Radiation Oncology Most common cancer diagnosis in 2022 Prostate followed by breast. Most common cancer related deaths in 2020 Lungs, followed by colorectal. Cancer mortality trends Has been decreasing due to advanced in treatments such as radiology. Intent of treatment when diagnosed. Curative Definitive Noeoadjuctive Adjuctive Palliative Pain Bleeding Obstruction Treatment is tailored based on the above two. Modalities Surgery -> most commonly known . Radiation Systematic therapy Things to consider when choosing: Histopathology Stage Patient factors: such as frailty, other cormbolities , performance, patient preference Treatment: previous treatment and contradictions to treatment, such SLE as these patient get side effects when given radiation. Basics of radiotherapy Effective for many types of cancer 50% of patients should have radiotherapy at some points Types: Nonidionising : such as radiofrequency radio waves found in X-rays and Cts . 20 to 150 kv . Ionising: higher energy -> can kill DNA -> hence, this is the type of radiation that is used. There are different types. We use superficial radiotherapy for thigs like skin cancers, while internal cancers we use megavoltage radiotherapy. Dose: measured in Gray -> absorption of 1 joule of energy per kg of matter. Fraction: number of treatments delivered. Uses high frequency of radition that delivers ionising events in tissue -> DNA damage of cells at area of inttesrs Direct: deposits ionsiign energy in cells Indirect: water molecules ionised -> free radicals -> damage DNA of cells. Differentiated cell kill: cells vary in suscebility to inioing raditioam . Malignant cells cannot repair DNA once damaged. Normal cells such as normal hair cells etc. can repair DNA after damage. Therapeutic area Aim to maximse therapeutic ration > maximise response with minimal side effects i.e. without doing much damage to normal healthy cells. Types of radiotheraoy May be used before the surgery to shrink the cancer May be used after the main treatment, that is surgery. External -> from outside External beam radiotherapy -> most common form. The linear accelerator Electron gun that shoots electrons, which get accelerate in the accelerating wave guard -> do a little loop -> then will turn into photons -> the photons are what will hit the patient. Cyperknife Used for small sized tumors at small and snesive area Robort arm to pinpoint where to go For example, brain tumors Uses gamma rays -> cobalt 60 Internal therpapy Brachytherapy Use of radioactive isotopes. Palliative radiotherapy Spinal cord compression -> to be treat within 24 hours. In first instance give dexamethasone to decrease swelling and help alleviate the swelling a bit Follow with radiotherapy. Bome pain Brain metastasis Bleeding -> gastric cancer Process of radiation Initial consult Radiotherapy stimulation Immobilisation -> reproduce position for treatment. Exact same position should be able to be reproduced multiple times, as the patient will have to get the therapy multiple times and will need to get it done at multiple days -> this is because if they move, then it will be targeted to different organs. CT scan of patient in treatment position Radiotherapy planning Target organ and how much needs to be treated. Organs at risk These days we use 4D radiation planning -> mainly in cancers that move? 4D planning takes into account how the tumor moves and where it is, at different stages of the breathing cycle. PETCT fusion for radiation Modulated radiotherapy -> allows the beam to target all points at all points in time? And protects the parts that you do not want them to be targeted. Daily “real time” cone beam CT imaging -> however, this is not as a good as the actual CT -> but this is still needed to be done everyday to improve the accuracy of the radiation. It can also help us see tumor change from day to day treatment -> such as tumor regression over time. Stereotactic radiosurgery Treatment Follow up.