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Emerging Role of EGFR-Targeted Therapies and Radiation in Head and Neck Cancer

The treatment of head and neck cancer has been at the forefront ofnovel therapeutic paradigms. The introduction of drugs that interactwith selective biologic pathways in the cancer cell has generated considerableattention recently. A wide variety of new compounds that attemptto target growth-signaling pathways have been introduced intothe clinic. A majority of studies in the clinic have focused on epidermalgrowth factor receptor (EGFR) antagonists, but future studies will likelybuild upon or complement this strategy with agents that target angiogenicor cell-cycle pathways. EGFR activation promotes a multitude ofimportant signaling pathways associated with cancer development andprogression, and importantly, resistance to radiation. Since radiationtherapy plays an integral role in managing head and neck squamouscell cancer (HNSCC), inhibiting the EGFR pathway might improveour efforts at cancer cure. The challenge now is to understand whenthe application of these EGFR inhibitors is relevant to an individualpatient and how or when these drugs should be combined with radiationor chemotherapy. Are there molecular markers available to determinewho will respond to EGFR inhibitors and who should be treatedwith alternative approaches? What are the mechanisms behind intrinsicor acquired resistance to targeted agents, and how do we preventthis problem? We need to formulate integrated laboratory/clinicalresearch programs that address these important issues.

Latest Article

Contemporary Management of Prostate Cancer With Lethal Potential

Screening for prostate cancer by determining serum prostate-specificantigen (PSA) levels has resulted in a stage migration such thatpatients with high-risk disease are more likely to be candidates for curativelocal therapy. By combining serum PSA, clinical stage, and biopsyinformation-both Gleason score and volume of tumor in the biopsycores-specimen pathologic stage and patient biochemical disease-freesurvival can be estimated. This information can help patients and cliniciansunderstand the severity of disease and the need for multimodaltherapy, often in the context of a clinical trial. While the mainstays oftreatment for local disease control are radical prostatectomy and radiationtherapy, systemic therapy must be considered as well. A randomizedtrial has shown a survival benefit for radical prostatectomy inpatients with positive lymph nodes who undergo immediate adjuvantandrogen deprivation. Clinical trials are needed to clarify whether adjuvantradiation therapy after surgery confers a survival benefit. PSAis a sensitive marker for follow-up after local treatment and has proventhat conventional external-beam irradiation alone is inadequate treatmentfor high-risk disease. Fortunately, the technology of radiationdelivery has been dramatically improved with tools such as three-dimensionalconformal radiation, intensity-modulated radiation therapy,and high-dose-rate brachytherapy. The further contributions of pelvicirradiation and neoadjuvant, concurrent, and adjuvant androgen deprivationtherapy have been defined in clinical trials. Future managementof high-risk prostate cancer may be expanded by clinical trialsevaluating neoadjuvant and/or adjuvant chemotherapy in combinationwith androgen deprivation.

Latest Article

New and Newer Vascular Targets in Oncology

This review covers progress to date in the identification of molecular targets on blood vessels in cancers, as well as agents that act on those targets, with emphasis on those currently in clinical trials. Current vascular-targeting therapies comprise two general types—antiangiogenic therapy and antivascular therapy. Advances in antiangiogenic therapies, particularly inhibitors of vascular endothelial growth factors and their receptors, have clarified the capacity of these inhibitors to change tumor-associated vessel structure to a more normal state, thereby improving the ability of chemotherapeutics to access the tumors. The responses of other antiangiogenesis target molecules in humans are more complicated; for example, αvβ3 integrins are known to stimulate as well as inhibit angiogenesis, and cleavage of various extracellular proteins/proteoglycans by matrix metalloproteinases produces potent regulators of the angiogenic process. Antivascular therapies disrupt established blood vessels in solid tumors and often involve the use of ligand-based or small-molecule agents. Ligand-based agents, irrespective of the antiangiogenic capacity of the ligand, target antivascular effectors to molecules expressed specifically on blood vessels, such as aminopeptidase N, fibronectin extra-domain B, and prostate-specific membrane antigen. Small-molecule antivascular agents, which are not targeted to molecules on blood vessels, rely on physical differences between the vasculatures in tumors and those in normal tissues.