Journal of Clinical Oncology, Vol 11, 351-359, Copyright © 1993 by American Society of Clinical Oncology
DNA ploidy and percent S-phase as prognostic factors in node-positive breast cancer: results from patients enrolled in two prospective randomized trials
TE Witzig, JN Ingle, DJ Schaid, LE Wold, JF Barlow, NJ Gonchoroff, JB Gerstner, JE Krook, CS Grant and JA Katzmann
Department of Internal Medicine, Mayo Clinic, Rochester, MN 55905.
PURPOSE AND METHODS: To help clarify the clinical utility of flow-
cytometric parameters, we performed flow cytometry on archival paraffin-
embedded primary breast cancers from 502 patients treated on two adjuvant
chemotherapy protocols performed by the North Central Cancer Treatment
Group (NCCTG) and Mayo Clinic. DNA ploidy and percent S-phase (%S) were
examined in univariate and Cox model multivariate analyses along with tumor
size, menopausal and estrogen receptor status, Quetelet's index (QI),
number of positive nodes and nodes examined, and Fisher and nuclear grades.
RESULTS: Ploidy analysis showed that 40% of tumors were DNA diploid and 60%
were DNA nondiploid (12% tetraploid and 48% aneuploid). There was no
difference in relapse-free survival (RFS) (P = .82) or overall survival
(OS) (P = .78) between the ploidy groups. Tetraploid patients had the
longest RFS and OS of any group, but this did not achieve statistical
significance. The %S was computed in 98% of cases and the medians were 9.0%
for all patients, 6.4% for diploid patients, and 11.7% for nondiploid
patients (P < .0001). By use of a %S greater than 12.3 as a prognostic
variable in a univariate analysis, there was a significant difference in
the RFS (P = .02) and OS (P = .007) of patients with low- versus
high-proliferative tumors. However, when the %S was adjusted for clinical
characteristics in the multivariate analysis, it was not a significant
factor for RFS (P = .23) or OS (P = .36). CONCLUSION: These results
indicate that DNA content and %S measurements by flow cytometry are not
clinically useful independent prognostic factors in women with resected
node-positive breast cancer administered adjuvant chemotherapy.
