Relationship of DNA ploidy and S-phase fraction to survival after first recurrence of breast cancer.

Flow cytometry was performed on frozen specimens from the primary tumour of 184 women with recurrent breast cancer. No significant association was seen between DNA ploidy and the other prognostic factors investigated. Patients with a high S-phase fraction had more often a negative estrogen receptor (ER) status and a short disease-free interval. A shorter survival after disease recurrence was seen both in patients with DNA aneuploid tumours and among those with a high S-phase fraction. Patients with DNA tetraploid tumours showed the longest survival after recurrence. In this subgroup, half of the patients survived more than 3 years after recurrence and the estimated survival rate at 10 years was 17%. In a Cox's regression analysis including 116 patients, site of recurrence, number of positive nodes at time of primary operation, size and ER content of the primary tumour as well as DNA ploidy showed additional prognostic value.