Presentation on Basics and Recent advances in radiation oncology

1. Dr. Kandra Prasanth Reddy, MD
Consultant Radiation Oncologist
American Oncology Institute, LB Nagar
Recent Advances In Radiation
Oncology

2. Introduction
 Radiation has been an effective tool for
treating cancer for more than 100 years
 More than 60 percent of patients diagnosed
with cancer will receive radiation therapy as
part of their treatment
 Radiation oncologists are cancer specialists
who manage the care of cancer patients with
radiation for either cure or palliation
Patient being treated with modern
radiation therapy equipment.

3. Overview
 What is the physical and biological basis for radiation
 What are the clinical applications of radiation in the
management of cancer
 What is the process for treatment
 Simulation
 Treatment planning
 Delivery of radiation
 What types of radiation are available
 Summary

4. What Is the Biologic Basis for
Radiation Therapy?
 Radiation therapy works by damaging
the DNA of cells and destroys their
ability to reproduce
 Both normal and cancer cells can be
affected by radiation, but cancer cells
have generally impaired ability to
repair this damage, leading to cell
death
 All tissues have a tolerance level, or
maximum dose, beyond which
irreparable damage may occur

5. Fractionation: A Basic Radiobiologic
Principle
 Fractionation, or dividing the total dose into small daily fractions
over several weeks, takes advantage of differential repair abilities
of normal and malignant tissues
 Fractionation spares normal tissue through repair and
repopulation while increasing damage to tumor cells through
redistribution and reoxygenation

6. The Four R’s of Radiobiology
 Four major factors are believed to affect tissue’s response to
fractionated radiation:
 Repair of sublethal damage to cells between fractions caused by radiation
 Repopulation or regrowth of cells between fractions
 Redistribution of cells into radiosensitive phases of cell cycle
 Reoxygenation of hypoxic cells to make them more sensitive to radiation

7. Clinical Uses for Radiation Therapy
 Therapeutic radiation serves two major
functions
 To cure cancer
 Destroy tumors that have not spread
 Kill residual microscopic disease left after
surgery or chemotherapy
 To reduce or palliate symptoms
 Shrink tumors affecting quality of life, e.g., a
lung tumor causing shortness of breath
 Alleviate pain or neurologic symptoms by
reducing the size of a tumor
External beam radiation
treatments are usually scheduled
five days a week and continue for
one to ten weeks

8. Radiation Therapy in Multidisciplinary
Care
 Radiation therapy plays a major role in the
management of many common cancers
either alone or as an adjuvant therapy with
surgery and chemotherapy
 Sites commonly treated include breast,
prostate, lung, colorectal, pancreas, esophagus,
head and neck, brain, skin, gynecologic,
lymphomas, bladder cancers and sarcomas
 Radiation is also frequently used to treat
brain and bone metastases as well as cord
compression

9. Palliative Radiation Therapy
 Commonly used to relieve pain from bone cancers
 ~ 50 percent of patients receive total relief from their
pain
 80 to 90 percent of patients will derive some relief
 Other palliative uses:
 Spinal cord compression
 Vascular compression, e.g., superior vena cava
syndrome
 Bronchial obstruction
 Bleeding from gastrointestinal or gynecologic tumors
 Esophageal obstruction
Radiation is effective therapy for relief
of bone pain from cancer

10. Wilhelm Roentgen
 Wilhelm Roentgen discovered X-Rays in 1895
 He was performing experiments on electricity, when he noted that an
energy ray was produced which passed through most objects, including
his own body
 The field of Radiation Therapy - now known as Radiation Oncology -
was born shortly after this discovery
 The first diagnostic x-ray was taken within 2 months of Roentgen’s
discovery

11. Marie Sklodowska Curie
 While working at the Sorbonne in Paris, Marie and her husband Pierre
Curie isolated the first known radioactive elements
 These elements were named Polonium and Radium

12. Emil Grubee
 After noting the peeling of his hands exposed to x-rays,
medical student Emil Grubbe convinced one of his professors
to allow him to irradiate a cancer patient
 The patient was suffering from advanced breast cancer
 Grubbe became the World’s first Radiation Oncologist

