role and risk of radiation in management

1. Role and risk of radiation in
management of post operative
patient
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2. Outline
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 Introduction
 Biological aspects of radiation
 Role of PORT
 Risks of PORT
 References

3. Introduction
 Head and neck cancers are very common
 Contributing to approx. 30% in Male and 13% in
female cancer burden ( Vendan Murphy etal)
 Nearly 60% of patients present with locally advanced
disease
 Surgery +/- RT are curative in 80-90% of stage I & II
 Outcomes in stage III & IV are less promising
requiring (surgery + Chemo RT) according to a study
by Tupchong L
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4. Rationale of PORT
 The addition of PORT became an accepted
concept following the publication of results
from
1) MD Anderson Cancer Center (MDACC)
2) The Radiation Therapy Oncology Group
( WHICH DEMONSTRATED THAT ADJUVANT RT
DECREASED RECURRENCE AND IMPROVE
SURVIVAL RATE )
 Following PORT, locoregional control is 69%-
72%, and 5-year survival rates approach 30%-
40%
 Surgery is the preferred initial treatment
followed by adjuvant chemo/ radiation therapy
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5. Rationale of PORT
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Despite all mgt the 5yr survival rate is less
than. 50%(sub optimal LRC)
Local regional failure contributes pre
dominantly to recurrence and death
LRC of H&N malignancies is important as
salvage of LRD is difficult

6. Biological aspects of
radiotherapy
Ionizing radiations are divided into the
corpuscular and electromagnetic
Corpuscular radiations are represented by
electrons, protons and neutrons;
 Electromagnetic radiations are called photons(
X rays and by gamma rays).
Most radiotherapy treatments are done through
the use of photons 5/29/2023
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7. Ionizing radiations act on the nuclear DNA
leading to death or loss of its reproductive
capacity during mitosis
Cells with a high degree of mitotic activity
are more radiosensitive than those with low
mitotic rate.
There is a radio sensitivity scale both for
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8. Mechanism of action
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 Radiation action can be DIRECT or INDIRECT.
 On the direct action, the DNA molecule is cleaved,
interfering in the duplication process.
 On the indirect effect, water is dissociated into its two
elements, H+ and OH; the latter reacts with the basis
of DNA, interfering in the duplication process.

9. Biological aspects of radiotherapy
cont..
Due to the fact of being in a continuous
multiplying process malignant cells can suffer the
radiation effects
Embryonicmalignancies&lymphomas(most
radiosensitive)
Epithelia tumors eg. Carcinomas are moderately
radiosensitive.
Less sensitive ones are osteosarcoma and
malignant melanoma
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10. FACTORS AFFECTING RADIOSENSITIVITY
OF A TUMOR
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 Histology type
 oxygen concentation ( radiosensitivity decrease in
hypoxic state)
 Cell cycle( high in M phase and low in S phase)
 Cancer related genes p53, VEGF etc.

11. Radiation dosage units
 Rad (radiation absorbed dose) was initially
proposed, (difference between the applied
radiation and that which went through
tissues)
 Recently, this unit was replaced by Gray(
defined as 1 joule per kilogram)
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12. Timing of PORT
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When PORT is delivered without
chemotherapy, the combination of SURGICAL
resection and PORT should be considered as
a treatment package.
Completion of the treatment package in as
short a time as possible has been associated
with improved locoregional control and
survival rates, which are likely related to
tumor repopulation effects. (MDACC

13.  RT can be used as primary therapy for small (T1, T2)
tumors of the oral cavity.
 Oral tongue
 Floor of Mouth
 Lip
 Best results are with a combination of external beam
radiation and brachytherapy ( increases LRC (70%-
93%), Chao KS etal 5/29/2023
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14. INDICATIONS OF POSTOP RT?
Definite Indications:
1) Positive Margins ( controversial sometimes)
2) Multiple Nodes
3) Extracapsular Extension
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15. INDICATIONS OF POSTOP RT
Less certain indications:
1)Lymphovascular space invasion 2)
Perineural spread
3) Single encapsulated node +
4) Thick tumors (Tumors 3-9 mm: 44% node+, 7%
local recurrence; >9 mm:
53% subclinical node+, 24% local recurrence
Head Neck 2002: 24:513-20)
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16. Postoperative Radiation for Oral Cavity
Squamous Cell Cancer
According to MDACC study
 Improved locoregional control in postoperative
RT arm (65%) vs. preop RT (48%, p=0.04)
 Trend toward improved survival: 38% vs 33%,
p=0.10)
 Surgical and radiation therapy complications
“similar”.
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17. Risks
MUCOSITIS
 Mucositis is defined as a mucosal irritation.
 Mucositis is believed to occur in four stages
(inflammatory/vascular, epithelial,
ulcerative/bacteriologic and healing).
 WHO classifies mucositis into four degrees.
 Most patients will complain of pain which intensifies
when eating
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18. Candidosis
 Radiated patients are more prone to developing oral
infections caused by fungi and bacterias.(mucosal
colonization of up to 93% Silverman S Jr, etal)
 Oral candidosis is a common infection in patients being
treated for upper airways and digestive tract
malignancies.(17-23%) Ramirez-Amador et al.(43%)
 Patients complain more of pain and / or burning
sensation.
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19. Dysgeusia
 Taste buds are radiosensitive, hence the degeneration
of their normal histological architecture occur
 increase of salivary flow viscosity and the saliva
biochemical alteration creates a mechanical barrier of
saliva which makes it difficult the physical contact
between the tongue and foodstuff
 Normal tasting return around 60 to 120 days post
radiation. cessation
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20. Radiation caries
 The mainly due to decrease of saliva amount
and its qualitative alterations
 Besides, radiation has a direct effect on teeth,
making them more susceptible to decalcification.
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21. Osteoradionecrosis
 Bone ischemic necrosis caused by radiation
bone cells and its vascularization suffer
irreversible injuries
 One of the most serious consequences of
radiotherapy causing pain secondary to
substantial loss of bone structure
.ORN may also result in edema, suppuration
and pathological fractures 5/29/2023
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22. Others
Soft tissue necrosis
Xerostomia (dry mouth)
Imapared wound healing
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23. References
1. William M. Mendenhall etal ; Postoperative Radiotherapy for Squamous Cell
Carcinoma of the Head and Neck
2. Akihiro SAKAI1 etal; statistical Analysis of Post-operative complications after
head and neck surgery
3. Bruno Correia Jham etal; Oral complications of radiotherapy in the head and
neck
4. Chao KS, Emami B, Akhileswaran R, Simpson J, Spector G, Sessions D. The
impact of surgical margin status
5. and use of an interstitial implant on T1, T2 oral tongue cancers after surgery.
Int J Radiat Oncol Biol Phys.1996;36(5):1039-1043.
6. Beitler JJ, Smith RV, Silver CE, et al. Close or positive margins after surgical
resection for the head and neck cancer patient: the addition of brachytherapy
improves local control. Int J Radiat Oncol Biol Phys. 1998;40(2):313-317.
7. Fujita M, Hirokawa Y, Kashiwado K, et al. Interstitial brachytherapy for stage I
and II squamous cell carcinoma of the oral tongue: factors influencing local
control and soft tissue complications. Int J Radiat Oncol Biol Phys.
1999;44(4):767-775.
8. Bachaud JM, Cohen-Jonathan E, Alzieu C, David JM, Serrano E, Daly-
Schveitzer N. Combined postoperative radiotherapy and weekly cisplatin
infusion for locally advanced head and neck carcinoma: final report of a
randomized trial. Int J Radiat Oncol Biol Phys. 1996;36(5):999-1004.
9. www.elearning
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