Objective: To investigate whether breast carcinomas found to be DNA diploid by flow cytometry (FCM) are still diploid if reassessed by image cytometry (ICM).
Study design: In a series of 286 breast cancers analyzed by FCM there were 100 (35%) cancers that were classified as DNA diploid. Fourteen of the 100 diploid cases were selected for further analysis with ICM because the patient had died of breast cancer within 11-84 months after the diagnosis (a group with unfavorable outcomes), and 19 cases were selected at random from the cases who had no recurrence of cancer during follow-up of six or more years (a favorable group).
Results: Eleven (33%) of the 33 cases turned out to be DNA nondiploid, with a DNA index > or = 1.2 when analyzed by ICM. Nine of the 11 DNA aneuploid samples by ICM were found among the 14 patients with unfavorable prognoses and only 2 among the 19 patients with favorable outcomes (P = .002). The five-year survival rate of the women with DNA diploid cancer by both methods was 86%, whereas that of patients with DNA aneuploid cancer by ICM was 36% (P = .002).
Conclusion: The results show that some breast carcinomas classified as DNA diploid based on FCM are not DNA diploid by ICM and that such carcinomas are associated with poorer outcomes than the ones that are DNA diploid also by ICM. The prognostic significance of DNA ploidy in breast cancer may need to be reexamined in studies where both FCM and ICM are used.