Advice
Clinical and technical evidence
Clinical and technical evidence
A literature search was carried out for this briefing in accordance with the published process and methods statement. This briefing includes the most relevant or best available published evidence relating to the clinical effectiveness of the technology. Further information about how the evidence for this briefing was selected is available on request by contacting mibs@nice.org.uk.
Published evidence
Six studies (table 1) were selected for inclusion in this briefing. These included 452 patients, with follow-up ranging from 1 to 5 years. The studies were reported in 1 full-text paper and 5 conference abstracts, so information was limited. All of the studies included patients with breast cancer classed as ductal carcinoma in situ (DCIS) which is not currently an Oncotherapy Resources-recommended indication for treatment with Axxent eBx. Ivanov et al. (2011) justified the inclusion of patients with DCIS, stating that the rate of recurrence in this group is high enough to warrant SD‑IORT. In addition, 4 of the 6 studies included patients who are younger than those for whom Oncotherapy Resources recommends SD‑IORT.
Overall the studies reported on the following outcomes: recurrence, adverse events and cosmetic outcomes. No recurrences were reported at 1‑year follow-up, but at 5 years Dickler et al. (2015) reported 4 recurrences in 68 patients. This was stated to be comparable to accelerated partial breast irradiation. In general, SD‑IORT with the Axxent eBx system was well tolerated with a low rate of adverse events and positive cosmetic outcomes.
Table 1 summarises the clinical evidence, and its strengths and limitations.
Table 1: Included studies of SD‑IORT with the Axxent eBx system
|
Study |
Details of intervention [and comparator] |
Outcomes |
Strengths and limitations |
|
22 patients, 18 enrolled Prospective case series Single centre US Follow-up: 1 year (median) |
Xoft Axxent electronic brachytherapy system. Single dose of 20Gy. |
No grade 3 to 4 adverse events. Cosmetic outcome was excellent in most patients. No local recurrence. One patient needed whole breast irradiation due to close margins at re-excision. |
Strengths: Prospective study. Limitations: Conference abstract only; case series; single centre; included patients with DCIS which is not a recommended criteria for treatment with SD‑IORT; longer follow-up would allow recurrence to be fully assessed. |
|
30 patients Retrospective case series Single centre Portugal Follow-up: 18 months (median) |
Xoft Axxent electronic brachytherapy system. Single dose of 20 Gy. |
Mean treatment time of 9 minutes 10 seconds. No grade 3 to 4 adverse events. No local recurrence, 1 axillar recurrence 1 year post-treatment. |
Limitations: Conference abstract only; retrospective; single-centre case series; included patients <50 years of age which is not a recommended criteria for treatment with SD‑IORT; longer follow-up would allow recurrence to be fully assessed. |
|
68 patients with 69 breast cancers Prospective case series Multicentre (n=not reported) US Follow-up: 5 years |
Xoft Axxent electronic brachytherapy system. Single dose of 20 Gy. |
Mean time to deliver the radiation was 13 minutes (range 7 to 30 minutes). No grade 4 to 5 adverse events. Cosmetic outcomes were excellent or good in most patients. Four local recurrences occurred. |
Strengths: Multicentre study, 5‑year follow-up. Limitations: Conference abstract only, case series; included patients with DCIS and of <50 years of age which are not recommended criteria for treatment with SD‑IORT. |
|
78 patients Prospective case series Multicentre (n=12) US Follow-up: 12 months (median) |
Xoft Axxent electronic brachytherapy system. Single dose of 20 Gy (n=77), 21 Gy (n=1). |
Mean treatment time was 10.5 minutes. A low rate of adverse events. Cosmetic outcomes were excellent or good in most patients. |
Strengths: Multicentre study Limitations: Conference abstract only; case series; included patients with DCIS and of <50 years of age which are not recommended criteria for treatment with SD‑IORT; longer follow-up would allow recurrence to be fully assessed. |
|
11 patients Prospective case series Single centre US Follow-up: 12 months (mean) |
Xoft Axxent electronic brachytherapy. Single dose of 20 Gy. |
Mean time for radiation delivery was 22 minutes (range 20 to 24 minutes). At 12-month follow-up, 10/11 patients rated overall cosmesis as excellent. Cancer recurrence did not occur within follow-up period. Potential adverse events such as rib fracture, infection, fat necrosis or desquamation did not occur. |
Strengths: Prospective study Limitations: Case series; small sample size; single centre; included patients with DCIS which is not a recommended criteria for treatment with SD‑IORT; longer follow-up would allow recurrence to be fully assessed. |
|
243 patients Prospective case series Multicentre (n=17) US Follow-up: 16.5 months (median) |
Xoft Axxent electronic brachytherapy system. Single dose of 20 Gy (n=242), 21 Gy (n=1). |
The mean treatment time was 10.2 minutes. A low rate of adverse events. Cosmesis was excellent to good in most patients. |
Strengths: Multicentre study Limitations: Conference abstract only; case series; included patients with DCIS and of <50 years of age which are not recommended criteria for treatment with SD‑IORT; longer follow-up would allow recurrence to be fully assessed. |
Strengths and limitations of the evidence
There is a lack of robust published evidence evaluating SD‑IORT for early‑stage breast cancer using the Axxent eBx system. The studies identified in this briefing were all non-comparative. However, there are 2 ongoing trials that are likely to provide further data when completed: Syed 2016 is a multicentre trial of 243 patients and Dickler 2015 reports 5‑year follow-up data.
Recent and ongoing studies
A search of Clinicaltrials.gov and the WHO International Clinical Trials Registry Platform for 'XOFT OR Axxent AND breast' found the following 3 results:
-
Intraoperative radiation therapy immediately following resection of early stage breast cancer. Status: active; not recruiting; enrolled 75; preliminary results published in Dickler et al 2015. Indications: breast cancer.
-
Intraoperative radiotherapy for early stage breast cancer. Status: active; target of 200; not recruiting. Indications: breast cancer.
-
Safety and efficacy study of the Xoft Axxent eBx IORT System. Status: Recruiting; target of 1200; preliminary results published in Syed et al. 2016. Indications: invasive ductal carcinoma; DCIS.