[Induction chemotherapy for solid tumors]

Surgical treatment for solid malignancies, which is the gold standard for operable tumors, is being combined with nonsurgical modalities with an increasing frequency. Advanced cancers that are not curable by surgery alone are subjected to sophisticated multimodality regimens. Accordingly, the sequence and timing of integrated combined treatment modalities are essential. Traditionally, the common objective of induction chemotherapy has been to reduce the risk of distant disease recurrence. Administration of chemotherapy before other treatment has many theoretical advantages. Induction chemotherapy can result in tumor downstaging, thus increasing the rate of conservative surgery. In cases of more advanced disease, induction chemotherapy can render inoperable tumors resectable. Other advantages of induction chemotherapy include the ability to obtain information about tumor response, which can be used to study the biologic effects of chemotherapy and assess long-term disease-free survival(DFS)and overall survival(OS). Induction chemotherapy as a component of primary treatment has been shown in several studies and meta-analyses to decrease the incidence of metastatic disease. Currently, the terms induction, primary, preoperative, basal and neoadjuvant are all used to describe chemotherapy given as initial treatment. There are 2 methods of induction chemotherapy: intra-arterial induction chemotherapy and induction systemic chemotherapy. The clinical results of several trials of arterial infusion chemotherapy alone as induction chemotherapy for advanced cancer revealed that 20-30% higher response rates can be achieved. However, the benefits of prolonged survival rates and improved quality of life are not consistently realized. Induction arterial infusion chemotherapy did not gain enthusiastic support for several different malignancies. Induction systemic chemotherapy is mainly used in patients with stage II/III disease to improve surgical outcomes and increase the rate of breast-conserving surgery in the breast cancer case, although clinical studies have not revealed a significant improvement in DFS or OS. The favorable response rate and achievement of pathological complete response(pCR)have favorable effects on DFS in breast cancer patients. The available data suggest a minimal benefit for additional chemotherapy after surgery in patients with residual disease. New targets must be identified to develop non-cross-resistant agents for patients with residual disease after prior chemotherapy. New genomic and proteomic tools must be developed to identify predictive markers for response to primary systemic therapy that allow clinicians to develop more personalized therapy, new strategic options, and new biologic agents and avoid unnecessary regimens. The side effects of induction chemotherapy depend on the types of drugs, their doses, and the duration of treatment.