Rhabdo HW Flashcards
How is Rhabdomyosarcoma treatment tailored?
Staging + grouping = Risk stratification
Staging: Imaging + PE -Location (fav/unfav) -Suspected LN (unfav only) -Size (<5 cm vs > 5 cm, for unfav only)
Grouping (intraop / path findings) R0 R1 or R0 N+ R2 Mets
Grouping can only be changed pre chemo, ie after a PRE (pre-treatment re-excision PRE)
Do a PRE if you think you can resesect fully (with minimal morbidity) before chemo
Site of RMS mets
Lung Brain Liver Bone Bone marrow distant muscle nodes
includes malignant pleural effusion + ascites
What is the standard chemotherapy?
VAC / VI
Vincristine
Actinomycine(Adriamycine=Doxorubicine in NB)
Cyclophosphamide
Irinotecan (not given in NB)
When / Why to perform a Delayed primary excision DPE
After chemo (12 weeks) Pathologic response has a direct association with prognosis
Consider if residual tumor post chemo and if a complete resection can be achieved without significant morbidity.
May reduce radiotherapy dosing.
Should lymp node dissection / sampling be performed?
Sampling for prognosis + modification to radiotherapy / chemo in trunk + extremity
trunk / extremities tumor: may use sentinel lymph node
Dissection: In paratesticular rhabdo, sample ipsilateral retroperitoneal dissection up to renal hilum. + supra hilar nodes are considered metastatic.
Emerging data supporting LN sampling in all fusion + ARMS.
Who gets radiotherapy?
Everybody except group 1 ERMS
How to perform a radical orchiectomy + Retroperitoneal lymphnode dissection?
Generous inguinal incision, curved towards scrotum.
Early proximal control of spermatic cord is performed at the level of the internal ring. If transcrotal biopsy was performed, or if skin is thetered, resect hemiscrotum.
Vas is seperated from vessels and double ligation is performed on respective structures.
RPLND follows a dissection template. goal is to dissect lymphnodes but preserve sexual function. to do so, contralateral dissection on aorta starts above IMA. Upper border is renal vein.
On R, lateral edge is the R gonadic vein, medial is the L gonadic vein (iliac vein is followed until the IMA is crossed, and the dissection begins on aorta)
On L side, its the same except the medial plane is the aorto-caval junction
SEE PICTURE
What is the typical treatment for vulva/vagina/uterine RMS?
good prognostic - embryonal or botryoid subtype.
perform biopsy followed by chemo/radiotx. if residual disease, may attempt brachytherapy.
for relapse, can attempt exenteration. poor prognostic.
What immunohistochemical stains are used to identify RMS
desmin
myogenin
What cells does RMS arises from
multipotent mesenchymal cells
What is the age distribution of RMS
bimodal
1-6: mostly ERMS, in head and neck + GU
10-18: Mostly ARMS, trunk + extremities
75% ERMS
What genetic disorder is RMS associated with?
Li-Fraumeni (p53) NF 1 (cafe au lait)
What are histological characteristics of RMS
Rhabdomyoblast at different stage of maturation with mesenchymal background.
What is fusion status?
it is the result of a cytogenetic test (FISH - fluorescence in situ hybridization)
ARMS express a fusion protein arising from the fusion of FOXO and PAX3 or PAX7 proteins. it was observed that prognostic of FOXO-PAX 7 fusion tumor is over all worst.
PAX-FOXO fusion status will likely guide treatment in the future, and not histology
How to plan for surgical resection of chest wall RMS?
5 mm margins. you can ask for frozen section but its unreliable.
take one rib above and below
Indications for neoadjuvant tx:
- 3 or more ribs involve
- tumor bigger than 5 cm,
- scapula, sternum involved
- intraspinal involvment
For DPE with R1/R2 margins, offer radiotherapy.
R1 and R0 have equivalent outcome because RMS is very radiosensitive.
Avoid radiotherapy below 3 yo
