Unintended overexposure of a patient during palliative radiotherapy treatment: investigation report

Covering note

It is notable that this report follows closely on a report published by the Scottish Ministers in 2016 on an 'Unintended overexposure of a patient during palliative radiotherapy treatment at the Edinburgh Cancer Centre' (http://www.gov.scot/Publications/2016/07/8854/1) in September 2015.

It should be stressed, however, that the nature of the errors considered here and in this earlier report was quite different.

The particular circumstances of the September 2015 incident were that the treatment was appropriately prescribed by the practitioner in accordance with the applicable Edinburgh Cancer Centre (ECC) treatment protocol, but errors were made in the subsequent process of calculating how the prescribed treatment was to be delivered. The result was that the treatment was delivered to the correct target volume but at twice the intended dose of radiation.

In the incident considered in this report, the error again occurred at the stage of treatment planning, but in this instance in defining the target volume. The result was that the dose of radiation delivered to the patient was correct but was delivered to the wrong target volume.

The finding of this report is, therefore, that the most likely cause of this incident was an error by an individual in the process of defining the target area, rather than any identifiable planning miscalculation or error of clinical judgement.

In no sense, therefore, should the close occurrence of these two incidents be construed as suggesting a systemic weakness in treatment planning at the ECC.

However, it is apparent from this investigation that staffing and workload pressures were a contributory factor in this incident, and such pressures are not confined to the ECC. This highlights again the need for effective workload management to ensure that staff performance is not unduly compromised by predictable instances of excessive demand.

Many thousands of life-saving radiotherapy treatments are successfully prescribed, planned and delivered at the ECC and at the other radiotherapy centres in Scotland every year. The occasional appearance of reports such as this should therefore be regarded as reassuring evidence of the transparency of the provisions that are in place to identify, investigate, and address any concerns arising from these very occasional incidents.

Dr Arthur M Johnston
Warranted Inspector appointed by the Scottish Ministers