Apr. 25, 2001 COLUMBUS, Ohio - Researchers have found a relatively simple way to dramatically improve the cancer-killing capacity of a drug often used to treat superficial bladder cancer.
The changes nearly doubled the number of people who were cancer-free after five years, compared to those receiving the standard therapy, and lengthened the time before tumors recurred in these patients.
The finding is the result of a five-year, international study published in the April 18 issue of the Journal of the National Cancer Institute.
The study looked at ways to improve the use of mitomycin C (MMC) following surgical removal of the tumor. In both the standard and the experimental therapy, MMC is placed in the bladder where it is held by the patient for about two hours.
The new therapy, however, took special measures to maintain a high drug concentration in the bladder.
"We compared the usual way of giving the drug to a new approach, said Jessie L-S Au, distinguished university professor and Dorothy M. Davis Chair in Cancer Research at the College of Pharmacy at Ohio State University.
Patients receiving the experimental treatment went an average of 29.1 months before their cancer recurred, while those receiving the standard treatment had recurrence in 11.3 months.
There was also a statistically significant difference in the number of patients who were recurrence-free after five years: 42.6 percent in the modified treatment versus 23.5 receiving standard treatment.
"We have found a way to make this treatment more effective in a highly significant way," said Au, a researcher with Ohio State's Comprehensive Cancer Center. "We nearly doubled the percentage of patients who were disease-free after five years."
The study, done by Au and a team of researchers, involved 230 patients with confirmed superficial bladder cancer who were at high risk of recurrence. Of these, 111 patients received standard treatment and 119 received the experimental therapy.
For the standardized therapy, urine was drained from the bladder using a catheter. Then, a 20-mg dose of MMC was placed in the bladder, where it was held for two hours. No special steps were taken to reduce the remaining volume or to reduce urine acidity.
The experimental therapy used a 40-mg dose of MMC and several steps were taken to maintain a high drug concentration in the bladder by reducing urine volume.
For example, patients were instructed to abstain from drinking water prior to and during treatment to reduce urine production. Steps were also taken to drain as much urine from bladder as possible just prior to treatment.
Lastly, patients were given doses of sodium bicarbonate to reduce urine acidity, a factor known to inactivate MMC.
Next, Au will also try to improve the efficacy of MMC further by using an additional drug to make the tumor more sensitive to the drug. Au's study was sponsored by the National Cancer Institute and was done in conjunction with The Ohio State University Comprehensive Cancer Center.
Sidebar -- STUDY OF ANTI-CANCER DRUG HAS IMPORTANT IMPLICATIONS FOR AFRICAN-AMERICANS
The Ohio State study on MMC had an unexpected finding that has important implications for African Americans with superficial bladder cancer, and possibly other cancers.
The five-year, multi-institutional study, led by Jessie L-S Au, distinguished university professor and Dorothy M. Davis Chair in Cancer Research at the College of Pharmacy at Ohio State University, demonstrated a way to significantly improve the effectiveness of the drug.
Of the 230 people involved in the research, six were African Americans. Three of these patients were randomly selected to receive the standard therapy and three the modified therapy.
Regardless of treatment, however, all six people experienced a recurrence of their disease in less than one year. The difference between the African-American and the Caucasian data was highly statistically significant, said Au, but because the number of African-American patients was so low, no firm conclusions can be drawn from the outcome.
Based on this outcome, however, "mitomycin C doesn't seem like a good drug for African Americans, and an alternative drug should be tried," said Au. "I can't say which drug, though, because no one looks at race as a risk factor in clinical trials."
Au's finding indicates that should change. "This data is strong evidence that we should study race as a risk factor," she said. "Perhaps the difference is genetic. African Americans may lack the two enzymes in the body that make this drug work." Au plans to study archived tissues from African-American patients for presence of the enzymes.
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