A discussion on the radiotherapy to oral cancer

1. ROLE OF RADIOTHERAPY IN
MANAGEMENT OF ORAL
CANCER
PRESENTED BY: SAILESH KUMAR. R
PG TRAINEE ( DEPT. OF OMFS)

2. Radiotherapy is one of the most common treatments for
cancer.
It is the use of ionising radiations in the treatment of
malignant and benign conditions.
Aim is to deliver tumoricidal doses to the disease, limit dose
to surrounding normal structure to tolerance.

3.  What does radiation therapy does to the body?
 When to refer for radiotherapy in oral cancer patients?
 What are the various techniques to provide radiotherapy?
 What are the complications of radiotherapy and how to avoid/manage
them ?
 What are the advances in radiotherapy?

4. Radiobiology M
(Mitotic
Phase)
G1
(1st Gap/
Growth
phase)
S
(Synthesis
Phase)
G2
(2nd Gap/
Growth Phase)
Cells shows different
sensitivity to
radiation at different
stages of cell cycle
Most Radiosensitive
Most Radioresistant
Radiation

6. Fractionation strategies
 To use an ↑ed no of smaller doses per fraction than conventional
(1.8 - 2.0 Gy per day) thereby improving the therapeutic ratio
between normal tissues and tumors
 To lessen late normal tissue effects, thus allowing the safe ↑ of
approx 10 - 15% in total dose
 This results in a net gain in overall tumor cell killing over a
standard once daily schedule

7. 4 R s’ in RADIOTHERAPY
(a) Repair of sublethal cellular damage (of normal cells)
(b) Redistribution of tumor cells from radio-resistant (late S phase) into radio-
sensitive (G2-M) portions of the cell cycle
(c) Reoxygenation of the hypoxic portions of tumors (to become radio sensitive)
(d) Repopulation - migration of normal cells into irradiated areas to repopulate
these normal tissues with healthy cells.

8.  Goal  To improve the therapeutic ratio by maximizing the tumoricidal
effect and minimizing acute & late toxicities while using readily available
low LET radiation.
 Three major categories of altered fractionation schemes are :-
1) Hyperfractionation,
2) Accelerated fractionation, &
3) Hypofractionation

10. Rationale : Counteracts adverse effects of tumor cell
repopulation by decreasing over all treatment time
Primary objective here is to diminish deleterious effects of
tumor cell proliferation during course of radiation therapy

11. Indications for Radiotherapy
 Stage I / II disease - Single modality ( Surgery or RT
)
 Stage III / IV disease – Combined modality *Surgery
+ RT (in most patients)
*Chemotherapy + RT in selected patients

12. Primary RT only
 In early stage disease to avoid anticipated functional and cosmetic defect,
 For unresectable disease,
 For high operative risk patients due to comorbidity or poor performance status,
 Recurrent disease when previous multiple surgeries have been undertaken and
further surgery would be technically improbable,
 Patient’s preference
*Shao-Hui Huang et al. Oral cancer: Current role of radiotherapy and chemotherapy. Med Oral Patol Oral Cir Bucal. 2013 Mar 1;18 (2):e233-40

13. Advantages
 No treatment-related delay in surgery, limitations to the dose of
radiation, local and/or regional control
 Allows complete surgical, HP & biological evaluation of the
tumor & LN.
 Reduces tumour bulk, Oxygenation to tissues adequate.
 Lymphatics are blocked by radiation so dissemination of tumour
is less.
 Eliminates microscopic spread beyond palpable tumour mass
Preoperative Radiation Therapy
*Jatin Shah’s , American Cancer Society Atlas of Clinical Oncology - Cancer of the Head and Neck (2001)

14. Disadvantages
a) Delay of surgery by 2.5 to 3 months
b) Scarring and vascular modifications from surgery may
decrease tissue oxygenation and thus adversely affect
radiation tumor cell kill.
c) The radiation dosage may adversely impact on subsequent
postoperative healing

