Radiation Oncology

Introduction to Radiation Oncology – What Do We Do? Ibrahim Abu-Gheida MD Department of Radiation Oncology American University of Beirut Medical Center Post Graduate Year 4 January 2016

Outline • • • • •

Introduction What is Radiation Oncology Radiotherapy Consult Radiotherapy Planning Side Effects Monitoring / Intervention – Early – Late

• Summary / Conclusion

Discovery of X-rays • Dates Back to 1800’s • Wilhelm Conrad Von Rontgen – Physicist

• Studying cathode tube, he noted a new ray of greater penetrating power. • X-rays presented in 1895 • Nobel Prize in physics 1901

Discovery of X-rays • First X-ray image: • Roentgen Realized the shadows of his wife’s Finger bones and … • December 22nd 1895

Glasser O. Wilhelm Conrad Röntgen and the early history of the Roentgen rays. Springfield, IL: Charles C. Thomas, Publisher, Ltd., 1934, with permission.)

First Radiation Oncologist • Emil Grubbe • Medical Student • Used X-rays to treat a 65 yo female with recurrent breast carcinoma at a lamp factory in Chicago • Jan 1896

Discovery of Natural Radioactivity • Henri Becquerel • March 1896 • Blackened photo glasses despite being kept in total dark • Discovered natural radioactivity.

Discovery of Radium • Marie and Pierre Curie 1898

• 1903- 1904 Radium began to be used in treatment of patients with skin cancer – France.




Definition Of Radiation Oncology • Discipline of human medicine concerned with the generation, conservation, and dissemination of knowledge concerning the causes, prevention, and treatment of cancer and other diseases involving special expertise in the therapeutic applications of ionizing radiation.

Perez and Brady’s Principles and Practive of Radiation Oncology. 6th Edition.

Radiation Oncology • Principle that exist at the juncture of physics and biology, Radiation Oncology addresses the therapeutic uses of ionizing radiation alone or in combination with other treatment modalities – – – – – –

Biologic therapies Surgery Drugs Oxygen Heat Others…

Radiation Oncology • Also Radiation Oncology is concerned with the fundamental principles of cancer biology • The biologic interaction of radiation with normal and malignant tissue • Physical basis of therapeutic radiation. • As a learned profession, radiation oncology is concerned with clinical care, scientific research, and the education with the professionals within the discipline and amongst other specialists

Radiation Therapy • Radiation Therapy aims to deliver a precisely measured dose of irradiation to a defined volume with as minimal damage as possible to surrounding healthy tissue – Curative efforts • Local Tumor Control

– Palliation of symptoms • Improves QOL

– Prevention of symptoms • E.g. Spinal Cord Compression




So What Happens When you Consult us?

The Planning And Conduct of a Course of RT • • • • •

What is the indication for RT? What is the goal of RT? What is the planned treatment volume? What is the planned treatment technique? What is the planned treatment tumor dose and fractionation? • What is the radiation tolerance of the surrounding normal tissue / Organs at risk?

What Do we Do? - Volume • Volume that needs to be irradiated for achieving desired curative or palliative goal – Visualized or palpable tumor mass? – Mass and surrounding lymphatics? – Microscopic disease spread?

Volume - Example • Medulloblastoma • Surgery alone, almost all patients relapse both locally and by leptomeningeal dissemination via CSF • Thus RT volume for patients with intermediate / high risk disease will be the entire craniospinal axis

Volume – Example 2 H&N

Technique Teletherapy (External Beam RT)

Brachytherapy

Cobalt – 60: X-rays Linear – accelerator : Photons / Electrons / Neutrons Gama Knife Cyber Knife Proton Therapy Heavy ion therapy : Carbon therapy RT Fields: • Parallel opposed fields • Four fields • Multiple fields IMRT / IGRT / IMPT Stereotactic RadioSurgery (SRS) RadioTherapy (SRT) Stereotactic Body RadioTherapy (SBRT) / SABR

Radioactive implant • Interstitial brachytherapy (Soft – tissue sarcoma) • Intracavitary brachytherapy (Cervical) • Mold therapy (eg skin)

RT- Dose / Fractionation • Must determine the correct number of RT fractions per day • Correct dose per fraction • Proposed total dose of RT • Dose rate (RT given per minute) – HDR VS LDR

• Usually driven by trt goal, volume and technique

RT- Dose / Fractionation

Normal Tissue Tolerance • Probability of Acute and Late Radiation Side Effects is a function of dose, dose fractionation, Patient, environmental exposure etc…

RT Consult • These Fundamental Questions are addressed not only the the treating physician, but should also be presented to the patients… • Informed Consent for RT. • So What Happens Next ???




