The diffusion of a medical innovation: Variation in the utilization of breast conservation surgery

                         Jerome-D'Emilia, Bonnie Michele; PhD
                         VIRGINIA COMMONWEALTH UNIVERSITY, 1998

                         (0564); HEALTH SCIENCES, ONCOLOGY (0992)

                         In the past two to three decades, major changes have taken place in the surgical treatment of breast
                         cancer. In 1972, with the publication of early, randomized clinical trials, the modified radical mastectomy
                         became the gold standard treatment for early stage breast cancer. In the early 1980's the results of
                         several large-scale randomized clinical trials confirmed the efficacy of breast conserving procedures.
                         Many studies since that time have compared the relative rates of mastectomy to rates of breast
                         conservation surgery for stage I and II breast cancer. Although breast conservation is almost consistently
                         reported as underutilized, there have been no theoretical analyses reported that adequately address this
                         observation. This study has addressed two research questions. Can classical diffusion theory
                         appropriately characterize three distinct medical communities, defined as the academic medical center,
                         the non-academic teaching hospital, and the community hospital? And if so, can the varying rates of
                         diffusion of breast conservation found in the three categories of medical social system be explained by
                         diffusion theory? To address these questions, a number of diverse, theoretically derived variables were
                         used to characterize the three medical community types into groups defined by diffusion theory as
                         differing in their relative adoption potential. The relative rates of breast conservation to mastectomy were
                         then compared across a group of hospitals including each of the three types of medical communities.
                         Analysis of variance was used to test for differences between the three groups of hospitals. MuLtiple
                         regression analyses were then utilized to assess the factors most significant in determining the relative
                         rate of breast conservation surgery to mastectomy at each individual hospital. Results confirm that the
                         three groups of hospitals are separate and unique in terms of diffusion theory characteristics. Thus the
                         three groups of hospitals are consistent with the categories described in diffusion theory. Further, a
                         hospital's adopter group status was found to be a significant factor in explaining the relative rate of
                         diffusion of breast conservation in that hospital. A number of control variables were found to be
                         significant in previous research comparing the rates of mastectomy and lumpectomy. Some of these
                         variables, such as age, stage, income, and availability of radiation treatment, were found to be significant
                         in this study as well. Previous studies have attempted to explain the variation in the utilization of breast
                         conservation based on the appearance of one or more of this group of control variables. The addition of
                         the theoretically defined variable, adopter group status, which was significant for each of the two years,
                         1988 and 1994, tested separately, and for the two years over time, provides a theoretical explanation for
                         a consistently observed phenomenon. This explanation allows predictions to be made regarding the
                         diffusion of breast conservation surgery in the three types of medical communities, and solidifies
                         previous research on this topic into a coherent theoretical framework. Further research is necessary to
                         validate the applicability of diffusion theory in explaining the variation in breast conservation utilization.

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