Press Releases

EMBARGO: Monday, October 4, 2004, 2:30 PM ET

New research shows that prostate cancer patients who have a negative biopsy following high-dose radiation therapy are more likely to have a cancer-free long-term prognosis than those who have a positive biopsy. According to the findings, patients with non-positive biopsies were also more likely to be free of metastasis ten years after treatment.

Patients in the study were treated with three-dimensional conformal radiation therapy (3D-CRT), a form of external-beam radiation that shapes the radiation beam to the contours of the tumor, allowing for high doses of radiation to be precisely delivered to the cancer while sparing surrounding healthy tissues. The findings indicate that:74 percent of 306 prostate cancer patients treated with 3D-CRT had a non-positive biopsy; of those patients, about 60 percent remained cancer-free 10 years after treatment. Patients treated with the highest doses of 3D-CRT had a better prognosis and experienced long-term prostate specific antigen (PSA) control rates; 26 percent of the 306 patients had a positive biopsy; of these patients only seven percent had a ten-year relapse-free survival.

The study was led by Michael Zelefsky, MD, Chief of the Brachytherapy Service in the Department of Radiation Oncology at MSKCC.

EMBARGO: Wednesday, October 6, 2004, 10:30 AM ET

Information gleaned from a technique called magnetic resonance spectroscopic imaging (MRSI) can help doctors determine how aggressive a particular cancer is, allowing them to target those abnormal areas with intensified doses of radiation. While MRSI can potentially be used to improve the accuracy of the radiation beam when treating brain cancers called gliomas, it lacks the anatomic information necessary for doctors to know precisely where the tumor is.

In this study, MSKCC investigators developed a way to fuse MRSI images with computed tomography (CT) images (indicating exactly where the tumor is) to help doctors plan radiation therapy for glioma patients. The treatment method used in the study was Intensity Modulated Radiation Therapy (IMRT), an advanced form of 3D-CRT in which the beam simultaneously delivers different dose levels to the tumor based on the MRSI information - and no part gets too large a dose - reducing the risk of side effects.

The researchers successfully used this image fusion technique in IMRT planning for 12 glioma patients. They found that the MRSI information correlated with the glioma grade from pathology findings, and that the average agreement between the MRSI and CT image overlays was within .5 millimeters.

The research was led by Jenghwa Chang, PhD, Assistant Attending Physicist in the Department of Medical Physics at MSKCC.

Eight-Year Study Finds High-Dose Radiation is Safe and Effective for Prostate Cancer Patients

EMBARGO: Monday, October 4, 2004, 2:30 PM ET

MSKCC investigators have concluded that IMRT is effective in and well tolerated by patients with clinically localized prostate cancer, based on a study offering the longest follow-up data available among such patients treated with IMRT. Data from this long-term study confirm previous observations that high-dose radiation therapy is required to eradicate early stage prostate cancer and that high-dose IMRT is safe, with low rates of serious long-term complications such as rectal bleeding.

In this study, 170 patients were treated with high-dose levels of IMRT to 81 Gy and were followed for up to 8.25 years. Fifty-four percent of the patients also received a three-month course of hormone therapy prior to IMRT. PSA blood test results were used to determine whether a patient experienced a biochemical relapse (recurrence of disease). The findings indicate that eight years after treatment: Only three percent of all patients experienced rectal bleeding, which had been a common side effect of high-dose radiation. When compared to patients treated with similar doses of 3D-CRT, high-dose IMRT was associated with a much lower rate of rectal bleeding;No patients experienced any serious long-term urinary side effects.

In addition, 91 percent of patients with favorable risk (least likely to relapse) remained cancer-free (did not experience a biochemical relapse); 72 percent of patients with intermediate risk remained cancer-free; and 62 percent of patients with unfavorable risk (most likely to relapse) remained cancer-free eight years after treatment.

The study was presented at ASTRO by Heather Chan, Research Study Assistant in the Department of Radiation Oncology at MSKCC.

Memorial Sloan-Kettering Cancer Center is the world's oldest and largest institution devoted to prevention, patient care, research and education in cancer. Our scientists and clinicians generate innovative approaches to better understand, diagnose and treat cancer. Our specialists are leaders in biomedical research and in translating the latest research to advance the standard of cancer care worldwide.