Predictive AI Models for the Personalized Medicine
Luigi Lella
1
, Ignazio Licata
2
, Gianfranco Minati
3
, Christian Pristipino
4
, Antonio Giulio De Belvis
5
and Roberta Pastorino
5
1
ASUR, Regional Health Agency of Marche, AN, Italy
2
ISEM, Inst. for Scientific Methodology, PA, Italy
3
AIRS, Italian Association for Systems Research, MI, Italy
4
ASSIMSS, Italian Association for Systems Medicine & Healthcare, Rome, Italy
5
Section of Hygiene, Inst. of Public Health, Università Cattolica del Sacro Cuore, Rome, Italy
Keywords: e-Health, e-Health Applications, Pattern Recognition and Machine Learning, Decision Support Systems.
Abstract: Innovative information systems which enable personalized medicine are presented. The designed decision
support systems are expected to infer with an excellent level of accuracy the outcome of a therapeutic
intervention through the analysis of biometric, genetic and environmental data. They are also capable to
motivate their predictions according to a dynamic knowledge base, which is kept updated with new
analysed cases. These systems can be used by researchers to identify useful correlations between biometric,
genetic and environmental data with potential risks and benefits of certain therapeutic choices. They can
also be used by the patients to choose the most appropriate therapeutic intervention according to their needs
and expectations. In other words the presented decision support tools can realize the vision of the predictive,
preventive, personalized and participatory (P4) medicine pursued by the systemic medicine.
1 INTRODUCTION
As reported in (Personalized Medicine, 2013),
personalized medicine has opened a new rapidly
growing market in the European industry, also
creating new job opportunities.
The purpose of personalized medicine is
essentially to contain healthcare expenditure at a
time when the cost of healthcare delivery is growing
throughout Europe along with the prevalence of
chronic diseases and disorders, and more than 6% of
readmission cases hospital due to acute conditions
are caused by serious adverse drug reactions.
Research on the correlations between biological
mechanisms, environmental interactions and the
development or evolution of certain diseases and
disorders will have a significant impact throughout
the health care chain, from the research world to the
provision of health care services (Saqui M. et al.
2016).
Despite the development of some personalized
medicine approaches, we are still in one of the first
stages of implementation of this intervention
strategy (Nimmersgern E., 2017). According to a
recent review of the personalized medicine literature
presented by (Di Paolo A. et al. 2017), focused on
research carried out within the European Union,
there would not seem to be even sufficient
consensus on the definition and conception of
personalized medicine itself.
Some articles correlate its definition to the
concept of stratification or subdivision of patients
into subgroups, depending on the probability of
receiving benefits from the adoption of a specific
pharmaceutical therapy or clinical treatment. Others
instead frame it as the assignment of a tailored
therapy to patients on the basis of new individual
and dynamical classifications of diseases based on
their molecular basis and networking characteristics
rather than only on clinical grounds.
As pointed out by the authors, the initial state of
the patients is almost always evaluated considering
mainly their genetic data and their biological
markers together with the outcome of some
specialized examinations. Instead, other factors such
as the clinical evolution over time, as well as the
needs and preferences of the patient should be
considered as also required by a recent European
recommendation (Personalised Medicine 2010)
(Sagner M. et al 2017). Also according to (Di Paolo
396
Lella, L., Licata, I., Minati, G., Pristipino, C., De Belvis, A. and Pastorino, R.
Predictive AI Models for the Personalized Medicine.
DOI: 10.5220/0007472203960401
In Proceedings of the 12th International Joint Conference on Biomedical Engineering Systems and Technologies (BIOSTEC 2019), pages 396-401
ISBN: 978-989-758-353-7
Copyright
c
2019 by SCITEPRESS Science and Technology Publications, Lda. All rights reserved
A. et al. 2017), further research work is aimed both
at predicting the individual outcomes of certain
treatments and the probability of incurring collateral
effects (Baumbach J. et al. 2018).
