Radiotherapy (SIOPEN)


(Alexey) #1

Hello,

I just wanted to ask other parents if they know how much of radiotherapy (in our case this is a proton radiotherapy) brings to the overall success. I fully understand that in our case (HRNB, MYC amplified) we do not have a choice, but anyway are you aware about any official point of view about it. If you can provide a link to any serious researches then it would be great!

We asked our doctor, but he just said that it improves overall outcome, but didn’t provide any details yet…

Thanks

Alexey


(Sam Saffron) #2

I saw this talk mentioned in ANR this year:

http://anr-2016.p.asnevents.com.au/days/2016-06-20/abstract/32857

Methods: The aim of this analysis was 1) to investigate local control and event-free survival (EFS) in the full cohort of 1467 patients (stage 4: 1180, MNA: 170, unknown: 117) having received irradiation according to the HR-NBL1/SIOPEN trial recommendation after high dose chemotherapy and autologous stem cell reinfusion between 2002-2015. 2) to correlate local control with RTQA in the subset of 100 patients with previously performed RTQA. Results: In the group of 1467 patients no difference was detected neither in the cumulative incidence of local relapse nor in event-free survival between patients receiving < 21Gy, 21Gy as prescribed or > 21Gy. However, only in the subgroup of 170 patients with localized MNA disease a trend towards improved 5-year EFS was observed in patients receiving 21Gy as prescribed in contrast to those patients who did not (5yr-EFS:70% versus 62%). In the subset of 100 patients with previous RTQA a significantly increased local recurrence rate of 44% (10/23pts) was found when RT had not been delivered according to protocol in contrast to 22% (17/77pts) in patients treated with correct volume and dose (p=0,042). Conclusion: These early results show the importance of RTQA for local control in the treatment of neuroblastoma. Further confirmation in a larger patient population is currently being performed. Prospective central validation of RT planning prior to RT delivery could improve overall disease control.

There is very little literature out there about proton therapy benefits for NB, however this is what MSKCC use, as a parent it is really terrible to hear that your child is going to be 4.5cm shorter due to this treatment, proton therapy will decrease the amount of spine radiation which in turn means less height is lost.

MSKCC recently moved to 18Gy from 21Gy in some cases, there is a published paper about this perhaps discuss it with your radiotherapy consultant. Keep in mind odds of anyone straying from protocol on SIOPEN approach zero, and honestly you don’t really want to taking on the responsibility of experimenting in this department.

There have been quite a few papers over the years highlighting the importance of radiotherapy during HRNB treatment, it is considered a very important aspect of the treatment. There is this old COG study that many would refer to.


(Alexey) #3

Great! Many thanks, Sam!


(Alexey) #4

Do you know from where this number came from? May be this is for a full body irradiation treatment which is not an option anymore?


(Sam Saffron) #5

It depends on how many vertebras get radiated (note we did traditional radiotherapy not proton). The guideline we got is that you lose 0 - 1cm of growth per vertebra for a 3 year old. (for the lower vertebras)


(Sam Saffron) #6

@Alex note, I corrected my number above, be sure to consult your radiation therapist for an accurate estimate, it totally depends on the location and size of tumor before surgery after induction chemo (in SIOPEN protocol)


(Alexey) #7

Thanks, @sam
Anyway this new figure is less scared than before…


(Sam Saffron) #8

I came across this recent paper today:

http://www.redjournal.org/article/S0360-3016(16)30276-0/abstract

After intensive chemotherapy and maximal surgical debulking, hyperfractionated RT with 21 Gy in high-risk neuroblastoma results in excellent local control. Given the young patient age, concern for late effects, and local control >90%, dose reduction may be appropriate for patients without MYCN amplification who achieve GTR.

It appears that the recommendation to reduce to 18 Gy by the doctors at MSKCC is mainly for non MYCN amplified cases.


(Kristen Wilson Mitchell) #9

We are currently doing radio for addison and we were told to expect her seated hight to be reduced by about 2 to 2.5 cms shorter she is 3 yrs old.


(Parker Moss) #10

What part of the body are they planning on using proton therapy? Although there is no evidence that proton therapy has equivalent efficacy to IMRT (focused) radiotherapy, it definitely does less collateral damage - though this is only relevant in some parts of the body and not others (hence my question). Also, not all proton machines are the same and collateral damage differs by machine type so look into this.


(Alexey) #11

On the main tumor side - above one of the kidneys. In therms of efficiency, the doctor said something about 1.1 coefficient which means its 10% more efficient than a photon therapy and as result they can respectively reduce the dose.
So anyway we have started already and will hope for the best…