Measuring radiation fibrosis: the interobserver reliability of two methods of determining the degree of radiation fibrosis.

Abstract

To compare the interobserver reliability of the palpation method with the method of measuring tissue compliance with a tissue compliance meter (TCM) on women who underwent breast-conserving surgery and radiotherapy for breast cancer. Thirty-eight patients and 30 controls were measured with the palpation method by two radiation oncologists and with the TCM by two physiotherapists. Measurements were taken on four locations of the breasts of all 68 women. Reliability coefficients were computed for both methods. A weighted kappa score was computed for the palpation method and this was compared with the intraclass correlation coefficient (ICC) computed for the TCM method. The conditions for direct comparison of these scores were met in this study. A weighted kappa of 0.65 was computed for the palpation method and an ICC of 0.91 was computed for the TCM method. These scores differ significantly from each other (p < 0.01). The interobserver reliability of the TCM method is superior to that of the palpation method. However, at locations where the TCM is not applicable, palpation is a good alternative.