Regarding the technologies used in these deep
learning tasks, literature seems to converge in recent
years on the use of recurrent neural networks, in
particular those models based on the Long Short-
Term Memory (LSTM) paradigm for the analysis of
genetic data (Vohradsky J. 2009; Xu R. et al. 2007)
or the analysis of data contained in electronic
medical records (Lipton Z.C. et al. 2017; Pham T. et
al.2017).
This paper presents some solutions based on
machine learning systems able to infer the outcome
of a given treatment together with any side effects
on the basis of patients status (genetic data,
biometric data, environmental data), the chosen
therapies, their needs and preferences.
In agreement with (Di Paolo A. et al. 2017) we
believe that just by the adoption of a holistic
approach, that does not consider only genetic data
and biological markers but also the environment and
the needs of the patients, it is possible to effectively
deal with the problem of personalized medicine,
adapting it exactly to the profile of patient. Through
the development of outcome measures co-developed
between researchers, patients and subject experts we
will cover what really matters to patients, embracing
the cognitive, self-cognitive, psychological,
symbolic, social, ecological and environmental
dimensions.
Most machine learning techniques are oriented
towards a kind of structural representation of
knowledge. This can be symbolic or subsymbolic.
Sub-symbolic models can achieve the best results in
problems that are difficult to solve if a static
knowledge base consisting of simple logical
production rules is adopted. Sub-symbolic models
can be further subdivided into classification learning
algorithms (Kohonen T., 1988; Rumelhart D.E. and
McClelland J. L., 1986), association learning
algorithms (Kohonen T., 1989) and clustering
learning algorithms (Van Hulle M. M., 2012;
Kohonen T. 1990; Fritzke B., 1994; Licata I. and
Lella L., 2007).
In classification learning, the system is trained to
provide a given output (a class) from a set of
classified examples. This type of model, to which
LSTMs belong, is only effective if the correlations
between non-class attributes and all the possible
classes are known in advance. This model does not
therefore adapt to the case of the predictions of
therapeutic choices in personalized medicine, since
it can be very complicated to define the rules of
association between individual profiles of patients
and possible therapeutic interventions.
In association learning there are no specific
classes, the system only tries to find an interesting
scheme or a correlation between the data.
Association rules can be used to predict attributes of
any kind, not just class ones. Since we are interested
in predicting the therapeutic choice, the duration of
therapy, the risks and the results that can be
achieved, association learning models are not suited
to solve the problem.
Finally clustering algorithms are unsupervised,
meaning that there is no set of classified examples
that can be used to train the system. If we choose the
duration of therapy, the achievable results and
possible side effects as class attributes, the system
can extrapolate several clusters related to class
attributes. In this way it is possible to avoid the
presence of human experts making this solution
more interesting and easy to implement.
Among the algorithms belonging to this last
family the SOM (Kohonen T., 1989) have been
widely used in healthcare, but we believe that the
best results can be obtained using more adaptive
models. In this type of unsupervised learning
activity there is no clear correlation between class
attributes and the other ones. In other words, the
exact topology of the input space is unknown.
B. Fritzke in one of his articles showed that his
network model called GNG (Fritzke B., 1994) is
able to identify exactly the local dimension of the
input space, i.e. a GNG can find how many
attributes in the defined input space are needed to
accurately predict the considered class attributes.
As a further model to be compared with the self-
organizing neural networks and the LSTMs, we will
test the self-organizing symbolic model of the Non
Organized Turing Machine (A-Type) (Turing A.,
1948) consisting essentially of a network of NAND
gates by which it is possible to construct a sort of
knowledge base modelling the problem. This
network will evolve through the use of various
algorithms that encode the network configuration by
means of fixed-length bit sequences. In particular we
will consider Genetic Algorithms (Eiben A. E. and
Smith J. E., 2015; Mitchell A.E., 2015) and Swarm
Intelligence algorithms (Praveena S., 2018).
A Non-Organized Turing Machine is a symbolic
model from which we expect a lower performance in
terms of prediction accuracy than the considered
subsymbolical models, but an A-type may be able to
justify the inferred answers by resorting to a
dynamic logical formalism.
