Department of Radiation Oncology

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Radiation Oncology Elective

Welcome to Radiation Oncology!

This is a brief summary of what we hope you will get out of your elective rotation in the Department of Radiation Oncology. First and foremost, we want you to perfect your ability to take a focused Patient History and do a thorough Physical Examination. Depending on your assigned radiation oncology service, you will learn the art of various cancer-specific physical exams, including proper lymph node, head and neck, and female pelvic exams. Also, we want you to learn about the natural history of some cancers. To do this, you will have to do some reading. Feel free to ask the Attendings and Residents for guidance in terms of books and specific references.

We do not expect you to become a radiation oncologist, or decide to be one by the end of your rotation, but we do want you to understand the overall care of patients who have cancer, and that although patients may not always be cured, they can be helped to feel and live better. That is the most important thing. Sometimes the treatment plans will include radiation oncology and sometimes they will not. When you see the patient, we want you to ask yourself, what is the best thing to do for this patient? To answer that question honestly, you will have to know more than radiation oncology; you must know what the surgeons can do, what the medical oncologists can do, what the bone marrow transplant team can do, and what can specific services do, such as anesthesia for pain relief or rehabilitation medicine for specific problems. We do not particularly want you to worry about what doses and fields are appropriate. We do want you to learn about how we try to set up radiation fields and what our concerns are for normal tissues. You may wish to do some reading on radiation side effects. Again, your Attendings can guide you.

In the last week of your elective, we will expect you to make a 20-minute powerpoint-based formal presentation to the department on any subject of your choosing, insofar as it relates to cancer. The staff can give you advice to help you choose an interesting topic.

There is not a single medical school in the country that will teach you about cancer as a series of chronic disease processes. You will find in radiation oncology that our daily interaction with the patients is quite intense, in many ways more intense than what the surgeons and medical oncologists have. Whether it is before, during, or after their course of radiation therapy, patients become well-known to you and to the department.

We hope that you will enjoy this rotation and consider it an opportunity to become aware that there are people who treat malignant diseases, both on and off clinical study. There are many things that can be done to help cancer patients and all of us continue to learn. We hope you will be learning with us.

Finally, a word on professionalism. The Department expects that all personnel will conduct themselves in a professional manner that optimizes patient care as well as resident and student teaching. If anyone behaves inappropriately, we expect you to bring this to our attention promptly.

Radiation Oncology 300: A Primer for Medical Students

Course Director: Neha Vapiwala, M.D.
Course Coordinator: Cordelia Baffic
Dept. Phone # (215) 662-3694
Fax # (215) 349-5949
Email address: baffic@xrt.upenn.edu

Goals of the Course

  1. To understand the role of radiation therapy in the treatment of cancer.
  2. To learn more about the general principles of oncology, including
    • Basic Science of Oncology
    • Diagnostic workup and staging of cancer
    • Tumor boards and deciding on a cancer treatment plan.
    • The administration of treatment for cancer
    • The supportive medical care of the cancer patient, particularly outpatient care
  3. To observe the specialized procedures of radiation therapy for cancer, including
    • General simulation and treatment of common radiation therapy fields.
    • Planning and administration of CT-planned conformal radiation therapy.
    • Planning and administration of brachytherapy.
    • Intraoperative photodynamic therapy.

Medical Student Assignment:

In order to maximize interaction between student and faculty, each student will be assigned to work with one attending (and his/her resident) for the entire 4-week rotation.

Tumor Boards and Conferences:

The medical student is expected to attend conferences relevant to the service to which they are assigned.Conferences are in 2 Donner unless otherwise noted.

Below is a general outline of conferences in a typical week.

