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In the 1990s, the Food and Drug Administration (FDA) approved a treatment for bladder cancer called Bacillus Calmette-Guerin therapy, or BCG, which stimulates the immune system and helps keep patients’ cancer from coming back.
Until recently, BCG was still the newest FDA-approved treatment for bladder cancer. But about one-third of patients won’t respond to BCG. This can limit patients’ treatment options to bladder removal surgery, but many people with bladder cancer are older and not able to handle such a major procedure. And many patients don’t want to undergo the surgery even if they’re healthy enough for it.
In recent years, however, we’ve begun to find alternatives to BCG. Beginning in 2015, several new therapies have been approved that have revolutionized the way we treat bladder cancer. And like BCG back in the ’90s, these treatments harness the power of the immune system to battle this disease.
As of November 2017, these immunotherapy treatments currently are approved for patients whose disease is further along and hasn’t responded well to other treatments, such as traditional chemotherapy and surgery. But we’re currently investigating new ways to use immunotherapy, as well as how to use it sooner in the disease process.
How does immunotherapy work to treat bladder cancer?
One of the ways cancer can survive and grow within the body is by deactivating the immune system. The bladder’s cells, like all cells in the body, have a system to prevent them from growing out of control. Like inserting a key into a lock, immune cells can bind to bladder cells that are growing too much and kill them without harming healthy cells.
But in cases of bladder cancer, the cancer cells can “trick” the immune system by hijacking this process. Bladder cancer cells use certain proteins to turn off immune system cells before they can destroy the cancer cells. This allows the cancer cells to grow out of control, forming tumors that can spread from the lining and connective tissue of the bladder into the muscle.
The latest immunotherapy treatments work by preventing this interaction. By stopping the cancer cells from turning off the immune system cells, we can increase the immune system’s ability to find and destroy cancer cells.
Personalized treatments for bladder cancer
There are multiple clinical trials going on with the hope of expanding our use of immunotherapy. Some examples of these potentially expanded uses include:
- Combining immunotherapy with other treatments to kill cancer cells even more effectively
- Treating someone with a new diagnosis of metastatic bladder cancer, or cancer that is spreading beyond the bladder wall
- Treating someone with immunotherapy before surgery
- Treating someone with immunotherapy before their bladder cancer spreads into the bladder muscle
Here at MedStar Washington Hospital Center, we’re participating in a clinical trial for patients whose bladder cancer hasn’t invaded the bladder muscle. In particular, this trial is examining patients who haven’t responded to BCG, the standard of care for bladder cancer approved back in 1990. Patients who don’t respond to BCG may be candidates for this new treatment, called Vicinium. Though this isn’t a form of immunotherapy, it’s an exciting approach to targeting bladder cancer cells. When we introduce Vicinium into a patient’s system, it makes its way to bladder cancer cells, avoiding healthy cells along the way. Next, it blocks the cancer cells from creating the proteins they need to survive, which causes the cancer cells to die off.
The new treatments we have available for bladder cancer and those currently being tested all are part of a growing wave of personalized medicine in cancer care. Until very recently, although we customized each patient’s particular treatment strategy for that patient, we’ve had the same sorts of treatments available to choose from.
Many researchers are studying information we can get from the patient during the first bladder cancer biopsy to see if we can recommend particular treatments based on whether the patient will benefit from them. For example, if we could identify whether a patient is likely to benefit from the chemotherapy treatment, we could know whether we should recommend that or go straight to surgery. Like immunotherapy, this is another way we can tailor care to the individual patient.
The field of bladder cancer treatment has made great strides forward in the last few years. In the next five to 10 years, it could look radically different than it does today. I’m excited for the chance to help more of my patients, and I’m eager to see what happens next.