May 18, 1999
This tip sheet highlights research news from Johns Hopkins that are either the subject of presentations or ongoing issues that provide context for presentations at the annual meeting of the American Society of Clinical Oncology.
Hopkins Researchers Show Change in Medicare Payment Policies Affects Cervical Cancer Rates: Hopkins researchers have found a decline in invasive cervical cancer rates among women aged 65 and older resulting from Medicare's 1990 decision to cover payment for screening pap smears. This level of decrease in cervical cancer incidence was not found in the years prior to the Medicare policy change. Data were collected from 1988-1995 from the California Cancer Registry to compare annual invasive and localized cervical cancer incidence before and after the change in Medicare payment policy. The researchers compiled the incidence of cervical cancer rates among White, Black, Hispanic, and Asian women aged 25 and older. Although the study shows a rapid decrease in cervical cancer incidence among women over 65 years of age for all races combined, the Hopkins team found, however, that incidence rates among Medicare eligible Blacks and Asians alone did not decrease as quickly when compared to other races.
Agent that Blocks Blood Vessel Constrictor Being Tested as Therapy for Treatment-Resistant Prostate Cancers: Investigators at Johns Hopkins have begun clinical trials in prostate cancer patients involving a blood vessel contrictor known as endothelin-1 (ET-1). ET-1 works by binding to the endothelin A receptor (ETA). The drug, ABT-627, blocks the ETA receptor, thereby blocking the effects of ET-1. Using the ETA receptor antagonist may inhibit the progression of many tumor types and may alleviate the pain associated with tumor metastases. Early human clinical studies demonstrated reduction in both PSA levels and pain. The researchers believe use of this agent may provide a new and novel pathway for the treatment of many cancers. Phase II trials for prostate cancer are currently underway.
Gene and Vaccine Therapy for Prostate Cancer: Hopkins researchers continue to develop strategies to eliminate treatment-resistant cancer cells in prostate cancer patients. Hopkins was the site of the first Phase I/II gene therapy trial using cancer cells genetically engineered with the immune cell boosting GM-CSF gene to effectively target and eliminate prostate cancer. The GM-CSF gene is used to activate dendritic cells - the most potent type of antigen-presenting cells in the human body. Among the advancements is the evolution of this vaccine from individual tumor specific to allogeneic or non-tumor specific cell lines.
Effect of Chemohormonal Therapy in Premenopausal Women with Breast Cancer: Researchers have found that combined treatment with chemotherapy, hormone therapy and tamoxifen increases five-year, disease-free survival in premenopausal women with node-positive breast cancer. In a national trial of over 1,500 women, the benefits of chemotherapy alone, chemotherapy plus hormonal therapy, or chemotherapy plus hormonal therapy and tamoxifen were assessed. The hormone therapy consists of administration of a compound that works by temporarily shutting down the ovaries. Tamoxifen, also a form of hormone therapy, is approved by the FDA for the treatment of breast cancer and reduction of the risk of breast cancer diagnosis in high-risk women.
Combined Modality Treatment Improves Survival for Esophageal Cancer Patients: Hopkins researchers have found that combined treatment with chemotherapy, radiation and surgery improves the survival of esophageal cancer patients. In a five-year study, researchers followed 92 patients receiving chemotherapy and radiation therapy prior to surgery for esophageal cancer. With an average follow-up of 40 months, the three-year survival rate of all patients in this study is 46% compared to the current average three-year survival rate of approximately 19%. Some patients, even those with more advanced disease, achieved tumor reduction which is associated with long-term survival. While esophageal cancer makes up a small percentage of all cancers diagnosed annually, it is most frequently diagnosed after it has reached an advanced, more treatment-resistant stage.
Watching and Waiting is the Best Treatment for Some Childhood Brain Cancers: Hopkins researchers have found that the best initial treatment for children with tectal gliomas, which account for 10% of all brainstem cancers, is no treatment at all. Investigators found sustained survival rates even when MRI examination showed increases in tumor size. Hopkins researchers say continued observation despite MRI evidence of tumor progression could avoid neural and endocrine damage to the developing brain that may be induced by radiation and chemotherapy. They recommend treatment only when patients show new abnormal neurological exam findings rather than MRI progression.
Human Papillomavirus (HPV) Linked to Head and Neck Cancer: Hopkins researchers have found that human papillomavirus (HPV), the virus responsible for causing cervical cancer, is found in 25% of head and neck cancers. Using several molecular analysis techniques including viral gene sequencing and polymerase chain reaction, or PCR, to amplify and detect the presence of HPV in tumor specimens, the research team found HPV gene sequences in 61 out of 254 tumors. Evidence of HPV was most commonly found in the DNA of tumors that arose from the tonsils and also expressed a normal P53 gene. The Hopkins research shows that patients with HPV in their tumors reduce the risk of dying from their head and neck cancer by 60% when compared to patients without HPV in their tumors.
Hopkins Researchers Find that Patients at High Risk for Colon Cancer Do Not Adhere to Recommended Screenings: Patients receiving negative colon cancer gene test results appear less likely to follow screening recommendations according to a Johns Hopkins study. Hopkins researchers analyzed records from 65 patients seen at the Johns Hopkins Cancer Risk Assessment Clinic to find that the percentage of patients having recommended follow-up colon exams was lowest for those receiving negative gene tests for colon cancer. Accordingly, patients receiving positive gene tests generally adhered to recommended screening. Researchers speculate that patients with negative results may receive false reassurance about their cancer risk and fail to follow recommended screening. This provides evidence that more emphasis should be placed on strict adherence to screening recommendations regardless of gene test results.