An Evolution in the Use of Radiation

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Isolated spinal relapse (what would be prevented by CSI)

Other sites inside and outside CNS

Slide 22

Radiotherapy dose and volume

343 patients received CSI

LC achieved in all but one patient (99.7%)

4 (1.2%) had isolated spinal relapses

13 (3.8%) overall relapse over half outside craniospinal axis.

Local relapse rate 0.3%

278 patients treated with whole brain or whole ventricular

LC 97.5%

8 (2.9%) had isolated spinal relapse

21 (7.6%) overall relapse

Local relapse rate 2.5%

133 focal radiotherapy

LC 93.5%

15 (11.3%) had isolated spinal relapse

31 (23.3%) overall relapse rate

Local relapse rate 6.8%

Slide 23

Radiation and Chemotherapy

SIOP experience reported on chemotherapy + focal radiotherapy associated with a 10% excess risk of relapse in the ventricular area when compared to craniospinal radiotherapy

US phase II study reported on patients with localized or metastatic germinomas.

Treated with 4 cycles of etoposide and cisplatin,

Local disease treated with focal RT to prechemo volume + 2 cm margin with dose stratification based on response.

All but one remained in complete remission

Phase II study reported by Matsutani et al 84% of patient with localized germinoma’s achieved a CR after induction chemotherapy

All received 24 Gy to a field including the third and lateral ventricles.

12.2% relapse rate at 2.9 years

77% were out of field.

Slide 24

COG ACNS0232

Phase III study comparing radiotherapy alone vs chemotherapy followed by Response-based Radiotherapy for Newly diagnosed primary CNS Germinoma

Stratification

Local (M0)

Occult multifocal (Modified M+) DI, M0 patients on Regimen B with significant reduction in “normal” pineal gland or pituitary stalk

Disseminated (M+) (Patient MN)

Slide 25

COG ACNS0232

Regimen A

Standard Radiotherapy

Slide 26

COG ACNS0232

Regimen B

Chemotherapy and Radiotherapy

Slide 27

Implications

Radiotherapy alone for Germinomas can achieve high long-term rates >90%

Reduction in field size without additional therapy can achieve good local control rates in localized disease

Chemotherapy may be able to help reduce failure rates so patient can receive reduced dose and field radiation.

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Acknowledgements