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Cancer Prevention:
Principles and Clinical Practice
English Text
Cancer Prevention: Part 2
VideoTranscript
Professional Oncology Education
Cancer Prevention: Part 2
Time: 11:32
Therese B. Bevers, M.D.
Professor, Clinical Cancer Prevention
Medical Director, Cancer Prevention Center
The University of Texas, MD Anderson Cancer Center
Hi, I am Dr. Terry Bevers, Professor of Clinical Cancer
Prevention and Medical Director of the Cancer Prevention
Center at the University of Texas MD Anderson Cancer
Center. Today, our talk is about Cancer Prevention: Part II.
Spanish Translation
Prevención del cáncer: Parte 2
Transcripción del video
Educación Oncológica Profesional
Prevención del cáncer: Parte 2
Duración: 11:32
Dra. Therese B. Bevers
Profesora de Prevención Clínica del Cáncer
Directora Médica, Centro de Prevención del Cáncer
Universidad de Texas, MD Anderson Cancer Center
Hola. Soy la Dra. Terry Bevers, Profesora de Prevención
Clínica del Cáncer y Directora Médica del Centro de
Prevención del Cáncer del MD Anderson Cancer Center de
la Universidad de Texas. Hoy nuestra charla será sobre la
Prevención del cáncer: Parte II.
Cancer Prevention: Part II
Therese B. Bevers, M.D.
Professor, Clinical Cancer Prevention
Medical Director, Cancer Prevention Center
1
Cancer Prevention:
Principles and Clinical Practice
Objectives
Upon completion of this lesson, participants will
be able to:
In a previous lecture, you heard Sally Scroggs talk about
lifestyle modifications for risk reduction. Today, the
lecture will focus on understanding types of prophylactic
surgical interventions used to prevent malignancies and
identification of chemoprevention strategies for several
common cancers.
En una conferencia anterior, Sally Scroggs habló sobre las
modificaciones del estilo de vida para reducir el riesgo.
Hoy, la conferencia se centrará en las intervenciones
quirúrgicas profilácticas empleadas para prevenir los
tumores malignos y en la identificación de estrategias de
quimioprevención para los cánceres más comunes.
I want to first focus on prophylactic surgical interventions.
Primero hablaré de las intervenciones quirúrgicas
profilácticas.
• Discuss lifestyle modification strategies for
risk reduction
• List types of prophylactic surgical interventions
used to prevent malignancies
• Identify chemoprevention strategies for several
common cancers
Cancer Prevention:
Principles and Clinical Practice
Risk Reduction Strategies
•
Health Promotion
-
Diet
Lifestyle modification
•
Prophylactic surgical interventions
•
Chemoprevention
2
Cancer Prevention:
Principles and Clinical Practice
Prophylactic Surgical Interventions
•
Surprisingly, there are a number of surgical interventions
that can be used to reduce an individual’s risk of developing
cancer. Today, I would like to focus on prophylactic
mastectomy and prophylactic salpingo-oophorectomy.
Hay varias intervenciones quirúrgicas que se usan para
reducir el riesgo de desarrollar cáncer. Hoy voy a hablar de
la mastectomía y la salpingooforectomía profilácticas.
Prophylactic mastectomy is the removal of the breast
tissue, both sides, to reduce a woman’s risk of developing
breast cancer. This strategy is highly effective for breast
cancer risk reduction; reducing a woman’s chance of
developing the disease by about 90%. However, it does
carry some significant risk associated with it. It alters a
woman’s body form permanently and her own self-image.
It is irreversible. And for these reasons we typically only
consider it in exceptional circumstances.
Such
circumstances would be a woman who is a gene mutation
carrier for a BRCA1 or BRCA2 mutation. The risk is quite
high carrying a 50% to 80% lifetime risk. Given this high
lifetime risk, certainly, we would consider a very highly
effective risk reduction strategy such as prophylactic
mastectomy.
La mastectomía profiláctica es la extirpación del tejido
mamario de ambos lados para reducir el riesgo de una
mujer de desarrollar cáncer de mama. Esta estrategia es
muy eficaz, pues disminuye en un 90% la probabilidad de
que una mujer desarrolle la enfermedad, aunque conlleva
ciertos riesgos considerables: altera en forma permanente la
forma corporal de una mujer y su propia imagen, y es
irreversible. Por estas razones, generalmente sólo la
consideramos en circunstancias excepcionales. Por ejemplo,
si una mujer es portadora de una mutación en los genes
BRCA1 o BRCA2, su riesgo de por vida es bastante alto, de
un 50% a un 80%, por lo que evaluaríamos una estrategia
de reducción de riesgos muy eficaz, como lo es la
mastectomía profiláctica.