13. Claude Regaud
• After seeing the cancer patient benefit from Grubbe’s intervention,
people began to understand the potential value of radiotherapy
• A professor at the Radium Institute in Paris, Glaude Regaud,
recognized that treatment may be better tolerated and more
effective if delivered slower and in smaller doses per day over
several weeks
• This process is known as fractionation

14. Kilovoltage X-Ray 1920

15. Telecobalt 1970s

16. Linear Accelerator

17. Methods of Delivering Radiation Therapy
Early 1950s Today

18. The Radiation Oncology Team
 Radiation Oncologist
 The doctor who prescribes and oversees the radiation therapy treatments
 Medical Physicist
 Ensures that treatment plans are properly tailored for each patient, and is responsible for
the calibration and accuracy of treatment equipment
 Dosimetrist
 Works with the radiation oncologist and medical physicist to calculate the proper dose of
radiation given to the tumor
 Radiation Therapist
 Administers the daily radiation under the doctor’s prescription and supervision
 Radiation Oncology Nurse
 Interacts with the patient and family at the time of consultation, throughout the treatment
process and during follow-up care

19. The Treatment Process
 Referral
 Consultation
 Simulation
 Treatment Planning
 Quality Assurance

20. Referral
 Tissue diagnosis has been
established
 Referring physician reviews
potential treatment options with
patient
 Treatment options may include
radiation therapy, surgery,
chemotherapy or a combination
It is important for a referring physician to discuss
all possible treatment options available to the
patient

21. Consultation
 Radiation oncologist determines
whether radiation therapy is
appropriate
 A treatment plan is developed
 Care is coordinated with other
members of patient’s oncology team
The radiation oncologist will discuss with the
patient which type of radiation therapy
treatment is best for their type of cancer

22. Simulation
 Patient is set up in treatment position on
a dedicated CT scanner
 Immobilization devices may be created to
assure patient comfort and daily
reproducibility
 Reference marks or “tattoos” may be
placed on patient
 CT simulation images are often fused
with PET or MRI scans for treatment
planning

23. Treatment Planning
 Physician outlines the target and organs
at risk
 Sophisticated software is used to carefully
derive an appropriate treatment plan
 Computerized algorithms enable the treatment plan
to spare as much healthy tissue as possible
 Medical physicist checks the chart and dose
calculations
 Radiation oncologist reviews and approves
final plan
Radiation oncologists work with medical
physicists and dosimetrists to create the
optimal treatment plan for each individualized
patient

24. Safety and Quality Assurance
 Each radiation therapy treatment plan goes through many
safety checks
 The medical physicist checks the calibration of the linear accelerator on
a regular basis to assure the correct dose is being delivered
 The radiation oncologist, along with the dosimetrist and medical
physicist go through a rigorous multi-step QA process to be sure the
plan can be safely delivered
 QA checks are done by the radiation therapist daily to ensure that each
patient is receiving the treatment that was prescribed for them

25. Delivery of Radiation Therapy
 External beam radiation therapy typically
delivers radiation using a linear accelerator
 Internal radiation therapy, called
brachytherapy, involves placing radioactive
sources into or near the tumor
 The modern unit of radiation is the Gray (Gy),
traditionally called the rad
 1Gy = 100 centigray (cGy)
 1cGy = 1 rad
The type of treatment used will depend on
the location, size and type of cancer.

26. Types of External Beam
Radiation Therapy
 Two-dimensional radiation therapy
 Three-dimensional conformal radiation therapy (3-D CRT)
 Intensity modulated radiation therapy (IMRT)
 Image Guided Radiation Therapy (IGRT)
 Intraoperative Radiation Therapy (IORT)
 Stereotactic Radiotherapy (SRS/SBRT)
 Particle Beam Therapy

27. Three-Dimensional Conformal Radiation
Therapy (3-D CRT)
 Uses CT, PET or MRI scans to
create a 3-D picture of the tumor
and surrounding anatomy
 Improved precision, decreased
normal tissue damage

28. Intensity Modulated Radiation Therapy
(IMRT)
 A highly sophisticated form of 3-D CRT
allowing radiation to be shaped more
exactly to fit the tumor
 Radiation is broken into many “beamlets,” the
intensity of each can be adjusted individually
 IMRT allows higher doses of radition to
be delivered to the tumor while sparing
more healthy surrounding tissue