15. Postoperative Radiation Therapy(PORT)
Indications:
Primary tumor factors :-
 Locally advanced T3 or T4 lesions,
 High-grade histology,
 Presence of perineural or vascular invasion,
 Concern with respect to the adequacy of the procedure irrespective
of the histological status of the surgical margins,
 Infiltrating rather than pushing borders of the tumor,
 Positive or close margins of surgical resection
 It is important to emphasize that even with a negative margin status
noted on the pathology report, there is a potential for recurrence of
up to 30 percent
PORT should be initiated within 6
weeks of surgery to maximize the
benefits.
*Jatin Shah’s , American Cancer Society Atlas of Clinical Oncology - Cancer of the Head and Neck (2001)

16. RADICAL & PALLIATIVE RADIOTHERAPY
 Radical RT:- Used for highly radiosensitive tumors such as
sq. cell ca. of the nasopharynx & oropharynx, early-staged
ca.larynx, Basal cell carcinomas & superficial sq. cell ca of
skin.
Radical RT should commence within 4 weeks of the
decision to treat & Palliative RT within 2 weeks.

17.  Palliative RT:- It is an effective means of palliation of symptoms in
patients with incurable HNC.
 USES:-
 1) Control of pain due to tumor shrinkage or necrosis by relieving
pressure on neural structures.
 2) Lesions that obstruct the airway can be palliated effectively when
tumor shrinkage is achieved with RT.
 3) Control of hemorrhage from bleeding tumors
 Dose in the range of 4000 cGy usually is used for palliation.

18. Types of Radiotherapy
BrachytherapyExternal Beam therapy

19. Teletherapy (External Beam Radiation Therapy)
Therapeutic radiation is delivered by two main methods:
(1) Electromagnetic radiation (photons) X-rays and gamma
rays
(2) Particulate radiation in the form of electrons, neutrons,
and protons.
Ionizing radiation deposits energy at a constant rate as it travels
through matter, defined as linear energy transfer (LET).

21. Special ways to deliver external beam
radiation
 Three-dimensional conformal radiation therapy (3D-CRT)
 Intensity modulated radiation therapy (IMRT)
 Image-guided radiation therapy (IGRT)
 Intensity modulated proton therapy (IMPT)
 Stereotactic radiosurgery (SRS) and fractionated
stereotactic radiotherapy
 Intraoperative radiation therapy (IORT)
 Electromagnetic-guided radiation therapy

22. Brachytherapy (Internal radiation therapy)
 The radiation sources are placed either adjacent to the surface of a tumor
mass or bed or inside the tumor itself.
 Applied as a definitive treatment for OSCC; as a complimentary treatment
in combination with surgery
 Types :-a) Interstitial & b)Intra cavitary radiation
 Agents :- Radium, Caesium, Iridium , Radon, Gold, Iodine.

23. Criteria for Brachytherapy
Accessible
<3cm size
Away from bone
(minimum 5mm)
No nodal metastasis

24. FACTORS INFLUENCING THE EFFECTIVENESS
OF RADIOTHERAPY
 Total dose.
 Concurrent treatment with chemotherapy or biological
agents
 Delays in starting treatment Has a relative risk of
loco regional recurrence.

25. Contd.,
 Treatment interruptions Local control falls by 1.4 % per
extra day when it is prolonged.
 Anaemia Hb should be >= 12g/dL. Loss of local control of
disease by approx. 10–15 % for a 2 g/dL fall in Hb.
 Smoking Reduces treatment effectiveness by inhaled CO
displacing oxygen from Hb.

26. Complications HNC radiotherapy
Early
1) Fatigue, hair loss, Radiation sickness.
2) Mucositis, loss of taste, xerostomia.
3) Dryness of mucous membranes.
4) Skin reaction(erythema, dry or wet
desquamation).
5) Candida infection.
6) Haematopoietic suppression.

