This is an international phase III trial, with a Bayesian design, incorporating two sequential randomisations. It efficiently examines a series of questions that routinely arise in the sequencing of treatment. The study design has evolved from lengthy international consultation that has enabled us to build consensus over which questions arise from current knowledge and practice. It will enable potential randomisation for the majority of patients with inguinal lymph node metastases and will provide data to inform future clinical decisions.

InPACT-neoadjuvant patients are stratified by disease burden as assessed by radiological criteria. Treatment options are then defined according to the disease burden strata. Treatment is allocated by randomisation. Patients may be allocated to one of three initial treatments:

A. standard surgery (ILND); B. neoadjuvant chemotherapy followed by standard surgery (ILND); or C. neoadjuvant chemoradiotherapy followed by standard surgery (ILND).

After ILND, patients are defined as being at low or high risk of recurrence based on histological interpretation of the ILND specimen. Patients at high risk of relapse are eligible for InPACT-pelvis, where they are randomised to either:

P. prophylactic PLND Q. no prophylactic PLND

This phase III trial compares the effect of decreased number of radiation (ultra-hypofractionated) treatments to the usual radiation number of treatments (hypofractionation) with standard of care chemotherapy, with cisplatin, gemcitabine or mitomycin and 5-fluorouracil for the treatment of patients with muscle invasive bladder cancer. Hypofractionated radiation therapy delivers higher doses of radiation therapy over a short period of time. Ultra-hypofractionated radiation therapy delivers radiation over an even shorter period of time than hypofractionated radiation therapy. Cisplatin is in a class of medications known as platinum-containing compounds. It works by killing, stopping or slowing the growth of tumor cells. Gemcitabine is a chemotherapy drug that blocks the cells from making DNA and may kill tumor cells. Chemotherapy drugs, such as mitomycin-C and 5-fluorouracil (5-FU), work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Giving ultra-hypofractionated radiation may be equally effective as hypofractionated therapy for patients with muscle invasive bladder cancer.