29. Image Guidance
 For patients treated with 3-D or IMRT
 Physicians use frequent imaging of the
tumor, bony anatomy or implanted
fiducial markers for daily set-up
accuracy
 Imaging performed using CT scans, high
quality X-rays, MRI or ultrasound
 Motion of tumors can be tracked to maximize
tumor coverage and minimize dose to normal
tissues
Fiducial markers in prostate
visualized and aligned

30. Stereotactic Radiosurgery (SRS)
 SRS is a specialized type of external
beam radiation that uses focused
radiation beams targeting a well-
defined tumor
 SRS relies on detailed imaging, 3-D
treatment planning and complex
immobilization for precise treatment set-up
to deliver the dose with extreme accuracy
 Used on the brain or spine
 Typically delivered in a single treatment or
fraction

31. Stereotactic Body Radiotherapy (SBRT)
 SBRT refers to stereotactic radiation
treatments in 1-5 fractions on specialized
linear accelerators
 Uses sophisticated imaging, treatment
planning and immobilization techniques
 Respiratory gating may be necessary for motions
management, e.g., lung tumors
 SBRT is used for a number of sites: spine,
lung, liver, brain, adrenals, pancreas
 Data maturing for sites such as prostate

32. Proton Beam Therapy
 Protons are charged particles that deposit
most of their energy at a given depth,
minimizing risk to tissues beyond that point
 Allows for highly specific targeting of tumors
located near critical structures
 Increasingly available in the U.S.
 Most commonly used in treatment of pediatric,
CNS and intraocular malignancies
 Data maturing for use in other tumor sites
Proton Gantry
Source: Mevion

33. Types of Internal Radiation Therapy
 Intracavitary implants
 Radioactive sources are placed in a cavity near the tumor (breast,
cervix, uterine)
 Interstitial implants
 Sources placed directly into the tissue (prostate, vagina)
 Intra-operative implants
 Surface applicator is in direct contact with the surgical tumor bed

34. Brachytherapy
 Radioactive sources are implanted into the
tumor or surrounding tissue
 125I, 103Pd, 192Ir, 137Cs
 Purpose is to deliver high doses of
radiation to the desired target while
minimizing the dose to surrounding normal
tissues
Radioactive seeds for a
permanent prostate implant,
an example of low-dose-rate
brachytherapy.

35. Brachytherapy Dose Rate
 Low-Dose-Rate (LDR)
 Radiation delivered over days and months
 Prostate, breast, head and neck, and gynecologic
cancers may be treated with LDR brachytherapy
 High-Dose-Rate (HDR)
 High energy source delivers the dose in a matter
of minutes rather than days
 Gynecologic, breast, head and neck, lung, skin
and some prostate implants may use HDR
brachytherapy
LDR prostate implant

36. Permanent vs. Temporary Implants
 Permanent implants release small amounts of radiation over a period
of several months
 Examples include low-dose-rate prostate implants (“seeds”)
 Patients receiving permanent implants may be minimally radioactive and should avoid
close contact with children or pregnant women
 Temporary implants are left in the body for several hours to several
days
 Patient may require hospitalization during the implant depending on the treatment site
 Examples include low-dose-rate GYN implants and high-dose-rate prostate or breast
implants

37. Intraoperative Radiation Therapy (IORT)
 IORT delivers a concentrated
dose of radiation therapy to a
tumor bed during surgery
 Advantages
 Decrease volume of tissue in boost field
 Ability to exclude part or all of dose-
limiting normal structures
 Increase the effective dose
 Multiple sites
 Pancreas, stomach, lung, esophagus,
colorectal, sarcomas, pediatric tumors,
bladder, kidney, gyn
 Several recent trials have shown efficacy
for breast cancer

38. Systemic Radiation Therapy
 Radiation can also be delivered by an injection.
 Metastron (89Strontium), Quadramet (153Samarium) and Xofigo
(223Radium) are radioactive isotopes absorbed primarily by
cancer cells
 Used for treating bone metastases
 Radioactive isotopes may be attached to an antibody targeted at
tumor cells
 Zevalin, Bexxar for Lymphomas
 Radioactive “beads” may be used to treat primary or metastatic
liver cancer
 Y90-Microspheres

