PREVENTION OF MANIFEST METASTASIS WITH MONOCLONAL-ANTIBODIES - A NOVEL-APPROACH TO IMMUNOTHERAPY OF SOLID TUMORS

Until now, surgery, chemotherapy and radiotherapy have remained the mainstay of current cancer therapy. The major limitation of chemo- and radiotherapy is their narrow therapeutic index between cancer and normal cells. In the search for less toxic and more specific therapies, various modalities of immunotherapy have been tried. It is now increasingly recognised that patients presenting with minimal cancer burden or micrometastatic disease will experience the greatest benefit from treatment with monoclonal antibodies (mAbs). The first proof of efficacy of a monoclonal antibody in minimal residual disease has recently been published, with mAb 17-1A in patients with colorectal cancer stage III after complete resection of the primary tumour. After a median follow-up of 5 years, antibody therapy reduced the overall death rate by 30% and decreased the recurrence rate by 27%. This result is similar to the benefit obtained in (radio)chemotherapy trials, however, with notably lesser toxicity. It is clear from past experience that all currently available treatment modalities for cancer are far from perfect. However, because the mechanism of action or target cells of different treatment modalities may be complementary in the control of tumour growth, the next logical step is to rationally design clinical trials that combine conventional chemo-, hormonal or radiation therapy with immuno- or biotherapy.