Metformin as an Alternative Radiosensitizing Agent to 5-Fluorouracil During Neoadjuvant Treatment for Rectal Cancer.

BACKGROUND: Neoadjuvant chemoradiation for locally advanced rectal cancer combining 5-fluorouracil with radiation increases tumor regression compared with radiation alone. However, it occurs at the cost of significant treatment-related toxicity. Patients with rectal cancer using metformin have been associated with improved response to radiotherapy. OBJECTIVE: The purpose of this study was to evaluate the radiosensitizing effects of metformin in vitro and in vivo and compare it with a standard combination of radiation/5-fluorouracil. DESIGN: Colorectal cancer cell lines SW480, HT29, and HCT116 were used as models. Cell viability was compared under treatments with radiation, radiation/5-fluorouracil, metformin, radiation/metformin, and radiation/5-fluorouracil/metformin. Nude mice were injected subcutaneously with SW480 cells and treated for 1 week with radiation/5-fluorouracil, metformin, radiation/metformin, or radiation/5-fluorouracil/metformin. Tumor volume was evaluated for 4 weeks after treatment completion. The phosphorylation status of key proteins of the PI3K/Akt/mTOR pathway was determined by immunoblots. SETTINGS: This was an experimental study conducted in vitro and in vivo. PATIENTS: Animal models/cell lines were used. MAIN OUTCOME MEASURES: The end point was to investigate how metformin compares with 5-fluorouracil as a radiosensitizer. RESULTS: All cell lines significantly decreased cell viability after treatment with radiation/metformin when compared with radiation alone. Radiation/metformin was superior to radiation/5-fluorouracil in SW480 (37% vs 74%; p < 0.001). In HT29 and in HCT116, radiation/metformin was inferior to radiation/5-fluorouracil (40.0% vs 13.8%, p < 0.001 and 40.0% vs 7.0%, p < 0.001), mainly because of increased 5-fluorouracil toxicity (≤20% of cell viability). In vivo assays indicated that radiation/metformin treatment was comparable with radiation/5-fluorouracil (557 vs 398 mm; p > 0.05) and that the addition of metformin to the standard radiation/5-fluorouracil did not improve tumor response (349 mm; p > 0.05). Metformin exerted strong PI3K/Akt/mTOR pathway inactivation effects after 24-hour exposure (increasing pAMPK, p < 0.01; decreasing pAkt, p < 0.01; and pS6, p <0.05). LIMITATIONS: In vitro and in vivo chemoradiation regimens cannot be directly translated to human delivery methods. CONCLUSIONS: Metformin enhances tumor response to radiation in vitro and in vivo. Metformin is an attractive alternative radiosensitizing agent to be considered in future studies/trials. See Video Abstract at http://links.lww.com/DCR/B219. LA METFORMINA COMO AGENTE RADIOSENSIBILIZADOR ALTERNATIVO A 5FU DURANTE EL TRATAMIENTO NEOADYUVANTE PARA CÁNCER DE RECTO: La quimiorradiación neoadyuvante para el cáncer de recto localmente avanzado que combina 5FU con radiación aumenta la regresión tumoral en comparación con la radiación sola. Sin embargo, se produce a costa de una toxicidad significativa relacionada con el tratamiento. Los pacientes con cáncer de recto que usan metformina se han asociado con una mejor respuesta a la radioterapia.Evaluar los efectos radiosensibilizantes de metformina in vitro e in vivo y compararlo con la combinación estándar de radiación / 5FU.Se usaron como modelos las líneas celulares de cáncer colorrectal SW480, HT29 y HCT116. La viabilidad celular se comparó en tratamientos con radiación, radiación / 5FU, metformina, radiación / metformina y radiación / 5FU / metformina. A los ratones desnudos se les inyectó por vía subcutánea células SW480 y fueron tratados durante una semana con radiación / 5FU, metformina, radiación / metformina o radiación / 5FU / metformina. El volumen tumoral se evaluó durante 4 semanas después de la finalización del tratamiento. El estado de fosforilación de las proteínas clave de la vía PI3K / Akt / mTOR se determinó mediante inmunotransferencias.Estudio experimental in vitro e in vivo.Modelo animal / líneas celulares.El punto final fue investigar cómo la metformina se compara con 5FU como un radiosensibilizador.Todas las líneas celulares disminuyeron significativamente la viabilidad celular después del tratamiento con radiación / metformina en comparación con la radiación sola. La radiación / metformina fue superior a la radiación / 5FU en SW480 (37% frente a 74%; p <0,001). En el HT29 y el HCT116 la radiación / metformina fue inferior a la radiación / 5FU (40% vs 13.8%, p <0.001 y 40% vs 7%, p <0.001; respectivamente), debido principalmente al aumento de la toxicidad de 5FU (≤20% de la célula viabilidad). Los ensayos in vivo indicaron que el tratamiento con radiación / metformina era comparable a la radiación / 5FU (557 vs 398 mm, p > 0.05), y que la adición de metformina a la radiación estándar / 5FU no mejoró la respuesta tumoral (349 mm, p > 0.05). La metformina ejerció fuertes efectos de inactivación de la vía PI3K / Akt / mTOR después de 24 horas de exposición (aumentando pAMPK p < 0.01, disminuyendo pAkt, p < 0.01; y pS6, p < 0.05).Los regímenes de CRT in vitro e in vivo no se pueden traducir directamente a los métodos de entrega en humanos.La metformina mejora la respuesta tumoral a la radiación in vitro e in vivo. La metformina es un agente alternativo de radiosensibilización atractivo para ser considerado en futuros estudios / ensayos. Consulte Video Resumen en http://links.lww.com/DCR/B219. (Traducción-Dr Gonzalo Hagerman).

