Discussion
In this study, we examined efficacy of application of glucocorticosteroid during patch occlusion and subsequently silicone gel sheet. We hypothesized that the combination of glucocorticosteroid and patch occlusion would be effective in reducing the development of hypertrophic scar/keloid after removal of CVC on children and adolescents treated for neoplastic diseases. We also expected that scar width and children’s or their parents’ subjective perception of the scar would be improved by using glucocorticosteroid during patch occlusion.
The results of the VSS assessed by the study nurse were different from the data from the dermatologist. The study nurse generally assessed VSS higher than the dermatologist. The VSS is developed to rate burn scars, but it also has an acceptable internal consistency for linear scars (Chronbach´s alpha 0.79). The inter-observer reliability is found substantial (Intraclass coefficient correlation 0.78) [10]. However, Truong et al. do not describe whether the observer using the VSS should have dermatological experience [10]. In the present study, the study nurse was specialized in pediatric oncology as opposed to the dermatologist, who had considerable experience in assessing scars. Therefore, data from the dermatologist are considered to be the most reliable.
Data from the dermatologist showed that the intervention group had a lower VSS score than the control group 12 months after removal of the CVC. Common for the two groups in the intervention group (active and placebo) was the use of sheet occlusion. Both groups had cream applied under patch occlusion one week before, and three weeks after removal of the CVC. After three weeks, both groups covered their scar with a silicone gel sheet for three months, to avoid pull on the scar. Since the cream received by the two groups was different (placebo and glucocorticosteroid), the significant lower VSS score may be caused by the sheet. Future studies may be able to detect the effect more robustly by including more patients in the intervention groups.
By searching the literature, we found only two papers on CVC cars in children with cancer. Braam et al. (2015) [6] performed a three-arm randomized controlled trial. The aim of the study was to evaluate the effects of using silicone gel sheets on scar outcome after removal of PAC on children with cancer. Two intervention groups were included; One received two months of silicone gel sheets application, and one received six months of silicone gel sheet application. The control group received no additional care or treatment. No significant improvement of scar outcome was found when using silicone gel sheets after the PAC removal. A small benefit for scar width with application for two months was found [6]. In the present study, both the active and the placebo groups used a silicone gel sheet for three months and had a better outcome than the control group. Overall, the intervention group had a significantly lower VSS score than the control group (p = 0.00). This is supported by a review investigated the effectiveness of silicone gel and silicone gel sheeting for the prevention of hypertrophic or keloid scarring on patients with newly healed wounds. However, they also found that most of the trials had poor quality with high or uncertain risk of biases in the design or the conduct [7]. Overall, there is a need for larger studies and interventions that can distinguish between the effect of silicone gel sheet and the effect of glucocorticosteroid in combination with silicone gel sheet.
The POSAS was in combination with the VSS used to assess the scars. The POSAS consists of an extra dimension because the patients´ opinion is required for a complete scar evaluation. The patients’ opinion does not figure in the VSS. The POSAS assessed by the patients and the study nurse showed that the intervention group had a lower score than the control group, which is consistent with the results for the VSS assessed by the dermatologist. However, the differences in the POSAS was not significant.
The results should be interpreted with caution due to the study limitations. The study included a relatively small sample size in the intervention group. A total of 69 patients were assessed for eligibility, 33 patients were excluded inter alia due to failure to follow the recommended treatment and relapse. This must be expected when working with children with cancer.
Another limitation is the fact that the 47 patients in the control group were collected retrospectively. Therefore, we cannot exclude that the parents applied a patch in the period following removal of the CVC, but it was not part of the recommendations from the department. No record was made whether children covered their scar with a patch after removal of the CVC. But the probability that they have used a patch with silicone gel seems small, both because it is not a standard patch and because it is expensive.
Furthermore, most of the participants had a PAC, which limits the conclusions that can be derived concerning tunnelled central venous catheter.