Sentinel Lymph Node Biopsy for Breast Cancer and Melanoma

US Oncological Disease, 2006;1(1):16-9

The hypothesis of the Florida Melanoma Trial (FMT) is that patients with a positive SLN who undergo CLND have no disease-free survival or overall survival advantage when compared to patients who have an SLNB alone, provided that all patients are also treated post-operatively with adjuvant interferon alpha-2b (IFN α−2b).This trial further stratifies patients based on the method of detection of metastases in the SLN, as determined by H&E, IHC, and by quantitative polymerase chain reaction (PCR).

The Sunbelt Melanoma Trial (SBMT) has a complex study design, with a total of seven arms in the randomization process. All patients with melanoma >1.0mm had SLN mapping and biopsy, with histologic analysis for micrometastases determined by H&E and IHC.All patients with a histologically positive SLN had CLND, and then patients were further randomized to either observation or adjuvant IFN α-2b. This part of the trial will determine the role of adjuvant IFN α-2b in patients with minimal nodal disease. Patients who had a histologically negative SLN then had further molecular analysis of the node by PCR. Patients with a PCR negative node will be observed, but those with a PCR positive node were randomized to observation, CLND, or CLND with IFN α-2b.This part of the trial will determine the value of molecular staging by PCR, and will determine the optimal treatment for patients upstaged by PCR.

Clinical Trials Involving SLNMapping for Breast Cancer
Three prospective, randomized clinical trials are evaluating SLNB in women with breast cancer. The National Surgical Adjuvant Breast and Bowel Project (NSABP) B-32 opened in 1999 and randomized women with clinically node-negative early-stage breast cancer to undergo SLNB alone, or SLNB with mandatory ALND. For patients randomized to the SLNB-alone arm, if the node was positive then an ALND was offered.The goal of the NSABP B-32 trial is to determine the value of SLNB alone compared to SLNB followed by ALND for patients with a histologically negative SLN.

Conclusion
Sentinel lymph node mapping and biopsy is a relatively new technique for staging and treating patients with melanoma or breast cancer.With tremendous benefits and minimal risk, SLNB has become so widely adopted that elective lymph node dissections are practically antiquated. Although this procedure has a learning curve, most surgeons who treat breast cancer and melanoma have been able to incorporate this technique into their practice.

Results from the clinical trials presented in this article will answer many questions about SLN mapping and will likely change the management of these diseases significantly over the next few years.A multidisciplinary team approach will certainly help physicians evolve as novel therapies and treatment algorithms are developed.

ACRO Meeting Focuses on Successes and Challenges for Radiation Oncologists`
The American College of Radiation Oncology (ACRO) held its 16th annual meeting at Disney’s Contemporary Resort in Orlando from February 23–25, 2006. The meeting’s program reflected the state of the field, including recent advances and current challenges.

Educational Program
Brian Kavanagh, MD, from the Anschutz Cancer Pavilion in Aurora, CO, explained the historical development and basic concepts of stereotactic body radiation therapy. John Kresl, MD, PhD, from St Joseph’s Hospital in Phoenix, AZ, followed with a review of robotic radiosurgery, pointing out its ability to correct continuously for patient and target motion. Then Anjit Singh, PhD, from Siemens Medical Solutions, gave an overall perspective of adaptive radiotherapy, showing how radiation oncologists must approach the problem of treating a tumor that changes its location and shape.

Intensity-modulated radiation therapy (IMRT) was also a hot topic. Arno Mundt, MD, from the University of Chicago, IL, suggested that gynecologic IMRT could be an alternative to brachytherapy for cervical and endometrial cancers. Seymour Levitt, MD, from the University of Minnesota, extolled advances in targeting radiotherapy, but warned ACRO members to be aware of the limitations of IMRT. He and Clifford Chao, MD, from the M D Anderson Cancer Center in Houston, TX, reminded meeting attendees that they needed to have the proper expertise to handle the targeting. In addition, the University of Alabama’s Ruby Meredith, MD, PhD, described clinical trials to evaluate radiolabeled antibody therapy, especially as it relates to non-Hodgkin lymphoma. Roger Macklis, MD, from the Cleveland Clinic, OH, noted how radioimmunotherapy must involve cooperative efforts between radiation oncologists and those in nuclear medicine.

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