THE RETROSPECTIVE ANALYSIS OF GENE SPECIFIC ONCOTYPE DX ASSAY IN
PATIENTS WITH BREAST CANCER (TURKISH CASES)
Göker E1, Görümlü G1, Batıgün O2
1 University of Ege – Department of Oncology, 2 TEVA Turkey
RATIONALE: Breast cancer is the second most prevalent type
following lung cancer in females. 1 Out every 8 women is vulnerable to
breast cancer during lifetime. One of the major challenges in such a
highly seen disease is the determination of initial risk factors and
prediction of chemotherapy benefit. Oncotype DX is a gene/patient
specific assay that is recommended by ASCO (American Society of
Clinical Oncology) and NCCN (National Comprehensive Cancer
Network) guidelines.
United States
Turkey
31≤
13%
When we segment the data into subgroups; we see that minority of the
patients are in premenapousal period (17% - under 40 years of age),
the majority of them are between 40 – 50 years of age (55% - n=16)
and the remaining are over 50 (28% n=13). The risk scores of
premenapousal women present a different profile than other age groups
where high risk and low risk patients are equivalent (n=3 in both arms).
Taking into account that the total population in this group is 8, we need
more subjects to reach an analytic conclusion. 55% of our study group
consists of perimenapousal patients (n=26) where only 15% has high
recurrens scores. In other words 15% the women would anticipate
therapeutic benefit from chemotherapy while 62% (n=16) may try
hormonal treatment alternative.
19%
30%
18 - 30
18>
52%
Patients Under 40 n=8
40%
Ages Between 40 - 50 n=26
18>
18 - 30
35%
RESULTS: The Turkish patients who took Oncotype DX assay
presented a milder profile compared to the ones in United States. 60%
Of Turkish subjects were in low risk group where only 19% were found
to be high risk patients. Compared to the data of 85.000 women in
United States, the results will possibly approach to each other as the
number of Turkish assays increase (52% of women in US are
considered as low risk where 13% are classified as high risk). Patients
in peri and post-menapousal period are likely to have similar results
while pre-menapousal women differ. However, it is obvious that the data
will change with the increasing number of patients.
31≤
21%
60%
80%
20%
60%
10%
40%
0%
18>
20%
0%
Risk Score All Patients (n=47)
18>
18 - 30
31≤
28
10
9
60%
21%
19%
METHOD: In Oncotype DX assay, patients are stratified into 3 groups
according to their risk scores: 18> indicates that the patient has a low
risk of recurrence (the patient will certainly benefit much from hormonal
therapy rather than chemotherapy), a risk score of 18 – 30 means that
the recurrence is at intermediate risk, 30< risk score denotes that the
patient is likely to have a recurrence and would benefit much from
chemotherapy. In this paper we have analysed 47 patients from Turkey
who has taken the assay between September 2008 till August 2009.
When we make an age classification we see that 17% of the women
(n=8) are below 40, 55% of the women (n=26) are between 40 – 50
and 28% of them (n=13) are over 50 years of age. All the patients
except one of them are ER positive. The total risk score analysis show
that: 60% of all the women are in low risk group, 21% of them are
intermediate and only 19% of the patients are supposed to benefit from
chemotherapy. This data concludes that 6 out of 10 women expect to
have lower therapeutic effect from chemotherapy.
18>
18 - 30
31≤
Risk Score Under 40 (n=8)
18>
18 - 30
31≤
3
2
3
38%
25%
38%
31≤
Risk Score for Age 40 - 50 (n=26)
18>
18 - 30
31≤
16
6
4
62%
23%
15%
Postmenapousal patients make 28% (n=13) of the study group and their
results are correlated with the ones in perimenapousal group. 69% of the
women (n=9) in low risk group anticipate limited benefit of chemotherapy
where only 15% are in high risk segment. The concomitant parameters of
the subjects are: 46 of them are ER positive (n=47), 41 of them are PR
positive. Another important marker is HER2 (Human epidermal growth
factor receptor 2): 6 assays could not generate data, 5 were neutral and
the remaining 36 were HER2 negative.
18 - 30
Patients Over 50 n=13
80%
60%
40%
20%
0%
Risk Score Over 50 (n=13)
18>
18 - 30
31≤
9
2
2
69%
15%
15%
18>
18 - 30
31≤
CONCLUSION: Our analysis show that every 6 patient out of 10 will
have less benefit from chemotherapy. Considering the social and
economic burden of chemotherapy both for the patient and the
caregiver, Oncotype DX may be an alternative approach.