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Download WHAT’SUNDER YOUR SKIN? WHAT’S UNDER YOUR SKIN? Skin Care of Breast Cancer Patients Undergoing Standard External Beam Radiation Donna M. Braunreiter RN

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  • WHATSUNDER YOUR SKIN? WHATS UNDER YOUR SKIN? Skin Care of Breast Cancer Patients Undergoing Standard External Beam Radiation Donna M. Braunreiter RN BSN OCN MSN Student Alverno College Spring 2009, MSN 621 dmbraunreiter @ aol.com dmbraunreiter @ wi.rr.com
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  • Objectives 1.Explain effects of external beam radiation therapy. 2.Briefly describe genetic mechanisms involved in radiation. 3.Summarize the acute physiologic mechanisms of inflammation. 4.Describe the structure and function of skin. 5.Identify breast skin changes after radiation treatment. 6.Review nursing care for breast cancer patients undergoing radiation therapy.
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  • Directions To move to the next slide, click this To move to the previous slide, click this To return to the beginning, click this To return to the topics section, click this
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  • RADIATION Microsoft Office Clip Art 2007
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  • Radiation Treatment Skin reaction is the most common side effect during breast cancer radiation treatments Over 90% of women receiving radiation for breast cancer will develop some skin changes during their course of treatment
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  • Radiation Interacts with all biological materials in its path Direct and indirect damage to cells causes DNA changes Causes many molecular responses that induce cellular mechanisms for DNA repair, cell cycle arrests, and apoptosis
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  • Radiation Major effect on dividing cells is reproductive death Leaves cells unable to reproduce Radiosensitivity of cell determines degree of injury and when it will happen
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  • Radiation Direct Effect DNA absorbs radiation The atoms become ionized and damaged Less common than indirect damage Microsoft Office Clip Art 2007
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  • Radiation Indirect Effect Water molecules surrounding DNA are ionized Creates highly reactive free radicals such as hydroxyl radicals, peroxide, hydrated electrons, and oxygen radicals These radicals interfere with DNA and cause damage and strand breakage Common because 80% of a cell is water
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  • Radiation Damage Direct and indirect damage break bonds in DNA backbone Results in loss of base, nucleotide, or one or both strands of DNA Single-strand DNA breaks are repaired using the opposite strand as a template Can result in mutation if not repaired correctly
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  • Radiation Damage Double-strand DNA breaks related to cell killing Results in mitotic death X-rays are sparsely ionizing and cause locally clustered damage Leads to clinically significant events DNA Structure United States National Library of Medicine http://ghr.nlm.nih.gov/handbook/illustrations.dnastructure.jpg
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  • Radiation CONTROLS CANCER CELLS BY 1.Inducing apoptosis 2.Causing permanent cell cycle arrest or terminal differentiation 3.Inducing cells to die of mitotic catastrophe
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  • Apoptosis Programmed cell death Radiation damage triggers signaling cascades which causes cell self-destruct mechanisms Characteristics are nucleus fragmentation and blebbing Tumors undergoing apoptosis have good clinical response
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  • Cell Cycle www.wikigenetics.org/images/4/4b/Cell_cycle1.jpg
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  • Cell Cycle Death/Terminal Differentiation (Denucleation) Cells can arrest in any phase of cell cycle Radiation damage mainly in G1 and G2 phases Normal cells and cancer cells retaining p53 function block in G1 Cancer cells with p53 loss or mutation block in G2 phase G2 arrest related to cellular repair of DNA radiation-induced DNA damage
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  • Radiation Effects Radiosensitive Cells renewing rapidly with little or no differentiation Examples are skin cells, mucous membranes, and hematopoietic stem cells Radioresistant Cells that do not divide regularly or at all and are highly differentiated Examples are muscle cells and nerve cells
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  • Radiation Effects Radiosensitive Acute effects Damage within weeks to months of exposure Temporary Normal cells affected are capable of repair Dependent upon dose-time- volume factors Radioresistant Late effects Damage months or years after first exposure Permanent Damage becomes more severe as time goes on Dependent upon dose-time- volume factors
