An evaluation of techniques used in superficial radiotherapy for non-melanoma skin cancer to replicate the planned treatment area: A prospective study

• Published in: Radiography (London, England. 1995) England. 1995), 2019-11, Vol.25 (4), p.280-287
• Main Authors: Vassiliou, M., Callender, J., Manning-Stanley, A.S.
• Format: Article
• Language: English
• Subjects: Non-melanoma skin cancer; Superficial radiotherapy; Technique replication
• ISSN: 1078-8174; 1532-2831
• DOI: 10.1016/j.radi.2019.04.010

Accuracy of superficial radiotherapy for non-melanoma skin cancer is dependent on replicating the original clinical mark-up. Responses from 18 UK Radiotherapy centres identified the four most common replication techniques; the accuracy and time-efficiency of each was evaluated, as well as participant preference and confidence. A 2.0  cm × 2.5  cm ellipse field was drawn around the nasal ala of a surrogate patient. Templates for each replication method (1–4) were created, and skin marks removed. Twenty-five therapeutic radiographers used each method to replicate the mark-up. Measurements were recorded for lateral and longitudinal displacement, ellipse diameter and time taken. A post-study questionnaire recorded participant preference and perceived confidence. Comparison of the mean ellipse areas for methods 1–4 identified no statistically significant differences (ANOVA test; p = 0.579 to p = 0.999). Lateral and longitudinal displacements for method 1–4 showed a statistically significant difference between method 3 and each of methods 1, 2, 4 for lateral and longitudinal respectively (ANOVA; lateral: p = 0.008, p = 0.002, p = 0.05; longitudinal: p = 0.036, p = 0.000, and p = 0.000). Mean time taken was longest for method 3, and was compared using a Friedman test (p = 0.000) identifying a statistically significant difference. Twenty-two participants completed the questionnaire. 48% favoured method 2, 41% method 4. Method 3 was least favourite. A Likert scale (1–10) measured confidence. Participants had most confidence in methods 2 and 4. In this study, method 3 was least accurate, most time consuming, and was least favoured by users. The clinical significance of these results will depend on the margins used in local practise. •Variation exists in replication methods for a superficial radiotherapy technique between treatment centres in the UK.•The least accurate and most time consuming method in the study was method 3 (use of annotated photographs).•Method 3 was also least preferred by, and instilled the least confidence in, radiographers during the study.•Methods 2 (acetate template) and 4 (partial thermoplastic mask) were most preferred and instilled most confidence.