Adjuvant and neoadjuvant cancer therapies: A historical review and a rational approach to understand outcomes.

Drug development in oncology usually establishes efficacy in metastatic disease before advancing a therapy to the adjuvant or neoadjuvant settings. Unfortunately, too often use in adjuvant or neoadjuvant settings fails to improve overall survival. Reasons for the modest benefits include the fact that in many cases surgery cures a majority of patients making it difficult to demonstrate gains. We begin by looking at the history of adjuvant and neoadjuvant therapies and the principles guiding their development. We summarize accepted adjuvant and neoadjuvant therapies in several cancers and tabulate their outcomes. Then, extending our work on the growth and regression rate constants of tumors and the fraction of cells killed we demonstrate that therapies developed in the metastatic setting primarily delay tumor growth rather than kill more cells and argue this is a likely explanation for poor outcomes in adjuvant or neoadjuvant settings. We suggest a rational approach for enhancing success.

Treatment of malignant pleural mesothelioma with chemotherapy preceding versus after surgical resection.

OBJECTIVES: There are 2 main treatment paradigms recognized by the National Comprehensive Cancer Network for resectable malignant pleural mesothelioma (MPM): induction chemotherapy followed by resection (IC/R), and up-front resection with postoperative chemotherapy (R/PC). These paradigms are being compared in an accruing randomized phase II trial. In the absence of such completed trials, in this study we evaluated overall survival (OS) and postoperative outcomes of IC/R and R/PC. METHODS: The National Cancer Database was queried for newly diagnosed epithelioid/biphasic MPM. Metastatic, node-positive, and/or cT4 disease was excluded, along with nondefinitive surgery and lack of chemotherapy. Multivariable logistic regression ascertained factors independently associated with induction chemotherapy delivery. Kaplan-Meier analysis was used to evaluate OS between cohorts; multivariable Cox proportional hazards modeling was used to assess factors associated with OS. Survival was also evaluated between propensity-matched populations. Last, postoperative outcomes were assessed between groups. RESULTS: Overall, 361 patients (182 IC/R, 179 R/PC) were analyzed. Temporal trends revealed that IC/R is decreasing over time. Survival of the IC/R cohort was similar to that of R/PC patients (20.9 vs 21.7 months; P = .500); this persisted after propensity matching (20.8 vs 22.0 months; P = .270). However, patients who underwent IC/R experienced longer postoperative hospitalization (median 7 days vs 6 days; P = .001) and higher 30-day mortality (3.3% vs 0%; P = .020). CONCLUSIONS: To our knowledge, this is the only comparative investigation of the 2 major management paradigms of operable MPM. IC/R regimens are decreasing over time in the United States. Although associated with survival similar to R/PC, IC/R might be associated with worse postoperative outcomes. Careful induction chemotherapy patient selection is thus highly recommended.

