Doctors
and patients must work together to change the status quo in bladder
cancer treatment.
By Beverly
A. Caley
“I am convinced I will die in front of a truck
or by falling off a mountain or of a heart attack. I do not believe
this is going to kill me.”
Thomas Touzel’s confidence
comes despite having already been through four surgeries to remove
dozens of tumors from his bladder.
Diagnosed in 2003 at the age of 64, right now he feels great. Most
cases of bladder cancer are chronic but treatable, while others
are lethal within a year or two. Touzel has the more treatable type. “They
do a scope and do some chop-chop when necessary,” is how he
describes his ongoing treatment. “It’s just a question
of maintenance.”
Of the more than 61,000 new cases of bladder
cancer estimated for the United States in 2006, about 90 percent
will be in people over age 55 and nearly 45,000 will be men—white
men for the most part. Although progress is being made in understanding
the origins and development of the disease, experts say insufficient
funding, poor accrual to clinical trials and lack of public awareness
of bladder cancer have left promising new treatments under-researched.
Obstacles to New Treatments
Despite its ranking as the sixth most
common cancer in the United States, according to the American Cancer
Society, and a recurrence rate of at least 50 percent (see sidebar), the biggest challenge in terms of developing new treatments
is enrolling patients in clinical trials, says Walter Stadler, MD,
director of the genitourinary program at the University of Chicago
Hospitals. Smoking is the biggest risk factor for bladder cancer,
so since the disease mainly afflicts men who smoke and have concurrent
diseases, “smoking
history and things like hypertension and prior surgeries mean
that these patients often have problems with kidney function,
and that limits our ability to give certain chemotherapy drugs,” Dr.
Stadler explains. Delayed enrollment also impacts eligibility. “By
the time oncologists run out of options, the patients are too
sick to enter a clinical trial,” says Dr. Stadler.
Funding
for bladder cancer research is also an issue. Michael O’Donnell,
MD, director of urologic oncology at the University of Iowa Hospitals,
says researchers have made some promising discoveries in laboratory
experiments for a possible vaccine that could target specific attributes
of bladder cancer tumors. “Unfortunately, there is not much
commercial interest in this kind of development,” Dr. O’Donnell
says. While a lack of interest may in part stem from the perception
of bladder cancer as an “old white man’s disease,” those
affected are starting to take action.
A 2002 national task force
identified the need for a nationwide advocacy group for bladder
cancer to help establish research priorities at the national level
and advocate for scientific studies and clinical trials. Three years
later, the wife of a bladder cancer patient founded the Bladder
Cancer Advocacy Network.
Diane Zipursky Quale, whose husband John
was diagnosed with bladder cancer in 2000, says cancers for which
a lot of new research is being done can be traced in part to the
patient advocacy groups. “So
much is being done in breast cancer, prostate cancer and colon cancer,
in large part because the advocacy groups stepped forward and said, ‘We
need something better.’ ” Zipursky Quale hopes BCAN
will increase awareness and engage the bladder cancer community
so that more research funds will be devoted to exploring better
treatments.
“Groups like BCAN can make a big impact,” says Dr.
Stadler. “Getting
patients, community physicians and everybody on the same page is
a very important step.” He also urges patients to get more
involved in their care. “It
would go a long way in galvanizing some of the research efforts
out there if the patients would ask, ‘Why are we doing this?
How could we make this better?’ ”
Touzel did just that.
After researching emerging treatments for bladder cancer, he moved
more than 1,100 miles from Florida to Texas to be near M.D. Anderson
Cancer Center in Houston. “I’m
not a rocket scientist, but within days I knew where I wanted to
be and what doctor I wanted to treat me,” Touzel says.
Mistaken Identity
Pat Screeden of St. Charles, Illinois, was 54
when she first noticed a small amount of blood in her urine, known
as hematuria, in December 2003. She received a prescription for
antibiotics for what was thought to be an infection. About six weeks
later, the hematuria showed up again and she was given another round
of antibiotics. When the hematuria returned yet again a month later,
Screeden consulted a urologist. Several tumors were revealed during
a procedure known as a cystoscopy in which a thin tube with a lens
and light (a cystoscope) is placed in the bladder through the urethra.
People
should not ignore blood in their urine, says Dr. O’Donnell. “It’s
not normal and it isn’t always a simple urinary tract infection.