EBRT Treatment Planning

EBRT Treatment Planning • Contouring

• Fields drawn

• Inverse planning done (IMRT)

EBRT Treatment Planning • Medical Physics team run the RT plan • Plan reviewed by the radiation oncologist • Upon approval, plan transmitted to treatment machine • Patient Repositioned as in CT simulation • Treatment Begins!!! • So Are we done??




Patient / Treatment Monitoring • During treatment , port films / IGRT – Done on Almost Daily basis – Checked and Reviewed by the Radiation Oncologist

• Clinical evaluation – Monitor side effects

RT Side Effects – Patient Related Factors – General condition – Age – Comorbidity – Genetic syndromes – Infection – Interaction with other treatments – Smoking – Gender

RT Side Effects – Radiobiological Related Factors – Intrinsic Radiosensitivity – Total RT dose – Technique and RT volume – Fractionation schedule (late toxicity) – Overall Treatment time (early toxicity) – Concomitant treatment

•All Side Effects : Best treatment is Prevention!!!

Early Side Effects • Skin – Acute edema or erythema  Biafine / Silver Sulphazidime / Aquaphore – Pruritis  Steroid based cream for limited duration – Hair Loss **Beware of Herpes Reactivation**

Early Side Effects • CNS: Side Effect

Treatment

Fatigue / Somnolence

Sleep

Brain / Tumor Edema

Steroids

• CNS / Stomach: Side Effect

Treatment

Nausea / Vomiting

Ondansetron “Zofran” / PPI

Side Effect

Treatment

Conjunctivitis / Keratitis

Cortisporin opthalmic

• Eye:

Dry Eyes

Artificial Tears

Early Side Effects • Pelvis: Side Effect

Treatment

Diarrhea  RO Infection

Loperamide “Imodium” / Atropine/diphenoxylate “Lomotil”

Proctitis

Proctofoam / Proctoglyvenol / Proctosynalar

Dysuria / Hematuria  RO Infection

Cranberry / GYN-Delta

Urinary Obstructive Symptoms Tamsulosin “Omnic” Vaginal Candidiasis

Floconazole

Vaginitis

Moisturizer

**Beware of Herpes** **Avoid DRE  Unless absolutely warranted**

Early Side Effects • Head And Neck: Side Effect

Treatment

Oral Mucositis

NaHCO3 / Magic Solution(Lidocaine based) / Pain medications

Candidiasis

Fluconazole **Beware of Herpes**

Early Side Effects • Lung: – Acute pneumonitis (Graded)  Prednisone / Oxygen / Antibiotics **Key is Early Detection**

Late Side Effects – Post 6 months of RT • Skin reaction – Talengectasia

– Arm lymphedema

Late Side Effects • Head And Neck: – – – –

Fibrosis Jaw Bone oesteonecrosis  When Dental Procedures post RT Xerostomia  avoid with new planning techniques (IMRT) Endocrinological side effects: • Thyroid / Pituitary

• Pelvis: – – – – –

Chronic Hematuria / RT cystitis Proctitis Hematochezia Vaginal Stenosis Vaginal Dilators Infertility Risk  sperm banking

Late Side Effects • Lung Fibrosis: – Usually in patients that developed RT pneumonitis

Late Side Effects • CNS – Cognitive deficits (1-2 years)

• Secondary Malignancies – Several decades later – Risk much smaller than recurrent primary cancer – In adults, > 90% of RT secondary cancer are due to increased life expectancy – Related to dose and volume of RT




Summary • Radiation Oncology is a wide discipline that integrates may physical, biological, and clinical sciences for generation, conservation and dissemination of knowledge concerning the causes, prevention and treatment of cancer and other diseases using precise Ionizing Radiation +/- other treatment modalities • Many different techniques , new developments – Brachytherapy, SRS, SRT, SBRT/ SABR, Gamma Knife, Cyber Knife, Proton therapy Carbon Therapy, etc…

Summary • Radiation Oncologist can and must aid in treatment decisions for cancer patients and other non-malignancy related cases that can be treated with RT – E.g. : Keloids, exopthalmus etc…

• Radiation therapy does not only imply correct treatment planning but also close treatment monitoring and patient evaluation for both early and late side effects

Finally It requires a great deal of Team Work

Thank You!!!

References • Perez & Brady’s Principle and Practice of Radiation Oncology 6th Edition (2013) • Joiner & Van Der Kogel. Basic Clinical Radiobiology 4th edition (2009) • Beyzadeoglu , Ozyigit, Ebruli, Basic Radiation Oncology (2010)

Radiation Oncology - Introduction

Radiation Oncology - Introduction

Suggest Documents