Predictive AI Models for the Personalized Medicine
397
The trained machine learning models will allow
professionals and assistants to select the most
suitable therapeutic regimen to treat the clinical case
taken care of. The patient will have the opportunity
to evaluate the outcome of a pharmacological or
specialist therapy by selecting it from the list of
those already used to treat similar cases.
This will lead not only to the patient's
empowerment, but it will also lead to the realization
of the long-awaited therapeutic alliance between
caregiver and doctor who has taken care of him,
limiting inappropriate interventions.
To achieve this result it is important to define
diseases more precisely and to stratify patients into
subgroups, based on their likelihood of responding
to a given treatment, and also to stratify healthy
citizens according to their risk of disease.
The classic approach of diagnosis and treatment
must be overcome through specific omics data
acquisition, the individual profile of the subject is
assessed, enabling the choice of a specific
therapeutic strategy. It is thus possible to minimize
the "toxic cost" of the therapy, improving the
patient's quality of life and optimizing the
management of the available economic resources.
The described models will be tested at the the
University Polyclinic Foundation Agostino Gemelli
Hospital Center with the help of ad hoc resources
collecting information which is not already collected
routinarily. The expected pathology specific clinical,
economic, quality and humanistic outcomes will be
suggested by the involved multidisciplinary team.
2 METHODS
As input data to encode patients status, a binary
vector will be assembled that encodes the genetic
information, the molecular fingerprints (e.g. -omics),
the biometric information, the clinical data, the
therapeutic choice, the exposome, and the needs and
the psychological dimensions of the patient and of
his/her social networks.
As far as genetic information is concerned, a
selection could be made, at least during the test
phase of the developed decision support system, of
all the possible about 30,000 human genes,
considering only those that research considers useful
for predicting the onset of disorders or diseases. For
cancer alone, for example, large-scale studies (Hill
S., 2018) have confirmed that there are about 450
"key genes" to be considered in the prediction of the
onset or evolution of different forms of cancer.
In order to reduce the training and processing
times of the chosen machine learning models, the
considered cases could be limited only to a set of
tumor forms that are particularly incident on the
territory.
The encoding of such data will be accompanied
by the codification of the outcome of some related
specialist examinations. For example, the key gene
for breast cancer called HER2 (Perez E.A. et al.,
2014) is associated with the IHC (Immuno Histo
Chemistry) exam that identifies the percentage of
HER2 proteins in tumor cells, and with FISH
(Fluorescence In Situ Hybridization), SPoT-Light
HER2 CISH test and Inform HER2 Dual ISH test to
identify if there are too many pairs of HER2 genes
in tumor cells. The outcome of all these specialized
examinations must be appropriately coded using a
simple binary coding in the case of results that can
be simply positive or negative or a "one-hot" coding,
having as many bits as all the possible outcomes,
and with only one of these coded as 1. For the IHC
test of the HER2 gene, for example, the code "1000"
can be used for the "negative" result, the code
"0100" for the result "also negative", the code
"0010" for the result "borderline" and the code
"0001" for the "positive" result. A one-hot code
should also be used to codify the choice of treatment
regimen, the status and the needs of the patient.
The indicators to be taken into consideration to
define the patient's status and needs will be taken
from the information systems for the measurement
of the outcomes reported by the patients as the one
developed within the PROMIS project (Cella D. et
al., 2010) or other outcome measures reported from
the patients studied in literature (Black N., 2013)
(Donabedian A., 1988). The outcome measures
reported by the patients (PROM) are measures of
functionality and well-being in the sphere of the
patient's physical, mental and social health (Black
N., 2013).
To codify the output of the chosen forecasting
models, a vector with the one-hot coding of the
duration of the therapy will be assembled (duration
divided into classes or periods, for example: 0-6
months, 6-12 months> 1 year), together with a one-
hot vector with the possible pathology specific
outcomes (also in this case we will adopt the
PROMIS coding system), and a sequence of binary
codes (present or not present) associated with
possible side effects.