27. Late
Complications HNC radiotherapy
 Permanent xerostomia.
 Skin changes(atrophy of
skin & fibrosis).
 Decaying of teeth.
 Osteoradionecrosis.
 Trismus, pharyngeal
stenosis
 Transverse myelitis,
carotid artery stenosis.
 Radiation retinopathy,
cataract.
 Hypothyroidism,
hypopitutarisim,
 Radiation induced
malignancy- thyroid cancer,
osteosarcoma of orbit.
 Carotid blowout syndrome.
 Oropharyngocutaneous
fistula.

28. Precautions that has to be taken….
During RT
1) Maintenance of good oral
hygiene.
I. Brushing 2-4 times daily with
soft-bristled brush.
II. Flossing daily, topical fluoride
application with custom trays
III. Frequent saline rinses, lip
moisturizer (non-petroleum
based)
2) Eat balanced & healthy diet.
3) Passive jaw Opening
exercises to reduce trismus
Just After RT
 Complete dental work that was
deferred during radiotherapy
 Maintain integrity of teeth
especially those in radiation
fields
 Frequent follow-up

29. Strategies to decrease dental and oral
complications
 Decrease dry mouth – by using of salivary substitutes
and stimulation
 Decrease dental caries by using of topical fluorides
 Decrease dentoalveolar infection with frequent
evaluation to detect and treat disease promptly
*National Comprehensive Cancer Network (NCCN) guidelines version1.2016, Head and Neck Cancers

30. Contd.,
 Decrease ORN by extracting teeth atleast 2
weeks prior to RT
 Decrease trismus of masticatory muscles by
using custom mouth opening devices to
maintain range of motion
 Need for evaluation during and after treatment
to help minimize complications
*National Comprehensive Cancer Network (NCCN) guidelines version1.2016, Head and Neck Cancers

31.  The use of ill-fitting dentures after radiotherapy also can
increase the risk of ORN. It is probably best not to use lower
dentures after high-dose radiation of 60 cGy (6000 rad) or
more.
 If one has to consider dental extraction after R/T,
 An extraction time less than 6 months after R/T or during the
period of head and neck R/T and
 Extraction tooth number fewer than 5 teeth
 These considerations would significantly lower the ORNJ prevalence.
*Jaw osteoradionecrosis and dental extraction after head and neck radiotherapy: A nationwide population-based retrospective study in Taiwan , Tsu-Jen Kuo et al, Oral Oncology 56
(2016) 71–77
Contd.,

32. What’s new in radiation therapy?....

33. Take Home Message
Proper Diagnosis
with thorough
investigations
Proper
Treatment plan
with better
outcomes
Improve
survival rate of
patients

34. References
 Jatin Shah’s Head and Neck Surgery and Oncology, 4th Edition
 Jatin Shah’s , American Cancer Society Atlas of Clinical Oncology - Cancer of the
Head and Neck (2001)
 Head and Neck Cancer - A Multidisciplinary Approach, Harrison 2009 edition
 National Comprehensive Cancer Network (NCCN) guidelines version1.2016, Head
and Neck Cancers
 Ferguson et al, Advances in Head and Neck Radiotherapy to the Mandible, Oral
Maxillofacial Surg Clin N Am 19 (2007) 553–563
 Ballonof et al, Current Radiation Therapy Management Issues in Oral Cavity
Cancer, Otolaryngol Clin N Am 39 (2006) 365–380
 Shao-Hui Huang et al. Oral cancer: Current role of radiotherapy and chemotherapy.
Med Oral Patol Oral Cir Bucal. 2013 Mar 1;18 (2):e233-40.

35. Acknowledgements
 Prof. Dr. R.S. Neelakandan., HOD Dept of OMFS
 Prof. Dr. Ananthanarayanan
 Dr. Manodh
 Dr. Prabhu Shankar

36. Thank You