MicroBio 160 1st Edition Lecture 9 Outline of Current Lecture I Why screen a Early detection b Warning signs II Types of Tests III Imaging Techniques IV PET scans a Risky V False results VI Sensitivity and Specificity VII Ideal screening VIII Is early detection beneficial IX Treatments X Treatment intent Current Lecture Why screen Screening tests can help find cancer at an early stage before symptoms appear When abnormal tissue or cancer is found early it may be easier to treat or cure o By the time the symptoms appear the cancer may have grown and spread this can make the cancer harder to treat ore cure o Screening tests are done when you have no cancer before you notice any signs These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute You are trying to establish a baseline of tests to see what the person looks like when they re healthy compare to later on when they have it Early detection increases 5 year survival rate Yellow stage 2 or 3 Red stage 4 metastasized Almost 100 can be detected early Warning signs Fatigue weight loss night sweats blood in urine chronic cough loss of appetite recurrent fever sudden depression new persistent pain enlarged lymph nodes recurrent nausea or vomiting blood in stool a recent change in bowel habits and changes in the size or color of a mole or changes in a skin ulcer that doesn t heal Just because you have the symptoms doesn t mean you have the disease Can be grouped Cancers can give off chemicals that will alter your brain chemistry Types of tests Physical exam and history an exam of the body to check general signs of health including checking for signs of disease such as lumps or anything else that seems unusual o History of the patient s health habits and past illnesses and treatments will also be taken Laboratory tests medical procedures that test samples of tissue blood urine or other substances in the body Imaging procedures procedures that make pictures of areas inside the body Genetic tests tests that look for certain gene mutations that are linked to some type of cancer Imaging Techniques MRI Magnetic Resonance Imaging uses magnets to energize electrons release of energy image GBM Ultrasound uses sound waves Conventional x ray ameloblastoma CT or CAT scan Computed Tomography scan uses multiple high resolution x rays to generated a composite image lung cancer PET Positron emission tomography scans a nuclear medical imaging technique that produces a 3 dimensional image or picture of functional processes in the body Detects pairs of gamma rays emitted indirectly by a positron emitting radionuclide tracer which is introduced into the body on a biologically active molecule o 3 dimensional images if tracer concentration within the body are the constructed by computer analysis If the biologically active molecules chosen for PET is FDG a glucose analog the concentrations of tracer imaged given tissue metabolic activity in terms of regional glucose uptake Uses of this tracer to explore the possibility of cancer metastasis is the most common type of PET scan in standard medicare care 90 of current scans Radioactivity glucose and sugar Use a sugar analog o Look for metabolic activity Cancer shows up more because it has a higher metabolic rate Is it risky There are certain tests that do have risk not all screening tests are helpful and most have risks must weigh risks against the benefit o Some screening procedures can cause bleeding It is important to know the risks of the test and whether it has been proven to decrease the chance of dying from cancer False results Screening tests can be abnormal even though there is no cancer there false positive test o Can cause anxiety and is usually followed by more tests and procedures which also have risks Screening tests can be normal even though there is cancer there false negative test o Problem you might have to undergo even more rigorous tests o May delay seeking medical care even if there are symptoms Sensitivity and Specificity Sensitivity What percentage of people that have cancer of a certain type actually have that cancer detected with a particular test looking for a specific cancer o If a test is not sensitive there will be a lot of false negative results Specificity trying to determine whether or not people actually have the cancer o If a screening test isn t very specific it will yield many false positives Ideal Screen no false positives no false negative does not exist Looking at a field of healthy individuals Minimize the number of false positives people who don t have cancer Minimize the number of false negatives people who have cancer o The perfect screen would never have any false positive results or false negative results DOESN T EXIST Is early detection beneficial Some cancers never cause symptoms and never become life threatening should they bother telling them are the treatments helpful o Treatments for cancer have side effects o For some cancers finding and treating the cancer doesn t improve the chance of a cure or help the person live longer something to help fight their cancer Pancreatic Treatments Surgical removal of tumor or part of a tumor o Aka resection total or partial Chemotherapy treatment of cancer with one or more cytotoxic antineoplastic drugs chemotherapeutic agents as a part of a standardized regimen Traditional kills rapidly dividing cells indiscriminately Targeted antibody therapy o The original chemotherapy was a derivative of mustard gas used in WWI o Mustard gas was a powerful suppressor of blood production During WWII Yale researchers gave venous injections of nitrogen mustards to lymphoma patients with temporary but remarkable results Chemo details There are over 100 different drugs available to treat cancer Each has different properties and functions for destroying cancer cells o Alkylating agents destroy the DNA of a cell to prevent it from reproducing Anttumor antibiotics destroy the enzyme a cell needs to reproduce its DNA o Can treat with mitotic behaviors prevent cells from obtaining the protein needed for survival o Routes of administration pill intramuscular injection IM intravenous administration IV Radiation can be targeted more we can control the size of the bean concentration medical use of ionizing radiation Radiation therapy damages DNA Purpose is to chop DNA into as many different pieces not able to produce proteins o Can induce apoptosis o Given
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