Dr. Rico Liu discusses the effects of radiation therapy and the role of new technologies in treating primary central nervous system lymphoma (PCNSL). Radiotherapy alone provides a median survival of 12 months for PCNSL patients, while chemotherapy followed by whole brain radiotherapy increases median survival to 48 months. The combination of chemotherapy and radiotherapy results in a 94% overall response rate for PCNSL patients, though 15% experience severe delayed neurotoxicity, especially elderly patients. New technologies and lower consolidation radiation doses may help reduce the risk of delayed neurotoxicity. Radiotherapy remains effective for patients unable to receive chemotherapy.

1. Dr. Rico Liu
Consultant, Department of Clinical Oncology, Queen Mary Hospital
Honorary Clinical Associate Professor, Department of Clinical Oncology, The University of Hong Kong
Deputy Hospital Chief Executive, Queen Mary Hospital
BTG 2013 Feb 2013

2. Points for discussion
Effects of radiation
Radiotherapy is not for everyone but for whom and
when
The role of new technology

3. Effects of radiation
External Radiotherapy
•High energy Xray
• Photon-
•Gama ray- from radioactive decay, e.g. Colbert
•High energy particles
• Electron
• Proton
Brachytherapy
Systemic radiotherapy
apoptosis

4. Effects of therapeutic radiation

5. Normal tissue tolerance
Milano et al., Semin Radiat Oncol. 17 (2007): 131-140

6. Treatment improves survival
Median survival (mo)
Untreated ~2
WBRT alone ~12
Chemotherapy follows
by WBRT
~ 48
Henry JM et al. Cancer 34: 1293, 1974
Nelson DF et al. IJROBP Volume 23, Issue 1, 1992, Pages 9–17
Ferreri AJ et al. Ann Oncol. 2000 Aug;11(8):927-37

7. PCNSL: Radiotherapy alone
RTOG 8315
Phase II study of WBRT 40Gy + 20Gy boost
N = 41
Overall median survival 12.2 months
Benefit of boost doubtful: disease recurrence
frequently occurred in the boosted field, survival no
better than previous study without use of boost
Ocular involvement: 36Gy to both eyes (or Rx
with high dose MTX)
Nelson DF et al. IJROBP Volume 23, Issue 1, 1992, Pages 9–17

8. PCNSL: Chemo + radiotherapy
 CR 58%, PR 36% (Overall RR 94%)
 Overall survival 37 months
 15% ( 12 patients) developed severe delayed neurologic toxicity
 8 out of 12 died ( 5/8 from the group > 60 years of age and 3/8 from < 60 years of age)

10. Delayed neurotoxicity is worse for
elderly patients
Omuro AM et al. Arch Neurol. 2005 Oct;62(10):1595-600

12. G-PCNSL-SG-1 trial

13. Not enough evidence to forgo WBRT
Limitations of the trial
Low statistical power
High protocol violations
High rate of lost to follow up
Small sample size in the analysis of neurotoxicity

14. Lower dose of RT for patients with CR

15. WBRT- set up

16. Therapeutic management of PCNSL
Ferreri A J M Blood 2011;118:510-522Role of radiotherapy

20. The role of new technology
Neuro Oncol (August 2009) 11 (4): 423-429

21. Summary
PCNSL is rare
Chemotherapy +/- radiotherapy offer the best
survival
Delayed neurotoxicity is common and can cause
major disability and death
Reduce risk of delayed neurotoxicity
lower consolidation dose for patients <60
defer WBRT for those older patients >60
Radiotherapy remains an effective treatment for
patients considered not suitable for chemotherapy

22. Thank You