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  • Radiation Effects Radiosensitive Higher doses over shorter periods of time to larger volumes of tissues result in more severe acute reactions Acute damage results from depletion of actively proliferating parenchymal or stromal cells Characteristics are vascular dilation, local edema, and inflammation Radioresistant Severity of late effects more dependent upon total dose delivered and volume if tissue irradiated Damage to endothelial cells or connective tissues results in late effects occurring as a result of narrowing or occlusion of small vasculature and fibrosis
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  • Radiation Effects Acute and late side effects from radiation therapy are LOCAL and ONLY affect tissues receiving treatment Presence and severity of acute effects can not predict late effects of radiation Late reactions such as tissue necrosis or dense tissue fibrosis can occur independently of acute reactions
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  • SUPINE POSITION Most common position for breast cancer radiation therapy MUST be used if lymph nodes need to be treated May involve radiation exposure to heart, lungs, ribs, and contralateral breast Microsoft Office Clip Art 2007
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  • PRONE POSITION Used for women with larger pendulous breast, cardiac and/or pulmonary comorbidities Possible improved dose homogeneity Potential reduction in lung and heart irradiation Microsoft Office Clip Art 2007
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  • Patient-Related Considerations Normal age-related changes: thinning of the epidermis and dermis, diminished elasticity, decreased dermal turgor, which results in delayed healing. Nutritional status is also important for healing.
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  • What is the effect of radiation on cells? A. Reproductive death of cells throughout the body C. Radiation skin reactions cause internal injuries. D. Radiation helps repair DNA damage. B. Reproductive death of cells in the treated area only
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  • Wrong answer, try again. Radiation only affects the area being treated and causes damage to DNA. Click here to return to question
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  • Correct! Radiation causes the reproductive death of cells in the treated area only.
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  • GENETICS Microsoft Office Clip Art 2007
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  • Chromosome: rod-shaped molecule of DNA threaded around proteins containing specific genes that carry hereditary information Histones are proteins that act as spools around which DNA winds, as compaction is necessary to large genes inside cell nuclei; histones also function as gene regulators United States National Library of Medicine http://ghr.nlm.nih.gov/handbook/illustrations/chromosomestructure.jpg
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  • GENE: biological unit of hereditary; segment of DNA needed to contribute to a function and specifies a trait United States Library of Medicine http://ghr.nlm.nih.gov/handbook/illustrations/geneinchromosome.jpg
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  • Radiation effect on genes 1.Ionizing radiation causes phosphorylation of histone H2AX (forming gamma-H2AX) 2.Reaction dependent on ataxia telangiectesia mutated (ATM) molecule 3.Followed by accumulation of 53BP1, a protein acting as central mediator for critical pathways, including phosphorylating (which conveys the DNA damage signal to) tumor suppressor protein p53
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  • Genetics in Radiation 4.Next, phosphorylating the ATM protein amplifies the damage signal 5.And recruits proteins critical for repair, such as the BRCA1 and HDAC4 6.Which allows a G2 cycle checkpoint 7.53BP1 important in double-strand DNA damage sensing, repair, and tumor suppression
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  • Genetics in Radiation HR (homologous repair) efficient in late S or G2 phase when sister chromatids have replicated but not separated Repair is cell cycle dependent Undamaged homologous chromosome or sister chromatid or replicated chromosome is used as a template to fill in missing DNA sequences in damaged chromosome
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  • Genetics in Radiation Human tumor cells block in G2 after DNA double-strand damage, when repairs are detectible, and irradiation induced G2 checkpoint allows more time for cells to undergo HR (homologous repair) and survive radiation
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  • Genetics in Radiation NHEJ (nonhomologous endjoining) is where blunt ends of chromosomes severed by radiation are directly rejoined Less cell cycle dependent Highly mutagenic due to template-free rejoining lacks specificity of HR Ends of different chromosomes can be rejoined, leading to chromosomal aberrations or expression of dangerous fusion proteins
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  • p53 Tumor Suppressor Gene p53 stops activity of tumors Loss or mutation of p53 predisposes to cancer (e.g. inheriting only one functional copy of p53 gene from parents) p53 protein binds DNA