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10.04.2011

Sylvester Radiation Oncologists Reveal New Discoveries at National Gathering

Led by renowned physician-scientist Alan Pollack, M.D., Ph.D., professor and chair of radiation oncology at Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine, several Sylvester radiation oncologists are presenting discoveries at the annual meeting of the American Society for Radiation Oncology this week in Miami Beach.

The annual gathering is a showcase of recent discoveries and clinical studies aimed at improving radiation therapy for patients. Among the presentations is a study led by Pollack which found that a shorter and more convenient five-week course of radiation appears to be just as effective as the traditional seven and one-half week schedule in men with prostate cancer.

A newer, targeted technology known as intensity-modulated radiotherapy (IMRT) was used to deliver the radiation. With IMRT, multiple radiation beams from many directions are focused on the prostate. Pollack says longer follow-up is needed since doctors discovered a slightly higher risk of urinary incontinence after five years. He says the shorter course of treatments, known as hypofractionation, is showing promise in the treatment of breast and several other types of cancer.

Locating residual prostate cancer following surgery has been the focus of work by Matthew C. Abramowitz, M.D., assistant professor of radiation oncology. Delivering high doses of radiation to the entire prostate bed is limited because of the nearby bladder and rectum. Using dynamic contrast enhanced MRI (DCEMRI) on 33 patients, Abramowitz was able to detect abnormalities in specific areas, suggesting residual or recurrent tumor. His findings from the two and a half year study suggest that combining MRI with DCE detects residual disease in a far more precise manner. Locating those specific areas will allow physicians to deliver a higher dose of radiation to more accurately defined diseased areas.

Elizabeth Bossart, M.D., assistant professor of radiation oncology, is also presenting work that helps pinpoint methods of delivering higher doses of radiation to the prostate while sparing the bladder, rectum and bowel. Using DCEMRI in a phase III study, she was able to locate areas where persistent disease may linger. With those areas identified, Bossart then delivered escalating doses of radiation while sparing nearby critical healthy tissue.

The two-year results of a phase II multi-institutional trial on the feasibility of delivering pelvic IMRT in cervical cancer patients is being presented by Lorraine Portelance, M.D., associate professor of radiation oncology. Portelance was co-principal investigator of the National Cancer Institute-funded study which treated stage I and stage II cervical cancer patients with intensity-modulated radiotherapy and weekly cisplatin. The study set guidelines for delivering pelvic IMRT, reducing treatment toxicity in women receiving post-operative chemoradiotherapy, without sacrificing efficacy.

Aaron Wolfson, M.D., professor of radiation oncology, is presenting preliminary findings of a national study looking at new advances for treating high to intermediate risk early-stage endometrial cancer. The Phase III trial is comparing pelvic external beam irradiation versus vaginal brachytherapy (VBT) and chemotherapy for these endometrial cancer patients. Wolfson’s early results indicate that adjuvant VBT and chemotherapy for patients with stage I high-intermediate risk factors or stage II disease holds promising results.

Cristiane Takita, M.D., assistant professor of radiation oncology and co-leader of the Breast Cancer Site Disease Group at Sylvester, has focused her work on early stage breast cancer patients who are triple negative, but not HER2 positive. This group has traditionally experienced a higher risk for recurrent disease following lumpectomy and radiation. Takita examined the effectiveness of newer systemic chemotherapy and Herceptin in the risk for disease recurrence in this group of patients. Triple negative breast cancer, but not HER2 positive subtype, was found to be a significant predictor for disease coming back.

Breast cancer in African American women and rare brain tumors in children are the focus of presentations by resident Joseph Panoff, M.D. Panoff and his team reviewed the cases of nearly 600 stage II-III breast cancer patients over a ten year period to better determine the importance of race in molecular subtype. His findings indicate that African American patients treated with trimodality therapy (surgery, chemotherapy and radiotherapy) had a higher proportion of an aggressive form of breast cancer and worse survival rates.

Panoff also presented research on craniopharygioma, a rare brain tumor that occurs in children. These types of tumors often change size during radiation therapy from week to week. Panoff is presenting results of a new MRI technique which allows rapid imaging in the treatment position, without having to administer anesthesia to these young patients.

Chief resident of radiation oncology, Georges A. Hobeika, M.D., is introducing research on the effect of internal target volume (ITV) based treatment planning and delivery for moving lung tumors compared with real time target tracking. Real time target tracking is the ideal method for treating moving lung tumors, but in its absence, ITV has been considered an acceptable alternative. Hobeika’s research confirmed that there is uncertainty in determining ITV density in patients, which reinforces the superiority of using real time tracking in the treatment of moving targets.

Research assistant professor Radka Stoyanova, Ph.D., is presenting her research focused on the use of advanced imaging techniques in radiotherapy. Dynamic contrast-enhanced imaging, diffusion weighted imaging and proton spectroscopy provide critical information about tumor location and its extent. Using powerful techniques for analysis of multi-parametric imaging data, the tumor volumes are delineated and transferred to the treatment planning station for boosting with a larger dose of radiation while sparing the surrounding normal tissues.

As part of a collaborative study with Pollack, Stoyanova, and other investigators, Jennifer Hu, Ph.D., professor of epidemiology and public health and associate director for prevention and control at Sylvester, will have an oral presentation on “Genetic Polymorphisms of DNA Repair and Inflammatory Responses in Late Toxicity of Prostate Cancer Patients Receiving Radiotherapy in a Randomized Trial.” This is the first pilot study of genetic factors in DNA repair and inflammatory responses related to genitourinary and/or gastrointestinal late toxicities in prostate cancer patients.

Hu’s laboratory also collaborated with Takita and Jean Wright, M.D., assistant professor of radiation oncology, in presenting two posters on “C-Reactive Protein Levels and Radiation-Induced Skin Reaction in Breast Cancer” and “Pre-treatment Oxidative Damage Associated with Early Adverse Skin Reactions from Adjuvant Radiotherapy in Breast Cancer Patients.” These are the largest studies of minority patients to show promising data on oxidative DNA damage and inflammatory markers in predicting radiotherapy-related skin toxicities in breast cancer patients.

Radiation oncology resident Kunal Saigal, M.D., is giving an oral presentation entitled “Pathologic Response and Locoregional Outcome in Post-Menopausal ER-Positive Breast Cancer Patients Receiving Neoadjuvant Endocrine Therapy Versus Cytotoxic Chemotherapy.” Saigal reports the outcome of patients treated with endocrine therapy prior to surgery, as an alternative to chemotherapy. In his study, he found that in post-menopausal women with estrogen receptor expressing breast cancers, the response to endocrine therapy is very similar to chemotherapy, but is naturally associated with decreased side effects. When these patients are followed over time, Saigal’s study notes that they are not at increased risk of tumor recurrence. His findings suggest that endocrine therapy prior to surgery may be a feasible alternative to chemotherapy in older women with estrogen receptor expressing breast cancers, and merits further evaluation.

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