2. RADIATION THERAPY in pediatric BONE TUMORS
Dr M.Tabatabaeefar
Radiation oncologist
Shahid Beheshty Uni.
Imam Hosain Hospital
Tehran IRAN

3. INTRODUCTION Primary bone tumors are rare malignancies.
(6 percent of all childhood cancers)
Most common amongst them are :
Osteosarcoma
Ewing’s sarcoma

5. OSTEOSARCOMAS

6. Osteosarcomas are highly radio resistant tumors
The management basically comprises of surgery and chemotherapy.
Standard of care is neo adjuvant chemotherapy followed by limb conserving surgery

7. Radiotherapy has been reported to improve local control of borderline or unresectable extremity osteosarcoma, vertebral osteosarcoma and pelvic osteosarcoma.
It has also been used to treat osteosarcomas of the mandible.

8. INDICATIONS FOR RT IN OSTEOSARCOMA
Definitive : Unresectable disease
Patients who refuse surgery/medically inoperable
Sites not amenable for surgery :
Pelvis
vertebral
Jaw
Margin positive disease after surgery
(Close margins after surgery)
Palliation

10. RADIATION THERAPY TECHNIQUES
Patient positioning and immobilization :
Depends on the site to be treated
Immobilization should be done adequately so that the fields are adequately reproducible.
The lesion should be positioned such that the entrance and exit of the beam(s) do not expose contralateral limbs or other tissues unnecessarily.

11. Fields and borders : Dosage : Axial : 2 cms margin
Extremity : 4-5 cms margin
Strip of skin to be spared to prevent lymphoedema
To restrict fields at anatomical barriers
Dosage :
60 Gy in 30 # for microscopically involved margins
66 Gy in 33 # for macroscopic disease
70 Gy in 35 # for inoperable disease
From initial tumor dimensions on the pre operative imaging

12. AVAILABLE TECHNIQUES OTHER Techniques :
3D Conformal Radiation therapy
IMRT
Proton beam therapy
OTHER Techniques :
Extracorporeal and Intraoperative RT :
The extracorporeal technique includes en bloc resection of the tumor and surrounding soft tissues, irradiation of the specimen, and reimplantation, often with the aid of prostheses.
In IORT, the operative field is exposed and radiotherapy is administered. No resection of the tumor is performed.

13. Palliative : Palliative RT for pain management
In cases of big lesion causing mass effects
Rhenium, Strantium, Samarium 153
Whole lung irradiation :
EORTC-20781/SIOP-3 phase 3 trial
240 P to 3 arms:
ChT, WLI (20 Gy), ChT & WLI
DFS & OS: NO Diff
with the recognition of the other advantages of systemic therapy, prophylactic lung irradiation has fallen out of favour.

14. Ewing sarcoma

15. history
Historically, RT was preferred over surgery because of less acute morbidity, acceptable rates of local control (50 to 77 percent), and poor long-term prognosis, largely due to distant dissemination in the absence of effective chemotherapy

16. Ewing sarcoma family are a radio sensitive tumor
The management basically comprises of surgery and /or RT and chemotherapy.
Standard of care is neo adjuvant chemotherapy followed by surgery and /or RT and then chemotherapy.

17. Contemporary treatment
Contemporary treatment guidelines emphasize surgical resection as the local control modality of choice if it is believed that :
The lesion can be resected with negative margins,
Without excessively morbidity
With the expectation of a reasonable functional result

18. Surgery is preferred for potentially resectable lesions
It avoids the risk of secondary radiation-induced sarcomas
In the skeletally immature child, resection may be associated with less morbidity than radiation

19. In many retrospective series, rates of local control and survival are superior after surgery compared to RT alone ,However, larger cooperative group studies have failed to reflect this advantage, and selection bias likely accounts for at least some of these results. Smaller, more favorably situated peripheral tumors are more often resected while larger, axial lesions are referred for RT.

20. INDICATIONS FOR RT IN Ewing Sarcoma
Definitive : Unresectable disease
Patients who refuse surgery/medically inoperable
OR ,Sites are not amenable for surgery :
Pelvis
Vertebral
Preop RT: marginally resectable tumore
Post op RT :Margin positive disease after surgery
(Close margins after surgery)
Palliation

21. Definitive RT 12 week VAC/IE then,45Gy to PTV +GTV boost
(55.8 Gy to post CHT GTV in responsive and Gy in non responsive )

22. Preop RT
36 to 45 Gy to GTV + 2 cm margin

23. Post Op RT
RT should begin within 60 days of surgery and concurrently with CHT
R0 resection : poor CHT response , 45Gy
R1 resection : 45 Gy
R2 resection : 45Gy boost

24. RT FOR METASTATIC DISEASE
Management of the primary site 
it may be difficult to justify a large resection of the primary site because of the poor long-term prognosis
Start early or late ?

25. Metastatic disease rt Boost?? Whole lung RT (Post CHT /Metastasectomy)
15 Gy /10 F for patients less than 14 years old
18 Gy /10 F for patients more than 14 years old
(current study ,below or above 6 years ,12 vs 15 Gy )
Boost??

26. CONCLUSIONS
TEAM WORK

27. The role of radiation therapy in the management of bone tumors depends on the histology of the tumor and the resectability.
Surgery forms the mainstay of management of most of the tumors of the bone.
However, radiation therapy has a significant role to play in inoperable or incompletely excised tumors for adequate local contol.

28. The newer modalities of delivering radiation therapy and “tailored field” radiation therapy approach has led to significant decrease in the toxicity.
The toxicities are also contributed by the chemotherapy used for the treatment of the tumor and cumulative effect of both should be considered while planning a treatment.

29. SEQUELAE OF TREATMENT Acute effects
Desquamation of the skin,
myelosuppression,
mucositis, diarrhea, nausea, and cystitis.
Patients receiving whole lung irradiation are at risk for radiation pneumonitis.
Acute reactions are usually self-limited and subside within 10 to 14 days of RT completion

30. Late effects Arrest of bone growth Soft tissue induration and fibrosis
pathologic fractures

31. arrest of bone growth
Younger, prepubertal children are at greatest risk for radiation-induced arrest of bone growth.
Sparing of uninvolved epiphyseal plates minimizes limb shortening after RT of extremity lesions.

32. soft tissue induration and fibrosis
RT doses above 60 Gy are associated with markedly increased rates of soft tissue induration and fibrosis
High-dose circumferential irradiation of an extremity is associated with edema, fibrosis, and compromised limb function .
This can be avoided by sparing of an adequate strip of tissue

33. pathologic fractures
Weight-bearing bones are at risk for pathologic fractures. The highest risk is within the first 18 months of RT completion.

34. Second malignancy after RT
With protocols utilizing lower doses of RT and tailored RT fields suggest that the magnitude of the risk is somewhat lower.

35. Any Questions?

36. Thank you...