Discussion
Macroscopic leptomeningeal dissemination at DIPG progression has been
reported in up to 30% of cases. 10-13
However, the real number is probably underestimated because a high
proportion of patients at the end of life are not imaged and/or do not
undergo an autopsy. Furthermore, when histologically studied,
microscopic disease dissemination has been found in a greater
proportion. Caretti et al examined autopsy material from 16 DIPG
patients and observed subventricular dissemination in 63% of the
patients. Consequently, the real overall incidence of at distance
dissemination is not well established, but likely higher than
reported.5,12,14
ReRT, although palliative, has shown to be a good salvage in a number of
contexts (i.e. relapsed HGG, ependymoma) given its reasonable
tolerance and clinical/radiologic
benefit.1.7Fontanilla et alreported 6 patients treated with focal reRT (20Gy) at recurrence for the
first time in 2012.2 Since then, several groups have
reported similar positive experiences.3,151.Recently, Lu et al reported a meta-analysis
on this topic reinforcing the role of palliative focal reRT specifically
for DIPG.16 In patients with DIPG, focal progression
is usually the rule and is responsible for most of the neurologic
symptoms and ultimate clinical deterioration, reinforcing the use of
focal reRT. Our case is singular because the patient presented
metastatic asymptomatic progression. However, and as in other DIPG cases
without dissemination, with further tumor growth he developed brainstem
symptomatology. Given the presence of other tumoral lesions and the good
initial disease response to upfront irradiation, we opted to administer
CSI, being our goal to control both disease compartments (local and
leptomeningeal). Fortunately our approach was very well tolerated,
proved clinical and radiological response, extending his survival for 6
months. Of note, quality of life was remarkably good with no need for
admissions and with good functionality until his last days.
Based on this experience, we conclude that until new and effective
therapies are identified, CSI could be a safe and good palliative reRT
strategy for patients with progressed disseminated DIPG.
Conflicts of interest: The authors declare no conflicts
of interest