If they have no symptoms of infection, they should consider that
bladder cancer is a possibility and ask their physicians.”
When
bladder cancer is suspected, cystoscopy is the most common diagnostic
test. In addition to enabling the physician to see inside the bladder
to determine if tumors are present, cystoscopy allows tissue samples
to be taken for a biopsy. Another common test is urine cytology,
which examines urine under a microscope for abnormal cells.
A new
diagnostic tool for the detection of bladder cancer is known as
fluorescence cystoscopy, which uses a photosensitizing agent known
as hexaminolevulinate (HAL) that is administered within the bladder.
Studies have shown that HAL fluorescence cystoscopy is able to identify
very early-stage bladder tumors that are not visible with conventional
white-light cystoscopy.
A more modern type of test uses chemicals
or antibodies to identify specific substances released by cancer
cells that may be present in urine. About 20 such tests are available
for bladder cancer diagnosis, but the Food and Drug Administration
has approved only a handful, including ImmunoCyt™, NMP22 BladderChek® and
UroVysion™,
each of which looks for a different substance. These tests are not
accurate enough to replace cystoscopy, but a major effort is under
way to develop a urine-based test that could, says Dr. O’Donnell.
The
biopsy taken during cystoscopy reveals the specifics of the bladder
cancer, including type, stage and importantly, the grade. Grade
indicates the aggressiveness of the cancer with designations of
low-grade or high-grade cancer, each of which behaves very differently
in terms of tumor biology and prognosis.
Low-grade noninvasive bladder
cancer accounts for about 80 percent of cases and is often multifocal,
meaning several tumors form simultaneously at different locations
within the bladder. Two theories attempt to explain the multifocal
nature of these tumors. The first identifies bladder cancer as a
so-called field disease, a concept first introduced in 1953 that
suggests tumors develop independently because the entire field of
tissue presumably has more prolonged exposure to environmental carcinogens
in the urine. The second, known as the monoclonality theory, is
supported by genetic studies that point to seeding of cancer cells
in the urinary tract that originated from a single primary tumor.
Patients with low-grade disease often have recurrences, with only
about 15 percent progressing to invasive cancer. High-grade, muscle-invasive
bladder tumors are much more severe for the 20 percent of patients
diagnosed. More than 50 percent of these patients experience metastasis
despite aggressive treatment.
Diverting the Flow
Once doctors make a detailed diagnosis, surgery,
chemotherapy, immunotherapy and radiation can be used in various
combinations, depending on the stage and aggressiveness of the cancer.
For early-stage bladder cancer, surgeons often remove tumors with
a decades-old procedure called transurethral resection of the bladder,
or TURB. The surgeon inserts a type of cystoscope called a resectoscope
into the bladder through the urethra. The device contains a small
wire loop at the end that is used to remove the tumors. Fulguration
often accompanies TURB, in which cancer cells are burned away with
an electrical current. In addition to its therapeutic use, TURB
also provides doctors with tissue for determining the type, grade
and stage of the tumor.
If bladder cancer has invaded the muscle
beyond the inner bladder lining, a radical cystectomy is done to
remove the bladder and nearby organs and lymph nodes. Researchers
are looking into whether partial cystectomy, during which surgeons
remove only part of the bladder, may be an option for some patients
in order to retain bladder function. Experts, however, disagree
about the usefulness of this treatment since most bladder cancers
involve several sites in the bladder and the risk of recurrence
is higher when only part of the bladder is removed.
Patients who have their bladders removed must undergo
reconstructive surgery to create a new method for the body to store
and drain urine. Screeden had tumors removed in a TURB procedure,
but after tests found her cancer was in multiple locations, her
bladder was removed. Doctors constructed a new bladder for her through
a urinary conduit, a simple operation where a segment of the small
intestine directs urine through a stoma into an external collecting
bag.
An option that eliminates the need for an external bag is a catheterizable
stoma, an internal pouch that is drained using a catheter. The most
complex reconstruction procedure involves the surgeon essentially
creating a new bladder, or neobladder, where the intestine is made
into a storage area and attached to the urethra.