Neoadjuvant therapy for melanoma: a promising therapeutic approach and an ideal platform in drug development.

Patients with locoregionally advanced but surgically operable melanoma continue to carry a high risk of relapse and death despite the best available standard management approaches. Neoadjuvant studies targeting this patient population tested chemotherapy with temozolomide and biochemotherapy (BCT), in which BCT demonstrated high tumor response rates but was eventually abandoned with the failure of BCT to deliver survival benefits in randomized trials of metastatic disease. Smaller neoadjuvant immunotherapy studies with interferon (IFN) alfa and ipilimumab have yielded promising clinical activity and important mechanistic insights and biomarker findings. Newer targeted and immunotherapeutic agents and combinations currently are being translated into the neoadjuvant setting at an accelerated pace and carry significant clinical promise. In drug development, the neoadjuvant approach allows access to blood and tumor tissue before and after initiation of systemic therapy, which allows for the conduct of novel mechanistic and biomarker studies in the circulation and the tumor microenvironment. Such studies may guide drug development and allow for the discovery of predictive biomarkers selected on the basis of their capacity to classify patients according to the degree of benefit from treatment or the risk for significant toxicity.

Quimioterapia em câncer de mama / Chemotherapy for breast cancer

Em 2010, um milhão e meio de mulheres receberão o diagnóstico de câncer de mama no mundo, sendo 49.000 no Brasil. O câncer de mama e uma área em constante evolução, exigindo, tanto da parte de mastologistas quanto dos oncologistas, rápida adaptação aos novos conceitos. Sabe-se que o câncer de mama não e uma doença única e, portanto, seu tratamento deve ser individualizado. A quimioterapia é uma parte importante do tratamento desta doença e tem evoluído recentemente, juntamente com a cirurgia, hormonioterapia, radioterapia e outros tratamentos de suporte, fazendo com que a mortalidade por esta doença continue a diminuir. Baseado em dados dos estudos de perfil molecular, e possível que mais de 50% das pacientes recebam quimioterapia adjuvante desnecessariamente. Revisa-se aqui o papel dos novos testes de perfil molecular disponíveis e o estado atual do uso de quimioterapia no câncer de mama. Nesta revisão, e dado especial enfoque ao tratamento adjuvante e neoadjuvante, sendo descritas algumas particularidades como o tratamento das pacientes idosas, da doença HER-2 positiva e da doença metastática.

In 2010, one and a half million women will be diagnosed with breast cancer worldwide, and 49, 000 in Brazil. Breast cancer is a constantly evolving area requiring from Mastologists and Oncologists a fast adaptation to new concepts. Furthermore, breast cancer does not consist of a single entity, therefore, it requires individualized treatment approaches. Chemotherapy is an important treatment modality, and it has been a rapidly evolving area that has been contributing to the decreasing breast cancer mortality observed in recent years, along with surgery, hormone therapy, radiotherapy, and other supportive treatments. Based on data from molecular profiling studies, more than 50% of the patients may be receiving unnecessary adjuvant chemotherapy. We aim to review the role of new molecular profiling tests and the current state of art in chemotherapy treatment for breast cancer. We also address the important issue of chemotherapy treatment in elderly patients, and the management of HER -2 positive and metastatic disease.