Is it necessary to treat pelvic lymph nodes for muscle invasive bladder cancer?

You're correct that there is considerable variability in the target used in bladder radiotherapy. We performed a survey of radiation oncologists regarding bladder cancer radiotherapy patterns and found that ~60% use a "small pelvis," ~30% use a true whole pelvis, and ~10% treat the bladder only [1]. These numbers changed based on the patient's clinical scenario, with bladder only RT preferred for sicker patients.

Truly, the optimal radiotherapy target is not clear. Most RTOG studies utilized a “small pelvis” volume (up to the mid-SI joint), with the goal being to treat the proximal nodes and still allow for creation of a urinary diversion from bowel in the event of requiring a salvage cystectomy. Pathologic studies from patients with ext...

The first I ever read about non-ENI (elective nodal irradiation) bladder RT was Sandler and Montie's experience in the JCO in 2004. They gave 60 Gy whole bladder only; no lymph node RT, no mid-tx cystoscopes, etc. It seemed like a very elegant way to approach things. They reported no LN failures in their small series. Around that time the Germans were also publishing extensively on "straight through" chemoRT for bladder CA (they treated the nodes). Both approaches seemed at odds with the MGH approach (which more or less became the RTOG approach) which was the popular RT orthodoxy of the day. Finally, the Christie published a pretty large series of non-ENI bladder RT... pelvic nodal relapse occurred as the only site of relapse in about 3% of...

Locoregional recurrences are lower compared with DM for Bladder Ca's. I've changed my approach from "treat them all" to select cases (depending the biology of the cancer, CT pelvic findings, etc.) If I don't see cancer in the bladder during the sim or after the first course (in bladder-preservation), and the patient has a "good" bladder with no chronic changes or significant urinary symtomatolgy to begin with, my second phase is the whole bladder.