Medical Student Responsibilities

  1. Consultations: For the first consultation, the student will observe the resident as he/she gathers the pertinent information (x-rays, path reports, operative reports, etc.) and does an H&P on the patient. For this first consult, the resident will present the case to the attending while the student looks on. For all subsequent consultations, the student will see and examine the patient first. The student will then present the case to the Attending and the Resident together. The student will handwrite a consultation note, which will be reviewed by the Attending and Resident.
  2. Follow-Up Visits and On-treatment Visits: The student will see and examine the patient together with the resident, in a format similar to hospital rounds. The student will assist the resident in obtaining pertinent information (e.g. lab or x-ray results; updating the patient’s medication list; scheduling tests or appts with other M.D.’s). The student is not expected to write a note on these patients.
  3. Simulations, Dosimetry, and Setups: The student will observe the attending and resident in the technical aspects of radiation oncology. The student is expected to help in gathering the pertinent information (e.g. x-rays) necessary for these procedures. The student may be quizzed about anatomy and oncology during these procedures, but is not expected to perform any of these technical procedures.
  4. Presentation: A requirement of the rotation is a 15-20 minute powerpoint-based presentation on any topic of the student's choice. Ideally the topic should be discussed with and approved by the program director and the attending the student is working with, and should be oncology-related in nature. For example, the talk can be based on a particularly interesting case that the student observed during the rotation, or it can be a general overview on a particular new drug or rare oncologic entity. The talk is typically followed by a question and answer period. A handout corresponding to the talk is optional but generally preferred.

Grading (Honors, High Pass, Pass, Fail, Incomplete)

The attendings who have worked with the student will report back to the course directors with written comments on the student’s performance and a tentative grade. As noted above, for the grade of honors, the student must lead a morning or noon case conference. This does not guarantee a grade of honors but is required for the grade to be considered.

Oncolink

Highly motivated students interested in a career in radiation oncology should be prepared to submit a short article to Oncolink, the University of Pennsylvania’s Internationally recognized cancer web site. This can be a version of the student’s brief handout that he/she did for the case conference, or another "interesting" case of the month. Films and/or pathology slides can be scanned by the Oncolink editorial staff and converted into graphical format to accompany text. See www.oncolink.upenn.edu.

Research Opportunities

The department offers opportunities for clinical and/or basic science research for highly motivated students interested in a career in radiation oncology. In general, the one-month rotation of RO300 is not sufficient time to design and implement even a simple research project. However, separate 1-2 month rotations in radiation oncology focusing on clinical research projects are available (RO400). These are generally "chart review" type projects. Longer rotations in the department’s oncology research laboratories are also available. Some laboratory and/or clinical research positions in the department offer students a modest stipend.

Suggested Reading for RO 300:

Coia et al.: Introduction to Radiation Oncology -- (aka Radiation Oncology for the House Officer)

This is the traditional book that is purchased by medical students for this course.

AJCC Cancer Staging Manual (most recent edition)

The staging manual is important for anyone who is interested in any field of oncology. Copies are available at many locations throughout the dept.

DeVita: Cancer: Principles and Practice of Oncology --- the chapters on breast cancer, lymphomas, lung cancer, head and neck cancer, cervix cancer and prostate cancer. This massive textbook is available at the med school library or in multiple locations throughout the radiation oncology dept. (residents’ room, etc.)

The results of major large randomized trials in oncology that may be of interest to medical students are usually published in the New England Journal of Medicine, Lancet, or the Journal of Clinical Oncology. These journals occasionally have good review articles on important topics in oncology as well. The major journal specific to the field of radiation oncology (International Journal of Radiation Oncology Biology Physics) is probably too technical and esoteric for most medical students.

Steps involved in Clinical Radiation Therapy

  1. Consultation, including decision to irradiate
  2. Pre-radiation workup, including staging, dental evaluation, nutritional assessment
  3. Simulation, including immobilization of the area to be irradiated
  4. Dosimetry (Calculation of radiation dose to tumor and normal structures)
  5. Setup or final quality assurance planning session
  6. Radiation Treatments, including on-treatment visits by the physician(s)
  7. Conedown(s) --- if applicable ---- : Repeat of steps 3 through 6
  8. Post-radiation follow-up visits

Examples of Indications for Radiation Therapy

Definitive Radiotherapy alone for early larynx cancer.

