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ASTRO: HOT OFF THE PRESS

SAN FRANCISO, CA – The 56th Annual Meeting of the American Society for Radiation Oncology (ASTRO) was in high gear this week. A record number of abstracts were submitted (n=2874); 2370 abstracts were presented, among these were 364 oral scientific sessions. More than 10,000 people from around the world attended the meeting, according to 2014 ASTRO President, Bruce T. Haffty, MD.

At the opening press conference, Dr. Haffty highlighted three important initiatives of ASTRO – participation in the ABIM’s Choosing Wisely® campaign, the Stereotactic Radiosurgery (SRS) patient registry, and the Radiation Oncology Incident Learning System (RO-ILS).

ASTRO unveiled its second list of 5 radiation treatments to question for routine use as part of Choosing Wisely®; these treatments/procedures should be thoroughly discussed by physicians with their patients to ensure appropriate use.

In 2013, ASTRO issued its first list of 5 such treatments, and the good news is that this effort is beginning to pay off in clinical practice, conserving resources for appropriate use, informed Dr. Haffty.

To find all 10 treatments that should be questioned before prescribing them go to: www.choosingwisely.com.

The Stereotactic Radiosurgery (SRS) patient registry is a partnership between ASTRO and the American Association of Neurologic Surgeons (AANS). SRS purports to gather data from 30 diverse high-volume sites, with data specific to SRS, over the next 3 years. This national registry will define patterns of care in radiosurgery, and hopefully support informed decision-making to improve outcomes and possibly lower the costs of care for patients.

The RO-ILS program sponsored jointly by ASTRO and the American Association of Physicists in Medicine (AAPM) is a patient-safety initiative that is the centerpiece of ASTRO’s Target Safely plan.  Radiologists are invited to submit data on radiation mishaps anonymously to give the radiation community a heads-up about potential problems and enable detection of patterns of safety.

“The anonymity provides confidentiality and creates a secure environment,” Dr. Haffty said. “Radiation is an extremely safe modality. Nonetheless, we want to strive for zero errors and review mistakes.”

Selected highlights from the Clinical Trials session include the following:

  • A study showing that radiation therapy was as effective as chemoradiation in reducing the incidence of dysphagia for patients with advanced esophageal cancer in the palliative setting (Abstract CT-03). This finding suggests that this patient population can avoid chemotherapy, its side effects and costs.
  • Convincing evidence showed that adding thoracic radiotherapy to prophylactic whole brain irradiation extends survival and reduces local recurrence in patients with advanced small-cell lung cancer (Abstract CT-05).
  • A very large study of more than 41,000 patients found that radiation improves 10-year survival by 50% in patients with early stage Hodgkin’s disease, yet radiation remains highly under utilized in this population in the U.S. (Abstract CT-08).  Medical oncologists are apparently not suggesting radiation because of perceived fears about long-term side effects.
  • Hypofractionated whole breast irradiation reduces acute toxicity and long-term fatigue compared with conventional fractionation in patients with stage 0-II breast cancer undergoing breast conserving therapy (Abstract LBA 3). Again, fears of side effects with a more concentrated dose of radiation delivered over a shorter time period have limited adoption of hypofractionated regimens.

Highlights of the Plenary Session

This included a talk centered on the ability of radiotherapy to induce antigen-specific immune responses when combined with anti-PD-1 blockade (Abstract PL-01). These preclinical data were selected for prime time presentation because of the intense interest in immunotherapy in the oncologic community with the recent successes in advanced melanoma.

Another Plenary Session talk showed that 28 months of androgen deprivation therapy (ADT) combined with high-dose radiation therapy improved biochemical control rates and survival compared with only 4 months of ADT plus high-dose radiation in patients with intermediate and high-risk localized prostate cancer. (Abstract PL-02). The benefit of prolonged ADT was seen mainly in high-risk patients.

This study adds to evidence that longer than 6 months or 1 year of ADT is needed to reap the survival benefits of this difficult-to-tolerate therapy.  A separate study, not presented at the plenary, showed that 18 months of ADT was just as effective as 36 months and improved quality of life when combined with radiation in this setting (Abstract 24). The optimal duration of ADT plus radiation remains to be established with certainty, but for now, longer than 12 months is better.

A separate Plenary Session presentation demonstrated that one high-dose of radiation therapy was as effective as more frequent lower doses of radiation in preserving mobility in patients with malignant spinal cord compression who cannot undergo decompression surgery (Abstract LBA 2). These patients have a miserable prognosis, with a neurological deterioration-free survival time of 1.4 months and an overall survival of just 4 months.

Other news of note is the development of a 10-gene signature to predict radiation sensitivity in a variety of solid tumors. This signature is treatment-specific rather than disease-specific, as distinct from genetic signatures for OncotypeDX or MammaPrint assays.

The signature was the subject of 10 presentations at ASTRO, and featured at a Panel Discussion (Abstracts 2463 2224, 2615, 1246, 2649, 2899, 3633, 3916, 1420, 1031, and 2873).

So far, the genetic signature has been tested and correlated with clinical outcomes in rectal, lung, esophageal, and brain cancer, as well as and metastatic colorectal and prostate cancers.

The signature is the brainchild of Javier Torres-Roca, MD, Moffitt Cancer Center in Tampa, FL, and it took 11 years to develop, he said. He believes the signature will be clinically actionable – showing that higher doses of radiation are needed in resistant patients (according to the signature) and reducing radiation doses in sensitive patients.

The signature is a joint venture with the NCI, Moffitt Cancer Center, and the Asan Medical Center in Korea. A company called CvergenX, founded by Dr. Torres-Roca and colleague Stephen Eschrish, PhD, has the license to market it, once it is CLIA or FDA approved.

By John McCleery

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