Previous papers highlighted the great variability in terms of percentage of BRCA alteration in series of OC patients reported by different Authors. de-Jong [9] reported an overall probability of presence of germline BRCA1/2 mutations above 10% in 6218 women with epithelial OC confirming three referral criteria to candidate OC women to genetic counseling: age of onset, family history of BC and/or OC and histology. However, he also stressed that categories not fulfilling these selection criteria still have a substantial probability of carrying a germline BRCA mutation concluding that “testing should be offered regardless of those characteristics otherwise an important part of germline BRCA1/2 mutation carriers could be missed” [9]. This position was supported by several authors [8]. Furthermore, the recent updated 3.2019 NCCN guidelines do no longer consider the possibility to utilize genetic risk models (like BRCAPRO) for a better selection of candidates to BRCA test (https://www.nccn.org/professionals/physician_gls/pdf/genetics_screening.pdf).
In the present series we showed by univariate and multivariate analyses that BRCA mutation rate is strongly associated with epithelial histology, low citohistological tumour differentiation and, first of all, with OC or BC family history in first degree relatives (Tables 2 and 3). Several Authors confirmed that the epithelial cancer histology is associated to BRCA mutations. Indeed, Alsop [20] reported a germline BRCA1/2 mutation in 14% of 1001 women with non-mucinous epithelial ovarian cancer (EOC); Zhong [21] pointed out the presence of 17% of BRCA mutations by reviewing a series of 9588 epithelial EOC. In our series of patients, we demonstrated 10.7% percentage of BRCA mutation in epithelial origin OC women; however, as already reported [17], gene deletions and duplications in this series were not analyzed, even if, Kwong [22] demonstrated that large deletions or duplications in BRCA1/2 genes, accounts for 0.7% of all BRCA pathogenic alterations, only.
The most intriguing results of the present paper, came from regression tree analysis which showed that there are subgroups of patients, characterized by a combination of clinical-pathological factors and an enormous difference in BRCA mutation frequencies. For first our original analysis confirms the strong impact that OC and/or BC family history has in determining the probability to carry a BRCA mutation and this, irrespective to age for OC.
We further demonstrated that there is a subgroup of about 20% of all OC patients (without family history, early disease stage, well differentiated) with < 1% of BRCA mutation rate; moreover, a subgroup of 46% of patients, included in Nodes 3 and 5 of the Regression-Tree (Fig. 1) showed a < 3.8% probability only to carry a BRCA mutation. Conversely, this probability resulted particularly high (> 40%) in young women with BCFh (Node 6) or with OCFh (> 29%) (Node8). This is the first time that the concept of hierarchy and of multifactor risk is associated to BRCA mutation rate in a large series of OC women. In fact, our hierarchical approach permitted to individualize patients belonging to Nodes 1–3-5 of the Tree, representing a subset of 66% of all OC patients, with particularly low risk to carry a BRCA mutation vs a subgroup of OC women, representing the 24% of all the series, with a probability to carry a pathogenic mutation always over 17%.
The main conclusion from these data is that the probability to find a BRCA mutation varies greatly in different clinical subgroups leading to the hypothesis that testing for BRCA mutations in OC patients could be better addressed within each specific clinical scenario and according to better defined cost-effective programs.
The question of how to manage, in a cost-effective way, BRCA tests for OC patients has generated a wide debate. D’Andrea [23], after a systematic review on economic evaluations on BRCA genetic testing programs, concluded that there is no evidence of cost-effectiveness for BRCA screening to all newly diagnosed cases of OC cancer even though followed by cascade testing of relatives. Kwon [24], estimating the cost-effectiveness of BRCA mutation testing in USA and the down stream benefits for first degree relatives, confirmed that the benefit concerned only OC women, with a personal history of breast and/or OC. Slade [25] stressed the need for adherence to NICE elegibility criteria requiring a BRCAPRO risk> 10% to reach a useful cost-effectiveness ratio. Eccleston [26], in a study conducted in UK, reached different conclusions reporting that implementing routine BRCA testing in women with OC would be cost-effective but only if compared with no testing to all patients policy.
We can therefore affirm that there is no evidence of a clear cost-efficacy benefit for widespread genetic test to all OC patients when compared to testing selected subgroups of patients only. On the other hand, we have to stress that there is no demonstration that our regression tree model can represent an alternative more cost-effective approach with respect to standard practice. A study to directly compare the performances of our innovative approach with respect to BRCAPRO is ongoing.
However, there is general agreement about the fact that new technological approach (i.e. massive sequencing) will dramatically lower costs and then the cost-efficacy equilibrium for wide BRCA test utilization policies [22,23,24].
An important point supporting the implementation of widespread testing strategies has been the utilization of such test as predictive biomarker for PARP-I stated from FDA and EMA, and, more in general, for an optimal therapeutic strategy design for OC women [8, 27]. In particular, PARP-I utilized in OC women carrying a BRCA mutation as maintenance therapy, has proven to dramatically improve the outcome of these patients [28].
However, regarding these points, alternative views have to be discussed. In 2017, the FDA (www.accessdata.fda.gov) approved two PARP inhibitors, olaparib and niraparib, as maintenance treatment for women with OC who respond to induction platinum-based chemotherapy, regardless of their BRCA-mutation status [28, 29]; recent findings from the phase III ARIEL3 trial of rucaparib corroborate the genotype agnostic benefit of PARP inhibition [30]. Moreover, Tan [31] supported the idea that the delivery of BRCA test as predictive to response to other common drugs (platinum derivatives, trabectedin) utilized for OC patients has to be still considered as an experimental approach. It seems we can conclude that, to date, to know the BRCA test to consider PARP-I utilization and for a better planning a complete therapeutic strategy for OC patients, cannot be simply supported.
Interestingly, the ARIELIII trial scientists stressed the urgent need to a deeper study of homologous recombination repair deficiency (HRD) in patients candidate to PARP-I treatment, also considering the potential harmful effect of false negative BRCA results leading to false patient’s reassurance and to appropriate care neglection [30].
