Researchers at NCI's Center for Cancer Research (CCR) testing an experimental vaccine against prostate cancer have found it to be safe when given to patients undergoing local radiation therapy, according to a pilot study published in the May Clinical Cancer Research.
The study was the first clinical trial to combine radiation and a cancer vaccine to treat prostate cancer. Larger clinical trials can now go forward to evaluate the therapy as a treatment for localized forms of the disease.
"We have shown that this combination therapy is safe and well tolerated," says lead author Dr. James L. Gulley of CCR's Laboratory of Tumor Immunology and Biology. "This is the first step toward finding alternative treatments for patients with localized prostate cancer." About a third of patients who receive radiation or surgery for localized prostate cancer relapse within a decade.
Cancer vaccines are intended either to treat existing cancers or to prevent the development of new ones. The experimental vaccine in this study was designed to strengthen the body's natural defenses against prostate cancer. "The idea is that you can stimulate the body's immune system to recognize and attack tumor cells through the use of a vaccine," explains Dr. Gulley.
Thirteen of 17 patients who received the experimental therapy (vaccine plus local radiation of tumor) had at least a threefold increase in the immune cells that attack a protein made by the tumor cells, compared with no detectable increases in those immune cells in 8 patients who received radiation alone. A strong immune response is an indication that the body is fighting the cancer.
Researchers have closed a clinical trial testing gefitinib (Iressa) for patients with non-small-cell lung cancer (NSCLC) as a maintenance therapy following chemotherapy and radiation. Review of interim data indicated that gefitinib would not improve survival in the patient group studied.
The NCI-sponsored study was designed to evaluate whether gefitinib could control NSCLC and extend survival when given to patients whose disease has not spread beyond nearby tissues or lymph nodes and is responding or stable after primary therapy. After reviewing the available study data, the independent committee overseeing the trial recommended closure.
"Based on the analysis, the use of gefitinib following chemotherapy and radiation should not be prescribed for this group of patients," said Dr. Scott Saxman of the Cancer Therapy Evaluation Program, who oversees lung cancer clinical trials for NCI.
The trial was conducted by the Southwest Oncology Group (SWOG). A total of 672 patients were to be randomized to 1 of 2 treatment groups following chemotherapy and radiation: one group would receive gefitinib daily and the other would receive a placebo daily. By early March 2005, 611 patients had been entered and 276 had been randomized.
"The interim analysis indicates that even with accrual of more patients or with longer follow-up, the gefitinib arm would not improve survival," explained Dr. Laurence Baker, SWOG chairman and professor of internal medicine and pharmacology at the University of Michigan.
On April 22, the National Cancer Institute of Canada (NCIC) closed its clinical trial of gefitinib for NSCLC after a review of the SWOG results by its Data and Safety Monitoring Committee, according to Dr. Joe Pater, who directs the NCIC Clinical Trials Group.
Removing the aortic and pelvic lymph nodes during surgery for advanced ovarian cancer improves progression-free survival but not overall survival, according to a study in the April 20 Journal of the National Cancer Institute.
To determine whether systematic aortic and pelvic lymphadenectomy improves progression-free and overall survival, researchers at the Università La Sapienza in Rome conducted a clinical trial in which 427 patients with advanced ovarian cancer were randomly assigned to undergo either primary cytoreductive surgery followed by lymphadenectomy or cytoreductive surgery alone, which only removes the tumor and lymph nodes in the abdominal cavity. The patients were followed for an average of 68.4 months.
Researchers found that, on average, women receiving lymphadenectomy surgery went 7 months longer without recurrence of their cancer. However, the study results also confirmed the higher incidence of complications associated with lymphadenectomy surgery, which requires longer operating times and the increased likelihood for blood transfusions. They noted that overall survival was not improved for lymphadenectomy patients.
In an accompanying editorial, Dr. Setsuko Chambers of the Arizona Cancer Center commented, "This pivotal trial should be considered definitive, and the findings used to dictate clinical management…As disappointing as the result may be to some gynecologic oncologists, the body of evidence does not favor including systematic lymphadenectomy as part of front-line maximal surgical debulking in the management of advanced ovarian cancer."
Human papillomavirus (HPV) infection was found in more than half of patients with colorectal cancer, an NCI study reported in the April 15 Clinical Cancer Research.
Researchers in the HIV and AIDS Malignancy Branch of NCI's CCR found that 28 of 55 (51 percent) of the colorectal cancer patients studied were positive for HPV based on examination of samples from tumors and adjacent tissues. Colorectal tissue from 10 control individuals, who didn't have colorectal cancer, were all negative, they noted.
The findings confirm previous controversial studies linking HPV with colorectal cancer, but the NCI researchers were careful to avoid the cross-contamination of tissue samples in the detection that may have affected earlier research.
Dr. Zhi-Ming Zheng, principal investigator in the study, explained the precautions taken: "All samples of normal tissues taken from healthy subjects along with counterpart tumor and tumor-adjacent tissues from colon cancer patients had to be examined in a blinded manner, using three separate nested polymerase chain reactions, each targeting a different region (L1, E6, and E2) of the virus genome." A positive sample had to be confirmed in multiple repeats to be considered a real positive for HPV, he added.
Dr. Zheng addressed the implications of the study: "Establishing a firm relationship between HPV infection and the development of colorectal cancer will require further research. However, it is quite likely that diseases caused by HPV infection will soon become preventable by vaccination. If this study is confirmed and a substantial proportion of colorectal cancers are ultimately found to be etiologically associated with HPV infections, this would help us to further understand the oncogenesis of colorectal cancer and might change our views on its prevention and treatment."