Preoperative Radiotherapy prior to resection of a low-lying rectal cancer.

Postoperative Radiotherapy after mastectomy for locally advanced breast cancer.

Palliative Radiotherapy for a massive incurable lung cancer causing pain/bleeding

Benign (rarely used) Radiotherapy to prevent coronary artery restenosis after PTCA.

Different Radiation Therapy Dose Fractionation Schedules

(1 cGy = 1 rad = approximately the radiation dose absorbed in getting a typical CT scan)

Conventional Radiotherapy 180-200 cGy/day, 5 days/wk to 6600-7200 cGy; no planned interruptions

Accelerated Hypofractionated Radiotherapy 250-300 cGy/day, 5 days/wk to 5000-5400 cGy; no planned interruptions

Non-accelerated Hypofractionated Radiotherapy 250-300 cGy/day, 3-4 days/wk to 5000-7000 cGy; no planned interruptions

Split course Radiotherapy 200-300 cGy/day, 5 days wk to 6000-7200 cGy; 1-2 wk break in the middle of therapy

Hyperfractionated Radiotherapy 110-125 cGy b.i.d., 5 days wk to 7000-8000 cGy; no planned interruptions

Accelerated Hyperfractionated Radiotherapy 140-160 cGy b.i.d., 5 days wk to 6600-7200 cGy; usually requires 1-2 wk break in the middle of therapy

Accelerated, Concomitant Boost Radiotherapy 180-200 cGy/day, 5 days wk to 3500-4500 cGy followed by 150-180 cGy b.i.d. "conedown" boost radiotherapy to 6600-7200 cGy; no planned interruptions

Continuous Hyperfractionated Accelerated Radiotherapy 120-180 cGy b.i.d or t.i.d. 7 days wk to 5000-5400 cGy; no planned interruptions

The Four "R’s" of Radiation Biology

Repair: Cells repair DNA damage from radiation in between radiation fractions (doses). Larger radiation doses, radiation sensitizers (e.g. concurrent chemotherapy) partly overcome repair.

Redistribution: Cells "redistribute" from radioresistant phases (e.g. S phase) of the cell cycle to more radio-sensitive cell cycle phases (e.g. M phase) in between radiation fractions Hyperfractionated radiotherapy (increased number of XRT fractions increases the probability of cells being in M phase during a treatment).

Reoxygenation: Cells may go from a hypoxic (and thus radioresistant) environment to a well-oxygenated state as a course of treatment proceeds Hyperfractionated radiotherapy; hypoxic cell sensitizers; carbogen or hyperbaric oxygen during XRT.

Repopulation: Cells may respond to the death of adjacent cells by "accelerated repopulation" Accelerated radiotherapy kills off cells before they gain the opportunity to repopulate.

Glossary of Terms Related to Radiation Therapy

Adjuvant: Generally refers to postoperative therapy. However, chemotherapy given after "definitive" radiotherapy would also be considered adjuvant.

Blocks: Thick shields made of a lead-like alloy which can be shaped for each patient to "block" portions of their anatomy that would otherwise fall into the radiation field. In the treatment of head and neck cancer, for example, every attempt is made to block as much CNS tissue as possible.

Brachytherapy: radiotherapy given in the form of radioactive sources placed directly into or around a patient’s tumor. This may be given interstitially (sources imbedded directly into tissue) or intracavitary (sources laid into a cavity such as the nasopharynx.

cGy (centigray): A modern basic unit of radiotherapy dose; 1 cGy = 1 rad. One cGy = 100 ergs per gram of absorbed energy.

Cobalt-60 therapy: A form of external beam radiotherapy in which the source of radiation is not x-rays, but gamma rays emitted from a machine containing radioactive Cobalt-60.

Conedown: Shrinking the field size sometime during the course of radiotherapy, to take advantage of the decreasing size of tumor during treatment and to minimize the amount of toxicity of treatment. For example, a patient may begin radiotherapy with a 15 x 15 cm field and then have a conedown midway through treatment to a 10 x 10 cm field.

