Identifying barriers to accrual in radiation oncology randomized trials.

BACKGROUND: Data about factors driving accrual to radiation oncology trials are limited. In oncology, 30%-40% of trials are considered unsuccessful, many because of poor accrual. The goal of the present study was to inform the design of future trials by evaluating the effects of institutional, clinician, and patient factors on accrual rates to a randomized radiation oncology trial. METHODS: Investigators participating in sabr-comet (NCT01446744), a randomized phase ii trial open in Canada, Europe, and Australia that is evaluating the role of stereotactic ablative radiotherapy (sabr) in oligometastatic disease, were invited to complete a survey about factors affecting accrual. Institutional ethics approval was obtained. The primary endpoint was the annual accrual rate per institution. Univariable and multivariable linear regression analyses were used to identify factors predictive of annual accrual rates. RESULTS: On univariable linear regression analysis, off-trial availability of sabr (p = 0.014) and equipoise of the referring physician (p = 0.014) were found to be predictive of annual accrual rates. The annual accrual rates were lower when centres offered sabr for oligometastases off-trial (median: 3.7 patients vs. 8.4 patients enrolled) and when referring physicians felt that, compared with having equipoise, sabr was beneficial (median: 4.8 patients vs. 8.4 patients enrolled). Multivariable analysis identified perceived level of equipoise of the referring physician to be predictive of the annual accrual rate (p = 0.023). CONCLUSIONS: The level of equipoise of referring physicians might play a key role in accrual to radiation oncology randomized controlled trials. Efforts to communicate with and educate referring physicians might therefore be beneficial for improving trial accrual rates.

The Canadian Association of Radiation Oncology scope of practice guidelines for lung, liver and spine stereotactic body radiotherapy.

AIMS: The Canadian Association of Radiation Oncology-Stereotactic Body Radiotherapy (CARO-SBRT) Task Force was established in 2010. The aim was to define the scope of practice guidelines for the profession to ensure safe practice specific for the most common sites of lung, liver and spine SBRT. MATERIALS AND METHODS: A group of Canadian SBRT experts were charged by our national radiation oncology organisation (CARO) to define the basic principles and technologies for SBRT practice, to propose the minimum technological requirements for safe practice with a focus on simulation and image guidance and to outline procedural considerations for radiation oncology departments to consider when establishing an SBRT programme. RESULTS: We recognised that SBRT should be considered as a specific programme within a radiation department, and we provide a definition of SBRT according to a Canadian consensus. We outlined the basic requirements for safe simulation as they pertain to spine, lung and liver tumours, and the fundamentals of image guidance. The roles of the radiation oncologist, medical physicist and dosimetrist have been detailed such that we strongly recommend the development of SBRT-specific teams. Quality assurance is a key programmatic aspect for safe SBRT practice, and we outline the basic principles of appropriate quality assurance specific to SBRT. CONCLUSION: This CARO scope of practice guideline for SBRT is specific to liver, lung and spine tumours. The task force recommendations are designed to assist departments in establishing safe and robust SBRT programmes.

Photochemical keratodesmos for repair of lamellar corneal incisions.

PURPOSE: To determine the efficacy of photochemical keratodesmos (PKD) for closing surgical incisions in the cornea of enucleated rabbit eyes compared with that achieved using sutures and self-sealing incisions. METHODS: A 3.5-mm incision, at an angle parallel to the iris, was made in the cornea of enucleated New Zealand White rabbit eyes. The intraocular pressure required to cause leakage (IOP(L)) from the untreated incision was then recorded. Photochemical keratodesmos treatment was then performed by application of a dye, Rose Bengal (RB), in saline solution to the surfaces of the incision wound, followed by laser irradiation at 514 nm from an argon ion laser. Immediately after treatment, the IOP(L) was measured. Both dose and laser irradiance dependencies were studied in five or more eyes for each condition and appropriate control eyes. The IOP(L)s were compared with those obtained using conventional interrupted 10-0 nylon sutures. Other dyes were tested in a similar fashion. RESULTS: The IOP(L) of 300 mm Hg was obtained using a fluence of 1270 J/cm(2) with an irradiance of 1.27 W/cm(2) (laser exposure time, 16 minutes 40 seconds). No sealing was observed using dye or light alone where control pressures of approximately 30 mm Hg were found. At higher dose (1524 J/cm(2)) and irradiance (3.82 W/cm(2); 6 minutes 35 seconds), PKD was less effective, which may be attributable to thermal effects. PKD produced IOP(L)s similar to those in closure by sutures. Other dyes such as riboflavin-5-phosphate and N:-hydroxy-pyridine thione also produced efficient bonding after PKD. Nonphotochemically active dyes did not produce significant increases in the IOP(L) at which leakage occurred. CONCLUSIONS: The increase in IOP(L) after PKD treatment, comparable with that with sutures, in enucleated rabbit eyes demonstrates the feasibility of this technique ex vivo.