Can the inguinal and pelvic nodal RT be omitted for FIGO IVA unresectable vulvar cancer with a negative bilateral inguinal nodal dissection?  

In my opinion, the answer is a qualified "yes." Has the patient had a PET scan that is negative, except for the primary vulvar lesion? If so, this argues in favor of omitting inguinal and pelvic LN's since the negative predictive value of PET for adenopathy in gyn cancers is consistently reported to...

FIGO Stage IVA can either be N3 disease (not the case here given pN0) or T3, suggesting potential invasion into the rectum, bladder, upper part of the vagina, or upper urethra. It can also signify invasion into the pelvic bone. While the patient did have a bilateral inguinal dissection, pelvic lymp...

I completely agree, especially since she had a negative groin dissection.  The incidence of lymphedema after both a groin dissection and postoperative radiotherapy is very high and can be debilitating.