39. Radiation Therapy Basics
 The delivery of external beam radiation treatments
is painless and usually scheduled five days a
week for one to ten weeks
 The effects of radiation therapy are cumulative
with most significant side effects occurring near
the end of the treatment course.
 Side effects usually resolve over the course of
a few weeks
 There is a slight risk that radiation may cause a
secondary cancer many years after treatment,
but the risk is outweighed by the potential for
curative treatment with radiation therapy
Example of erythroderma after several
weeks of radiotherapy with moist
desquamation
Source: sarahscancerjourney.blogspot.com

40. Side Effects of Radiation Therapy
 Side effects, like skin tenderness, are
generally limited to the area receiving
radiation.
 Unlike chemotherapy, radiation usually
doesn’t cause hair loss or nausea.
 Most side effects begin during the
second or third week of treatment.
 Side effects may last for several weeks
after the final treatment.

41. Complications
 Acute Tissue Reactions
 Late Tissue Reactions

42. Acute Toxicity
 Time onset depends on cell cycling time
 Mucosal reactions – 2nd week of XRT
 Skin reactions – 5th week
 Generally subside several weeks after completion of treatment
 RTOG – acute toxicity <90 days from start of treatment (epithelial
surfaces generally heal within 20 to 40 days from stoppage of
treatment)

43. Late Toxicity
 Xerostomia
 Injury to serous acinar cells
 May have partial recovery
 Results in dental caries (in or outside of fields)
 Soft tissue necrosis
 Mucosal ulceration, damage to vascular connective tissue
 Can result in osteo-/chondroradionecrosis

44. Late Toxicity

45. Late Toxicity
 Fibrosis
 Serious problem, total dose limiting factor
 Woody skin texture – most severe
 Large daily fractions increase risk
 Ocular – cataracts, optic neuropathy, retinopathy
 Otologic – serous otitis media (nasopharynx, SNHL (ear treatments)

46. Late Toxicity
 Central Nervous System
 Devastating to patients
 Myelopathy (30 Gy in 25 fractions)
 Electric shock from cervical spine flexion (Lhermitte sign)
 Transverse myelitis (50 to 60 Gy)
 Somnolence syndrome (months after therapy)
 Lethargy, nausea, headache, CN palsies, ataxia
 Self-limiting, transient
 Brain necrosis (65 to 70 Gy) – permanent

47. Common Radiation Side Effects
Side effects during the treatment vary depending on site of the
treatment and affect the tissues in radiation field:
 Breast – swelling, skin redness
 Abdomen – nausea, vomiting, diarrhea
 Chest – cough, shortness of breath, esophogeal
irritation
 Head and neck – taste alterations, dry mouth, mucositis,
skin redness
 Brain – hair loss, scalp redness
 Pelvis – diarrhea, cramping, urinary frequency, vaginal
irritation
 Prostate – impotence, urinary symptoms, diarrhea
 Fatigue is often seen when large areas are irradiated
Modern radiation therapy techniques have decreased these
side effects significantly
Unlike the systemic side effects from
chemotherapy, radiation therapy
usually only impacts the area that
received radiation

48. Is Radiation Therapy Safe?
 Many advances have been made in the field
to ensure it remains safe and effective.
 Multiple healthcare professionals develop
and review the treatment plan to ensure that
the target area is receiving the dose of
radiation needed.
 The treatment plan and equipment are
constantly checked to ensure proper
treatment is being given.

49. Cancer cervix conventional

50. Cancer cervix IMRT

51. Cancer Left Breast RAPIDARC

52. Cancer lung conventional

53. Cancer lung Rapid arc

54. Cancer Pancreas Rapid ARC

55. Cancer of GE Junction IMRT

56. Cancer tonsil IMRT

57. Cancer Nasopharynx IMRT

58. Recurrent GBM(SBRT) 25Gy/5#

59. Metastatic Ca. Ovary (SBRT)
SBRT to Single Metastatic Lesion In Brain (30 Gy/5#)

60. Summary
 Radiation therapy is a well established modality for the
treatment of numerous malignancies
 Radiation oncologists are specialists trained to treat
cancer with a variety of forms of radiation
 Treatment delivery is safe, quick and painless

61. THANK YOU