five-year survival rates for Stage I disease in excess of 95%, comparable to or better than surgery. At later stages it is much more difficult to treat, which makes it essential to deliver the most effective therapy as soon as the tumor is diagnosed. Indicators of potential response to radiation therapy may be helpful in showing which patients have a poorer prognosis. Japanese researchers at Osaka University studied 52 patients with invasive cervix cancer (squamous cell), by measuring a number of potential indicators of sensitivity and response in tissue slides. They found that 48% of the patients had tumors that were positive for an enzyme called manganese superoxide dismutase (Mn-SOD). The five-year survival rates after a combination of external beam and locally-applied radiotherapy were 42.5% for those with the enzyme compared with 77% for those who lacked it. Those patients expressing the enzyme in their tumor specimens also showed a higher incidence of local tumor recurrence. Other potential genetic markers, p53 and c-erb-2, also were good indicators of poor prognosis, with comparable differences between survival of patients with positive and negative slides. (Nakano, Cancer Res 56:2771, 1996) Editor's Comment: - Mn-SOD is an enzyme that is able to destroy the reactive free radicals produced by radiation when it enters tumors, and which are responsible for damage to cells; this enzyme action will reduce the effectiveness of the radiation. It might be a useful prognostic indicator of response to radiation, independent of c-erb-2, helping to guide patient management in the direction of the most effective treatment.

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