Increase in the average payment for adjuvant treatments and an increase in the percentage of cancer patients treated with chemotherapy. In the mid-to-late 1990s, the use of new and expensive agents, administered alone or in combination with existing agents showed superior survival benefits compared with prior approaches. However, the costs of these agents can be substantial. Given that many of the new and expensive targeted therapies are combined with existing therapies, they may add to rather than substitute for adjuvant therapy costs. Therefore, these new agents may be a large contributor to the rapidly escalating costs of cancer care. Another contributing factor in the rising costs of chemotherapy is the increased use of erythropoiesis-stimulating agents and granulocyte colony-stimulating factor. However, the costs of erythropoiesisstimulating agents and G-CSF may be justifiable if they enable the patient to maintain the treatment schedule. A limitation of studies use diagnostic or procedure codes from reimbursement claims to identify patients with incident disease is that they identify prevalent cases, over-identify cases from rule-out diagnostic procedures, and under-identify patients who have not received specific procedures or treatments due to insufficiently detailed coding. The diagnostic codes might also reflect metastatic rather than primary tumor sites. The phase-of-care approach classifies cancer patients according to the time of diagnosis and survival time. However, this classification was often problematic in the studies reviewed here. Another concern is the limitations of the method used to analyze and report cost data, such as methods for addressing censored or missing data and skewed distributions of cost data. Although other studies have proposed GDC-0879 standards for conducting and reporting cost-effectiveness analyses, no studies have proposed standards for conducting and reporting cost analyses. This issue merits further attention in future studies. In addition to exclusion of the most recently introduced chemotherapy agents, other limitations of this study are noted. For patients identified as undergoing cancer-directed surgery, the NHI procedures reported on the claims forms could have been miscoded. However, previous analyses of NHI data for specific surgical procedures agree that NHI data tend to be highly accurate and reliable. Moreover, this study did not include cancer stage, which is an important consideration in the choice of initial treatment, because cancer stage was not included in the NHI database. The cost estimates in this study are incomplete in several ways. Some patients did not receive cancer-related treatment according to the NHI data. The percentage of these patients varied by cancer site, which may explain why patients who presented with advanced disease did not undergo curative care. Many patients who did not receive cancer-directed treatment were hospitalized throughout the year. Therefore, their treatment costs would have been captured in the “other treatment” category.