Low levels of a specific protein are associated with particularly good results of radiotherapy in women with early-stage breast cancer, a new Swedish study has shown.
Writing in Clinical Cancer Research, the researchers at Karolinska Institutet and Gothenburg University, Sweden, add that the efficacy of radiotherapy can be improved with drugs that block the PDGFRb protein.
Standard treatment for DCIS (ductal carcinoma in situ) is surgery and subsequent radiotherapy, and although the prognosis is generally good, about 10% of patients suffer a recurrence within ten years of diagnosis.
Fredrik Wärnberg, professor at the Department of Clinical Sciences at Gothenburg University’s Sahlgrenska Academy, said: “It is well-known that the benefits of radiotherapy are individual, so we need to find predictive markers that can be used to avoid unnecessary or ineffective radiotherapy.”
Previous studies have focused mainly on markers in the tumour cells, but recent findings have found that supporting tissue around the tumour cells can affect the therapeutic effect of DCIS, while studies in cell and animal models found the efficacy of radiotherapy can be influenced by fibroblasts.
Arne �-stman’s research group at Karolinska Institutet and Professor Wärnberg’s group analysed a large tissue collection from SweDCIS, a randomised radiotherapy study and found low levels of PDGFRb, are associated with especially high radiotherapeutic efficacy for women with DCIS.
As a result, several new studies have been launched.
Study first author Carina Strell, researcher at the Department of Immunology, Genetics and Pathology, Uppsala University, and the Department of Oncology-Pathology, Karolinska Institutet, said: “The treatment guidelines of DCIS might need to be changed if these studies confirm our original findings.”
Strell C, Folkvaljon D, Holmberg E et al. High PDGFRb expression predicts resistance to radiotherapy in DCIS within the SweDCIS randomized trial. Clinical Cancer Research 5 May 2021; doi: 10.1158/1078-0432.CCR-20-4300.
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