Pediatric RMS Badder n Prostate

Pediatric RMS Badder n Prostate

Suruchi Singh 27 Apr 2011 05:56

the pt 6 yr old boy, with RMS of urinary bladder n prostate,,, at presentation he had large B/L iliac LAP along with huge primary tumor. He responded very well to chemotherapy with disappearance of nodes n residual thickening in bladder bt quite a volume of dis in prostate, but is still inop (as per our surgeons). Hence the kid is being planned for RT, we managed to get him funded for IMRT, but am facing quite a few problems while contouring n planning for this chap.
1. Do we have separate set of constraints for this age gp of pts for organs like rest of bladder, rectum, testes n small bowel.
2.Do we need to treat PA nodes also in this pt.
3. Wat would be constraints for bones in this pt, as most of them are unossified.

Re: Pediatric RMS Badder n Prostate

Santam Chakraborty 27 Apr 2011 14:39

Hi suruchi this article is quite pertinent to your question:
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T7X-50BDHTK-R&_user=7895621&_coverDate=06%2F18%2F2010&_rdoc=1&_fmt=high&_orig=gateway&_origin=gateway&_sort=d&_docanchor=&view=c&_searchStrId=1732781019&_rerunOrigin=scholar.google&_acct=C000073114&_version=1&_urlVersion=0&_userid=7895621&md5=f28c6af56a7bbc1466a747244346739f&searchtype=a
Essentially the recommendation is:

1. Include entire gross disease at the time of presentation.
2. Margin of 2 cm respecting anatomical boundaries ok
3. Gorss nodes needs to be included
4. No need for prophylactic irrradiation

Constaints are not very well defined even for the adult patients - however as this study shows that underdosing carries a more severe risk of failure - I would concentrate more on getting the coverage and dose correct rather than thinking about normal organ constraints. Testicular shielding can be implemented but rest of the organs especially small bowel and rectum will get treated. Bladder I would not consider sparing at all.

Bones again are difficult point doses of 25 -35 Gy can be suggested as a cutoff but since you say the initial tumor was large it would be exceptionally difficult to achieve. As it is without surgery this patient is not receiving the optimal treatment. I found this reference where they modelled the effects of RT on bone growth
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T7X-4G0HV9J-3&_user=7895621&_coverDate=08%2F01%2F2005&_rdoc=1&_fmt=high&_orig=gateway&_origin=gateway&_sort=d&_docanchor=&view=c&_rerunOrigin=scholar.google&_acct=C000073114&_version=1&_urlVersion=0&_userid=7895621&md5=9b7dc2b6e489447aa54ff3ffb3437938&searchtype=a

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Re: Pediatric RMS Badder n Prostate

Nikhilesh Patil 28 Apr 2011 03:33

Tough case to treat. Dont have anything else to add to Santam's comment.