To improve the learning process of the chosen
self-organizing networks (SOM and GNG) as well
as the Non-Organized Turing Machine, we will
adopt the methodology suggested by Kohonen
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(Kohonen T., 1990). The input vector of the chosen
models will be constructed by concatenating a
contextual part that represents the class attributes of
the instance and a symbolic part composed of the
other attributes. The part of the symbol and the part
of the context will therefore be represented by two
orthogonal vectors such that the norm of the second
is larger than that of the first. In this way, in the
subsimbolic prediction models taken into account
the symbols can be coded in a topological order
(connection between neural units) that reflects the
logical analogies.
The implemented evolutionary algorithms
(genetic and swarm intelligence) will instead be able
to make more accurate predictions by selecting them
from the considered space of the solutions.
The data set will be divided into a part equal to
the 66% of the samples used as a training set, and a
part equal to the remaining 34% of the samples used
as a test set to evaluate the predictive accuracy of the
model. All of these models have already been
successfully tested in computationally similar
contexts like the length of hospital stay prediction on
the basis of the data contained in the patients
admission forms (Lella L. and Licata I.,2017; Lella
L. and Licata I., 2018).
Finally, it has to be noticed that these models
must be trained with a large number of data, or
rather, following the definition of big data provided
by (Anderson C., 2008; Mayer-Schonberger V. and
Cukier K., 2017; Godsey B., 2018), automatically
collecting, storing and analysing all the clinical data,
managing them as soon as they become available.
As expressed by (Naimi A.I. and Westreich D. J.,
2014) we will not consider the automatic analysis of
all the data as the best adoptable scientific approach.
According to the book review, we believe that all the
available data will never be completely free of bias
and in any case it will be necessary to adopt
preprocessing techniques including resampling.
Instead, it will be fundamental to monitor in real
time all the patients available data in order to follow
the evolution of their clinical picture, suggesting
possible prevention and treatment pathways.
In a future in which the personal, health-related
and environmental information of each individual
will be contained within a "personal data cloud" it
will be possible to analyse in real time all this
amount of data in order to provide people with
useful coaching suggestions on how to improve their
health preventing chronic disorders.
It will be possible, for example, to suggest to an
individual, who has a genetic variant associated with
a high predisposition to type 2 diabetes and a rapid
increase in blood glucose level, to undergo a series
of tests and to adopt certain dietary regimens and
levels of physical activity to avoid the devastating
effects of this disorder.
By activating the participatory component of
medicine, patients will be more involved by making
them aware of the possible consequences of their
behaviour. This will reduce the onset of chronic
disorders through self-monitoring and self-
assessment leading to improved quality of life for
patients and their caregivers.
3 CONCLUSIONS
Data mining and knowledge discovery processes do
not follow precise rules. There is no model or
method capable of producing useful results in any
context of use.
In the case of the prediction of the duration of the
therapy, of the outcome and the side effects of a
personalized medicine case, it may be useful to use
models such as GNG that perform the so-called
dimensionality reduction. These models can find a
sub dimensional space that contains most of all input
data. The GNG model has the potential to adapt
effectively to the input space, but it must be trained
through the use of appropriate preprocessing
techniques. We believe that the GNG model will
perform better than other considered self-organizing
networks, achieving a greater prediction accuracy.
We will also test a second symbolic model that
implements the Non-Organized Turing Machines
that is able to justify its predictions and to
autonomously evolve its knowledge base over time.
The development of these systems is perfectly in
line with two of the objectives specified in the
European Union report on personalized medicine
(Personalized Medicine, 2013), which are primarily
to reduce the number of unnecessary interventions
and adverse events by maximizing the added value
perceived by patients, but also to favour a
containment of welfare costs.
The use of artificial intelligence models in
forecasting the outcomes of therapeutic choices can
contribute to implement the predictive, preventive,
personalized and participatory (P4) vision predicted
and desired by some pioneers of systems medicine
(Flores M. et al. 2013; Auffray C. et al. 2017).
Decision support systems supported by AI
models, such as those presented in this work, will
also make it possible to improve the effectiveness of
medical decisions by moving from symptom-
focused medicine to medicine focused on causes,
Predictive AI Models for the Personalized Medicine
399
highlighting the therapies with the highest
probability of success with the lower level of risk for
each individual wherein the participation of the
patient remains pivotal (Leyens L. et al. 2014).
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