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【medical-news】胰腺癌疫苗有望
Pancreas cancer vaccine hopeful
By Ed Susman Jan 22, 2007, 21:58 GMT
ORLANDO, FL, United States (UPI) -- Cancer researchers continue to plug away in attempts to treat one of mankind`s worst malignancies: pancreatic cancer.
In a series of studies presented at this weekend`s 4th Gastrointestinal Cancers Symposium, doctors suggested different strategies for combating pancreatic cancer, including a novel vaccine that appears to extend survival in those pancreatic-cancer patients who undergo surgery to try to check the disease.
Unfortunately, pancreatic cancer is a silent killer, and only in a few cases is the disease detected in time to permit radical surgery to remove the organ -- and even in these cases, survival is limited.
'We seem to run into a wall about 18-19 months after surgery,' Charles Staley, professor of surgery and chief of surgical oncology at Emory University in Atlanta, told United Press International.
The American Cancer Society estimates that 33,730 new cases of pancreatic cancer are diagnosed in the United States and 32,300 patients die due to the disease each year.
Staley was upbeat about the report from Dan Laheru, assistant professor at John`s Hopkins University in Baltimore, that suggested that patients given a vaccine derived from other pancreatic cancer cell lines survived an average of 26.8 months after surgery.
'Those six to seven extra months are important,' Staley told UPI.
Laheru and colleagues at Johns Hopkins recruited 60 patients to test the vaccine. The patients first underwent surgery to remove the cancer. If the patients remained cancer-free after one month following surgery, they received the first infusion of 25 million cells from each of two cell lines.
The vaccine was constructed of lethally irradiated pancreatic cancer cells, engineered to include a granulocyte macrophage colony stimulating factor (GM-CSF) gene that recruits immune-system cells to seek and destroy microscopic cancers.
The patients received additional infusion of the engineered cells at four-week intervals for three cycles, followed by a fifth infusion six months later. Overall, from surgery to final infusion of the vaccine cells, 18 months passed.
'Our initial review suggests that the vaccine could provide additional benefit over chemoradiotherapy, but prospective randomized trials are needed to confirm this observation,' Laheru said.
He said the researchers are in the process of reviewing the data before moving on to phase 3 studies with the vaccine. He suggested that those studies might commence by the end of 2007.
Two other studies suggest that giving patents with pancreatic cancer more intense radiation and chemotherapy could extend survival.
'Our findings show that surgery should be complemented by both radiation and chemotherapy for best results,' said Robert Miller, a radiation oncologist at the Mayo Clinic in Rochester, Minn.
Mayo researchers reviewed results of 254 patients who had undergone surgery at Mayo facilities in Minnesota and Arizona from 1975 to 2005. They found that the 26 patients who had surgery, then underwent chemotherapy plus radiation therapy, and then had additional chemotherapy, achieved a 61-percent two-year survival and a 40-percent five-year survival.
On the other hand, 187 patients who underwent similar surgery -- but did not receive any additional treatment -- had a 39-percent two-year survival and a 19-percent five-year survival.
In a French study about 71 percent of patients survived at least one year without recurrence. Fran莽oise Mornex, professor of radiation oncology at Centre Hospitalier Lyon-Sud, said, 'The study treatment, including induction chemotherapy plus chemoradiation, was feasible and well-tolerated.'
Mornex and colleagues enrolled 54 patients in the clinical trial. In their report they discussed outcomes on 49 patients -- 26 men and 23 women. After surgery the patients were given courses of chemotherapy, then underwent more chemotherapy along with radiation therapy.
While the treatments seem beneficial, doctors noted they have to perform additional trials for longer periods before they can accept the new therapies as viable treatments.
One of those treatments that was put to a rigorous phase 3 study proved disappointing. Researchers hoped to show that by adding bevacizumab (Avastin) to gemcitabine (Gemzar) outcomes in pancreatic cancer would be improved.
'This study did not confirm the promising data reported for gemcitabine and bevacizumab in the prior phase 2 trial, likely because that small study had proportionally more patients with good prognostic factors,' Hedy Lee Kindler, associate professor of medicine and medical director of gastrointestinal oncology at the University of Chicago Hospitals, told UPI.
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作者:admin@医学,生命科学 2011-03-01 17:11
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