Flow cytometry in primary breast cancer: improving the prognostic value of the fraction of cells in the S-phase by optimal categorisation of cut-off levels
Sigurdsson, H ; Baldetorp, Bo LU ; Borg, Åke LU ; Dalberg, M ; Fernö, Mårten LU ; Killander, Dick LU ; Olsson, Håkan LU
and Ranstam, J
(1990)
In British Journal of Cancer
62(5).
p.786-790
- Abstract
- The use of continuous prognostic variables is clinically impractical, and arbitrarily chosen cut-off points can result in a loss of prognostic information. Here we report findings from a study of primary breast cancer, showing how the prognostic value of the fraction of cells in the S-phase of the cell cycle (SPF), as measured by flow cytometry, can be affected by the SPF cut-off level(s) adopted. It was possible to evaluate the SPF in 566 (94%) of 603 consecutive cases where fresh frozen specimens were available in a tumour bank at our department. Clinically, all patients were without distant spread at the time of diagnosis, and the median duration of follow-up was 4 years. Using different survival end-points and chi 2 values for each... (More)
- The use of continuous prognostic variables is clinically impractical, and arbitrarily chosen cut-off points can result in a loss of prognostic information. Here we report findings from a study of primary breast cancer, showing how the prognostic value of the fraction of cells in the S-phase of the cell cycle (SPF), as measured by flow cytometry, can be affected by the SPF cut-off level(s) adopted. It was possible to evaluate the SPF in 566 (94%) of 603 consecutive cases where fresh frozen specimens were available in a tumour bank at our department. Clinically, all patients were without distant spread at the time of diagnosis, and the median duration of follow-up was 4 years. Using different survival end-points and chi 2 values for each cut-off level, two optimal cut-off points, at the 7% and 12% levels, were consistently obtained for the SPF. Furthermore, both disease-free survival and the relative risk of recurrence exhibited a non-linear relationship with SPF values; the curves implied that the prognosis was better among patients with SPF values about 2-5% than in patients with lower SPF values (parabolic shape), though the relationship with higher SPF values approached linearity. The non-linearity of the curves is incompatible with the general use of the median SPF as a prognostic cut-off value. An alternative procedure might be to use two cut-off levels, one to distinguish patients with the lowest SPF values (i.e. within the parabolic survival curve) from those with higher values (i.e. with a survival curve approaching linearity), the other to distinguish between patients with intermediate SPF values and those with high values (i.e. within the almost linear part of the survival curve). The 7% and 12% obtained here would be suitable for this purpose. We conclude that prognostic information can be gained by dividing the SPF into three prognostic categories (less than 7.0%, 7.0-11.9% and greater than or equal to 12%), instead of using the median SPF level. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1104995
- author
- Sigurdsson, H
; Baldetorp, Bo
LU
; Borg, Åke
LU
; Dalberg, M
; Fernö, Mårten
LU
; Killander, Dick
LU
; Olsson, Håkan
LU
and Ranstam, J
- organization
- publishing date
- 1990
- type
- Contribution to journal
- publication status
- published
- subject
- in
- British Journal of Cancer
- volume
- 62
- issue
- 5
- pages
- 786 - 790
- publisher
- Nature Publishing Group
- external identifiers
-
- pmid:2245171
- scopus:0025155515
- ISSN
- 1532-1827
- language
- English
- LU publication?
- yes
- id
- 10827352-9b44-4c8f-8624-fa4925513cd6 (old id 1104995)
- date added to LUP
- 2016-04-01 12:33:45
- date last changed
- 2021-02-14 05:57:59
@article{10827352-9b44-4c8f-8624-fa4925513cd6,
abstract = {{The use of continuous prognostic variables is clinically impractical, and arbitrarily chosen cut-off points can result in a loss of prognostic information. Here we report findings from a study of primary breast cancer, showing how the prognostic value of the fraction of cells in the S-phase of the cell cycle (SPF), as measured by flow cytometry, can be affected by the SPF cut-off level(s) adopted. It was possible to evaluate the SPF in 566 (94%) of 603 consecutive cases where fresh frozen specimens were available in a tumour bank at our department. Clinically, all patients were without distant spread at the time of diagnosis, and the median duration of follow-up was 4 years. Using different survival end-points and chi 2 values for each cut-off level, two optimal cut-off points, at the 7% and 12% levels, were consistently obtained for the SPF. Furthermore, both disease-free survival and the relative risk of recurrence exhibited a non-linear relationship with SPF values; the curves implied that the prognosis was better among patients with SPF values about 2-5% than in patients with lower SPF values (parabolic shape), though the relationship with higher SPF values approached linearity. The non-linearity of the curves is incompatible with the general use of the median SPF as a prognostic cut-off value. An alternative procedure might be to use two cut-off levels, one to distinguish patients with the lowest SPF values (i.e. within the parabolic survival curve) from those with higher values (i.e. with a survival curve approaching linearity), the other to distinguish between patients with intermediate SPF values and those with high values (i.e. within the almost linear part of the survival curve). The 7% and 12% obtained here would be suitable for this purpose. We conclude that prognostic information can be gained by dividing the SPF into three prognostic categories (less than 7.0%, 7.0-11.9% and greater than or equal to 12%), instead of using the median SPF level.}},
author = {{Sigurdsson, H and Baldetorp, Bo and Borg, Åke and Dalberg, M and Fernö, Mårten and Killander, Dick and Olsson, Håkan and Ranstam, J}},
issn = {{1532-1827}},
language = {{eng}},
number = {{5}},
pages = {{786--790}},
publisher = {{Nature Publishing Group}},
series = {{British Journal of Cancer}},
title = {{Flow cytometry in primary breast cancer: improving the prognostic value of the fraction of cells in the S-phase by optimal categorisation of cut-off levels}},
volume = {{62}},
year = {{1990}},
}