Conformal Radiotherapy: The use of extremely sophisticated imaging studies and dosimetry to design radiation fields that "conform" precisely to the shape of a patient’s tumor. Conformal radiotherapy usually uses smaller "safety margins" around a patient’s tumor, a larger number of fields, and less prophylactic radiotherapy of clinically uninvolved lymph node areas.

Consolidative: Refers to radiotherapy given after a maximal or complete response to chemotherapy, as is often done in the treatment of lymphomas.

Course: A series or program of radiation treatments or fractions with a specific goal in mind for a patient, e.g. a seven-week course of daily radiotherapy to the lung for attempted cure.

Definitive: Refers to radiotherapy given with the intention of cure without radical surgery. May be given with other non-surgical treatment such as chemotherapy.

Dosimetry: The process of optimizing the radiotherapy fields and dose by calculating the radiation dose to be received by a tumor and/or normal tissues in a radiation field(s). Physicists and "dosimetrists" work with the radiation oncologist in comparing possible radiation treatment plans with the goal of maximizing the radiation dose to the tumor while minimizing dose to normal tissue, often requiring sophisticated computer programs. Dosimetry can be described as the radiotherapy version of pharmacokinetics.

External beam radiotherapy (x-ray therapy): radiotherapy given from a machine (usually a linear accelerator) which produces a high-energy x-ray beam which is then aimed at a patient’s tumor and/or suspected tumor areas.

Field: An area at which a radiotherapy beam is directed, usually described as a rectangular shape, in cm (e.g. 10 x 14 cm). "Blocks" are often used to further customize the shape of a field. A single fraction of radiotherapy may include multiple fields, typically two to four.

Fraction: A single radiation therapy session, usually given over one to three minutes. A fraction may consist of one or multiple "fields," and any dose, as prescribed by the radiation oncologist. Most courses of radiotherapy involve one fraction per day, Monday through Friday, over one to seven weeks, although an infinite number of possible fractionation schedules are possible.

Gy (Gray): The SI modern basic unit of radiotherapy dose; 1 Gy = 100 cGy = 100 rad. One Gy = 1 Joule per kilogram of absorbed energy.

Hyperfractionation (see also fraction): The delivery of two or more radiation fractions per day, generally given with a four or more hour interval between fractions.

Neoadjuvant: Generally refers to preoperative therapy. However, chemotherapy prior to "definitive" radiotherapy would also be considered neoadjuvant.

Palliative: Refers to therapy given with the goal of relieving distressing symptoms, without any anticipated effect on survival.

Prophylactic: Refers to radiotherapy given to a site at which there is no known tumor but which is considered to be at high risk for harboring occult "microscopic" disease, such as lymph node areas.

Rad: Basic unit of radiotherapy dose; terminology has now changed to the S.I. units (cGy and Gy). 1 rad = 1 cGy (See Gray).

Radiation Therapy Oncology Group (RTOG): A National Cancer Institute-sponsored multicenter clinical trials cooperative group which performs studies related to radiation therapy, including many lung cancer studies.

Radiosensitizers: Drugs or other treatments which increase the cellular response to radiotherapy. Many chemotherapeutic drugs have radiosensitizing properties.

RTOG: See Radiation Therapy Oncology Group.

Safety Margin: A margin of "normal-appearing" tissue which is added onto the visible tumor area for the purposes of radiation planning. Typically 1.5-2 cm in all dimensions is added, to account for microscopic extension of tumor cells and the possibility of slight patient motion during treatment.

Simulation: A detailed planning session for radiation therapy, which "simulates" but does not actually deliver a radiation treatment. Simulation consists of immobilization of the patient in an appropriate position for radiation therapy, marking the patient’s skin, localizing the area to be treated under fluoroscopy, taking radiographs of the area to be treated, and taking measurements of the patient’s contour for dosimetry purposes.

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