trastuzumab, paclitaxel, docetaxel, cyclophosphamide, fluorouracil, and methotrexate) and radiotherapy, especially after lumpectomy, and hormonal therapy (tamoxifen, letrozole). Adjuvant therapy in breast cancer is used in stage one and two breast cancer following lumpectomy, and in stage three breast cancer due to lymph node involvement. In glioblastoma multiforme, adjuvant chemoradiotherapy is critical in the case of a completely removed tumor, as with no other therapy, recurrence occurs in 1–3 months. In early stage one small cell lung carcinoma, adjuvant chemotherapy with gemcitabine, cisplatin, paclitaxel, docetaxel, and other chemotherapeutic agents, and adjuvant radiotherapy is administered to either the lung, to prevent a local recurrence, or the brain to prevent metastases. In testicular cancer, adjuvant either radiotherapy or chemotherapy may be used following orchidectomy. Previously, mainly radiotherapy was used, as a full course of cytotoxic chemotherapy produced far more side effects then a course of external beam radiotherapy (EBRT). However, it has been found a single dose of carboplatin is as effective as EBRT in stage II testicular cancer, with only mild side effects (transient myelosuppressive action vs severe and prolonged myelosuppressive neutropenic illness in normal chemotherapy, and much less vomiting, diarrhea, mucositis, and no alopecia in 90% of cases. Adjuvant therapy is particularly effective in certain types of cancer, including colorectal carcinoma, lung cancer, and medulloblastoma. In completely resected medulloblastoma, 5-year survival rate is 85% if adjuvant chemotherapy and/or craniospinal irradiation is performed, and just 10% if no adjuvant chemotherapy or craniospinal irradiation is used. Prophylactic cranial irradiation for acute lymphoblastic leukemia (ALL) is technically adjuvant, and most experts agree that cranial irradiation decreases risk of central nervous system (CNS) relapse in ALL and possibly acute myeloid leukemia (AML), but it can cause severe side effects, and adjuvant intrathecal methotrexate and hydrocortisone may be just as effective as cranial irradiation, without severe late effects, such as developmental disability, dementia, and increased risk for second malignancy. Dose-Dense Chemotherapy Dose-dense chemotherapy (DDC) has recently emerged as an effective method of adjuvant chemotherapy administration. DDC uses the Gompertz curve to explain tumor cell growth after initial surgery removes most of the tumor mass. Cancer cells that are left over after a surgery are typically rapidly dividing cells, leaving them the most vulnerable to chemotherapy. Standard chemotherapy regimens are usually administered every 3 weeks to allow normal cells time to recover. This practice has led scientists to the hypothesis that the recurrence of cancer after surgery