Presented at Panel Discussion during IFOS 2013

1. Role of RT in Oropharynx Cancer:
Optimal Techniques and Dose Schedules in
Multi-modality Environment
Yong Chan Ahn, MD, PhD
Dept of Radiation Oncology
Samsung Medical Center
Sungkyunkwan University School of Medicine

2. HNC Management
• Multidisciplinary approach:
- Surgeons
- Radiation oncologists
- Medical oncologists
- Clinical nurse specialists
- Speech and language specialists
- Dieticians

3. What’s Up in Head/Neck Oncology?

4. Cancer 2008

5. Paradigm Shift in Surgery
Standardized terminology in neck dissection:
- Crile (1906): En bloc dissection of cervical lymphatics
- Martin (1951): Radical ND
- Suarez (1963): Modified radical ND
- Gould (1960): Sentinel LN biopsy
- Frazell (1962): Elective ND
- Lindberg (1972): Selective ND
Organ preservation
Reconstruction

6. Paradigm Shift in Chemotherapy
• Induction (neoadjuvant) chemotherapy
• Adjuvant chemotherapy
• Salvage/palliative chemotherapy
• Concurrent chemotherapy with RT
– Definitive
– Adjuvant
• Role of targeted therapy?

7. RT alone in early stages
• High dose RT alone (60~70 Gy):
– High cure rate (70~90%) in exophytic small
tumors (T1-2) limited to mucosa
• External RT is crucial Tx option in early
stage.

8. CCRT in advanced stages
• High dose RT alone (70 Gy):
– Loco-regional failure in >30~50%
– Ultimate 30% 5-year survival rate.
• Concurrent chemo-RT is better.
– To increase loco-regional control
– To reduce incidence of distant metastases

9. Which RT technique should be considered?

10. 2D
3D
IMRT

11. NEJM 2012

12. < 30
years

13. Which RT technique should be considered?
• Outcome with IMRT is limited and follow-up is
relatively short.
– Loco-regional control: comparable to 3D CRT
– Late toxicities (xerostomia): lower than 3D CRT
• 3D CRT remains minimal standard of RT
technique but, whenever possible, IMRT
should be implemented.

14. Treatment Policy (NCCN Guideline)

22. How I Do?

23. Definition Description
GTV Palpable or visible
disease
Physical examination, radiographs
CTV GTV + expansion for
microscopic spread
Knowledge of patterns of spread (onco-
anatomy)
PTV CTV + expansion for
setup error and organ
motion
Imaging studies (fluoroscopy or 4D CT to
define degree of motion) and reproducibility/
stability of mobilization/localization systems

24. Strategies for shrinking tumor:
• Shrinking field by 3D-CRT
• Dose painting by IMRT
• Both

25. Dose Schedules at SMC
3D RT TomoTherapy
Main concept Serial shrinking field Dose painting
Subclinical disease 36 Gy/18 Fx’s 36 Gy/18 Fx’s 36 Gy/18 Fx’s
Equivocal lesion 54 Gy/27 Fx’s
60~63.6 Gy/Fx’s
(2*30 or 2.2*18 + 2*12)
Definite lesion 70 Gy/35 Fx’s
66 Gy/30 Fx’s
(2.2*30)
69.4 Gy/30 Fx’s
(2.2*18 + 2.4*12)
Number plans 3 times 2 times
Duration 7 weeks 6 weeks
>50% before Jul 2011 100% since Jul 2011

26. Has It Worked Well?

27. CCRT is comparable to S+RT
• 237 patients with stage III/IV oropharynx ca were
treated at SMC (Jan ’98~Dec ’07)
• Matched-pair analysis
CCRT
(N=65)
S+RT
(N=65)
P value
3Y OS 80.9% 67.9% 0.096
1Y PFS 85.1% 88.5% 0.469
Abstract at ACOS 2012

28. Relevant Data from SMC
Patients Remarks Outcomes
1 83 patients
tonsil ca
’04/Jan~’10/June
mostly III/IV receiving CCRT
TLG: significant on OS
89.9% alive
@ median 25.7 Mo
2 59 patients
oropharynx ca
’06/Mar~’10/Oct
mostly III/IV receiving CCRT
TVRR: significant on LRC
3 Yr OS = 92.7%,
3 Yr PFS = 82.7%,
3 Yr LRC = 86.2%
1. Moon SH et al. (Head Neck, 2013)
Prognostic value of 18F-FDG PET/CT in patients with squamous cell carcinoma of
the tonsil: Comparisons of volume-based metabolic parameters
2. Lee H et al. (Head Neck, in press)
Tumor volume reduction rate measured during adaptive definitive radiation therapy
as a potential prognosticator of locoregional control in patients with oropharynx
cancer

29. Summary or Personal Bias?
• For early stage disease, RT alone may be
sufficient.
• For loco-regionally advanced disease, CCRT
should be considered first (whenever possible).
– Satisfactory clinical outcomes (LC, DFS and OS)
without compromising functional impairment.
– Little confusion in target delineation as in induction
chemo.

30. Potential pathologic outcomes
following induction CTx
To irradiate or not? Where to/How to irradiate?
Confusion often leads to improper target
delineation, Tx failure, and side effects.

31. Future Perspectives
• Refinement of imaging modality is required.
• De-intensification strategy based on prognostic
factors may be considered.
– Reduced dose RT following TORS?
– RT concurrent with target agent +/- chemotherapy?

32. Often times, it is very difficult to tell
where the seashore exactly is…
Thank you your attention!

33. Any Questions?
Feel free to e-mail me at
ahnyc@skku.edu
ycahn.ahn@samsung.com