When I was at King Fahd Int'l Airport with the 354th TFW during Desert Storm, we had the 101st Airborne set up right beside our tent city. Being Air Force, we brought portable/flushable toilets and contracted garbage collection with the local community. The army had no such luxury. For months, they had burn pits a couple hundred yards outside our living area on a slight hill. Sewerage, trash, everything. I would see them outside my work area constantly burning, filling the air with black smoke. Some say you can't make that tie but boy, I would never doubt it. I have only had cardiac and arthritic conditions so I consider myself lucky (knock on wood) no cancer.
BTW, we had to fence our area to keep the Army separate. They were coming over and stealing our portable air conditioners. Each of the Air Force tents had a huge AC to keep them cool.
No doubt that the burning can be related to lung problems, thyroid issues, and blood disorders like leukemia. The causal chain is pretty well documented in medical research. However, other than exposure to ionizing radiation, the cause of gioblastoma is unknown. Some researchers believe it can be linked to a genetic disorder.
Again, for the third time, I have no problem compensating troops for any condition that could POSSIBLY arise from serving the country (or even not related to service). Spending that money actually does some good, compared to the billions upon billions of tax dollars poured into the garbage disposal.