The ‘1984 McIndoe’ Paper

In 1966, the management of the academic department of Obstetrics and Gynaecology of The University of Auckland located at National Women’s Hospital formalised a proposal for prospective research into the ‘natural history’ of Carcinoma in situ (CIS) of the cervix. The study was to examine whether women diagnosed with CIS of the cervix went on to develop invasive cancer.

In 1984, William McIndoe, the colposcopist at the hospital, Malcolm Mclean the pathologist, and gynaecologist Ron Jones published a paper in the prestigious journal Obstetrics and Gynecology with the help of Auckland University statistician Peter Mullins, which provided a retrospective analysis of the results.

They reviewed the cases of 948 patients at National Women’s Hospital who had had a diagnosis of CIS confirmed by histology between 1955 to 1984. Histology, which is the microscopic examination of slides of tissue removed by biopsy from the relevant lesion, provides the definitive diagnosis for CIS.
As was normal medical practice at the time, most of the cases examined had been identified by a positive result from a cytological smear test. In conventional management of the condition it was usual to follow treatment with further smear tests. If the results of such test returned to normal, it was presumed that this indicated that the lesion had been eradicated.
For the purposes of analysis, McIndoe and his collaborators divided the women into two groups. One group of 817 women consisted of those whose smears were consistently normal after two years. A second group, containing 131, comprised those women who continued to have abnormal smears, which suggested that abnormalities remained. This second group contained some women who had only received diagnostic biopsies and had not been offered curative treatment.

The study found very significant differences in the extent to which the two groups progressed to invasive cancer. In group one, 12 women or 1.5% developed invasive cancer. In the second group, 29 women or 22% developed invasive cancer. A subgroup of this second group received only ‘small incomplete diagnostic biopsies and observation alone’. Ten of these women continued to have positive cytology and 80% of them developed invasive cancer.

The study, thus, showed that CIS, if it was not eradicated, potentially led to invasive cancer of the cervix or vaginal vault in a significant number of patients. The paper did not attract a great deal of medical comment. Its content, however, suggested that some patients had been diagnosed but not treated. When this paper was drawn to the attention of Sandra Coney and Phillida Bunkle they investigated this implication further.