Adding Drug Therapy
TURB is usually followed by treatment administered
within the bladder to rid the organ of any tumor cells that broke
off during TURB. Called intravesical therapy, this type of immunotherapy
uses the body’s own immune system to fight cancer. The agent
most often used for intravesical treatment is bacillus Calmette-Guérin
(BCG), a form of bacteria that is sometimes used as a tuberculosis
vaccine. The treatment is typically given once a week for six
weeks, and although much of the drug is washed out during urination,
a good amount remains in the bladder.
Researchers believe BCG works
by alerting the cells lining the bladder of a brewing infection,
which results in infection-fighting white blood cells rushing to
the bladder. But unlike the normal chain of events that occurs with
urinary tract infections, Dr. O’Donnell
says BCG causes the white blood cells to release a tumor-killing
compound called TRAIL (tumor necrosis factor-related apoptosis-inducing
ligand) that is effective in destroying cancer cells but spares
normal cells. Chemotherapy agents, such as Valstar® (valrubicin),
Mutamycin® (mitomycin)‚ Adriamycin® (doxorubicin)
or Thioplex® (thiotepa), may also be used for intravesical therapy.
A
standard of care for cancer that has spread outside the bladder
involves a combination of Gemzar® (gemcitabine) and cisplatin,
therapy that John Quale received after multiple tumors were found
in his bladder that had spread to his liver and nearby lymph nodes.
Before
his wife created BCAN in 2005, Quale, now 60, experienced numerous
recurrences that led to additional surgeries and chemotherapy treatments.
He’s currently recovering from having his bladder
removed this past September.
Another cisplatin-based chemotherapy
known as M-VAC, a combination of methotrexate, Velban® (vinblastine),
Adriamycin and cisplatin, has “essentially fallen out of favor” because
of its side effects, says Maha Hussain, MD, professor of internal
medicine at the University of Michigan. She says the combination
of cisplatin and Gemzar is now most commonly used in clinical practice.
Currently,
data fail to show a benefit for treatment given after surgery, but
for patients who receive chemotherapy before surgery, studies have
shown statistically significant improvements in both overall survival
and disease-free survival. Dr. Hussain says newly diagnosed early-stage
bladder cancer patients should discuss this option with their oncologists
before surgery. “It doesn’t
mean they have to take the chemotherapy. It means they know their
options,” she says.
Cancer Targets
Most bladder cancer clinical trials are exploring
different combination regimens of chemotherapy, targeted agents
and immunotherapy. Recently, investigators combined Herceptin® (trastuzumab)
with standard chemotherapy after tests found that about half of
patients had excess HER2 on the surface of their bladder cancer
cells. Herceptin blocks the effects of the growth factor protein
HER2, which transmits growth signals to cancer cells. Early results
show that 70 percent of patients are responding to the drug. Further
testing is expected that will compare chemotherapy with and without
Herceptin.
Another new combination is BCG with interferon, which
stimulates the growth and action of immune system cells that fight
disease and infection. The combination was effective in patients
regardless of whether they received previous treatment with BCG.
Dr. O’Donnell,
the trial’s lead investigator, says the combination worked
particularly well for patients with high-grade disease, though older
patients did not respond well to the combination.
Javlor® (vinflunine),
the newest drug in a class of agents known as vinca alkaloids, is
in phase III testing for bladder cancer. Researchers are also testing
kidney cancer drugs Sutent® (sunitinib)
and Nexavar® (sorafenib) and colorectal and lung cancer drug
Avastin® (bevacizumab) in hopes of duplicating the drugs’ response
rates for bladder cancer by targeting the pathway that promotes
blood vessel formation and proliferation of tumor cells. Other novel
bladder cancer treatments in development include E7389, a synthetic
version of halichondrin B, which is a naturally occurring substance
found in South Pacific sea sponges, and Alimta® (pemetrexed),
a therapy approved for lung cancer.
Doctors and patients agree that
current treatments for bladder cancer are not good enough, and despite
studies testing targeted agents and other combination regimens,
more must be done. For patients with locally advanced disease, better
chemotherapies before surgery could lengthen survival, and better
treatments after surgery could reduce high recurrence rates. Experts
say effort also needs to be focused on improving therapy for patients
with metastatic disease. Bladder cancer patients and their families
can help change the status quo by demanding new treatments. Dr.
Hussain says improvements in survival can only come from better
treatments. “Doctors and
patients must partner in discovering them.”
|