Canadian Cancer Trials Group Bulletins


Primary Results of NCIC SC.20 Published by Lancet Oncology

Canadian Cancer Trials Group SC.20 -- A Phase III International Randomized Trial of Single versus Multiple Fractions for Re-Irradiation of Painful Bone Metastases

The primary results of Canadian Cancer Trials Group SC.20, presented at the 2013 American Society of Clinical Oncology Annual Meeting and recently published online by Lancet Oncology, show that radiation treatment can help relieve painful bone metastases even when previous radiation treatment has been given. Furthermore, it is believed that most patients will benefit from a single radiation treatment as compared with treatment that is given daily for 5 or more days.

The trial compared pain relief in patients with symptomatic bone metastases who had previously received radiation treatment; patients were allocated to receive radiation treatment with 8 Gy in a single fraction (i.e. 1 day of treatment) or 20 Gy in multiple fractions (5 days of treatment for most patients and 8 days of treatment for some patients with bone metastases to the spine or the pelvis). The aim was to determine if the simpler therapy administered over one day was as effective and might have fewer side-effects as compared with more complex treatment administered over multiple days.

The primary endpoint of the trial was pain relief assessed using the International Consensus Endpoint, which uses a questionnaire, referred to as the Brief Pain Inventory, to score pain and accounts for changes in doses of narcotic pain medications. This endpoint was assessed two months after radiation treatment was started. To be considered to have benefited from repeat radiation, a patient's pain either had to be alleviated with no associated increase in narcotic dose, or the pain control had to be as good as prior to radiation with the dose of narcotics being reduced. Secondary endpoints included the frequency and severity of side effects, patient-reported quality of life, the frequency of bone fractures or compression of the spinal cord and overall survival.

Between 2004 and 2012, 850 patients were enrolled from 9 countries, including Canada and the United States. Because not all patients could be evaluated two months after radiation treatment, two analyses were performed. The first, referred to as an intent-to-treat analysis, considered any patients with unavailable data at two months to have not benefitted from radiation treatment. The second analysis, referred to as a per-protocol analysis, compared only those patients with available data. In the intent-to-treat analysis, a benefit from radiation therapy was observed in 28% of those treated with 8 Gy in a single day and in 32% of those treated with 20 Gy given over multiple days. These results met pre-determined criteria for declaring that the single fraction was non-inferior to multiple treatments. In the per-protocol analysis, a benefit from radiation therapy was observed in 45% of those treated with 8 Gy in a single day and in 51% of those treated with 20 Gy given over multiple days. By this analysis, the pre-determined criteria for non-inferiority were not met. Those receiving 20 Gy given over multiple days experienced more side-effects, including skin reddening, nausea, lack of appetite, vomiting and diarrhea. The overall survival of the two groups was identical.

'The results of our study show that repeat radiation therapy can be an important treatment for patients with pain from bone metastases' said the lead study author Dr. Edward Chow, MD, from the Sunnybrook Odette Cancer Centre and University of Toronto. 'We believe that most patients are equally well served with treatment given in a single day instead of over five or more days. This treatment is also easier for patients and has fewer side-effects.'

Chow E, van der Linden YM, Roos D, Hartsell WF, Hoskin P, Wu JSY, Brundage MD, Nabid A, Tissing-Tan CJA, Oei B, Babington S, Demas WF, Wilson CF, Meyer RM, Chen BE, Wong RKS. Single versus multiple fractions of repeat radiation fo ed, controlled, non-inferiority trial (ONLINE). The Lancet Oncology 2013.

These results were also profiled by Reuters Health which is available using this link ...

Dr. Ed Chow Congratulations and thanks go to Dr. Edward Chow, lead investigator, and to the many other investigators, centres, staff and patients who contributed to the successful completion and reporting of this study.