Breast Cancer
– Prophylactic mastectomy
– Prophylactic salpingo-oophorectomy
•
Ovarian Cancer
– Prophylactic salpingo-oophorectomy
•
Colorectal Cancer
– Prophylactic colectomy
Cancer Prevention:
Principles and Clinical Practice
Prophylactic Mastectomy
• Highly effective
– 90% risk reduction
• Alters body form and image
• Irreversible
• Need only be considered in exceptional
circumstances
– Genetic predisposition
3
Cancer Prevention:
Principles and Clinical Practice
Prophylactic Oophorectomy
• Risk Reduction
– Breast cancer
47-68%
– Ovarian cancer 85-96%
• Causes premature menopause with systemic effects
• Use of postmenopausal HRT does not appear
to increase breast cancer risk
Cancer Prevention:
Principles and Clinical Practice
Risk Reduction Strategies
•
Another prophylactic surgical intervention is prophylactic
oophorectomy or prophylactic salpingo-oophorectomy
where the tubes and ovaries on both sides are removed.
This not only reduces a woman’s chance of developing
ovarian cancer by about 85 to 96%, but also reduces a
woman’s chance of developing breast cancer if done early
in her 30s or 40s. The breast cancer risk reduction can be
as much as 47% to 68%. There are risks associated with
this particular surgical intervention. It does cause
premature menopause with all the associated systemic
effects, such as increased risk of heart disease, increased
risk of osteoporosis, and associated menopausal symptoms,
such as hot flashes, night sweats, and the like. One study
has shown that the use of postmenopausal hormone therapy
does not appear to affect a woman’s risk of developing
breast cancer if she were to take it after a prophylactic
oophorectomy.
Now, I want to switch our attention to chemoprevention,
which is the use of medications to reduce an individual’s
risk of developing the disease, in this case, cancer.
Otra intervención quirúrgica profiláctica es la ooforectomía
profiláctica o salpingooforectomía profiláctica, donde se
extirpan trompas y ovarios de ambos lados. Esto reduce la
probabilidad de una mujer de desarrollar cáncer de ovario
de un 85% a un 96%, y de que desarrolle cáncer de mama si
se hace en forma anticipada entre los 30 y los 40 años.
La reducción del riesgo de cáncer de mama puede ser del
47% al 68%. Hay riesgos asociados a esta intervención
quirúrgica. Causa menopausia prematura y todos sus
efectos sistémicos asociados, como aumento del riesgo de
enfermedades cardíacas y de osteoporosis, así como
síntomas asociados con la menopausia, como sofocos,
sudores nocturnos, etc. Un estudio ha demostrado que la
terapia hormonal posmenopáusica no parece afectar el
riesgo de una mujer de desarrollar cáncer de mama si se
administra después de una ooforectomía profiláctica.
Ahora hablaremos de la quimioprevención, que es el uso de
medicamentos para reducir el riesgo de un individuo de
desarrollar la enfermedad, en este caso, cáncer.
Health Promotion
-
Diet
Lifestyle modification
•
Prophylactic surgical interventions
•
Chemoprevention
4
Cancer Prevention:
Principles and Clinical Practice
Chemoprevention
The use of medication to reduce the development of
disease mechanisms:
•
Modify estrogen response
(selective estrogen receptor
modulators - SERMs)
•
Interfere with estrogen production
(aromatase inhibitors)
•
Block cyclo-oxygenase (NSAIDs)
•
Alter ovulation
•
Protect cells from oxidative stress
•
Suppress cell proliferation
(difluoromethylornithine - DFMO)
•
Block carcinogens from
binding DNA
•
Retinoids (vitamin A derivatives)
•
Deltanoids (vitamin D derivatives)
Cancer Prevention:
Principles and Clinical Practice
Chemoprevention
•
-
Hablaré brevemente sobre dos agentes, el tamoxifeno y el
raloxifeno, que han demostrado reducir el riesgo de cáncer
de mama.
Tamoxifen
Raloxifene
Finasteride (Proscar®, Propecia®)
Liver Cancer
-
•
I want to briefly talk about two agents, tamoxifen and
raloxifene, that have been shown to reduce the risk of
developing breast cancer.
Prostate Cancer
-
•
Hay muchos medicamentos o sustancias que están siendo
exploradas para reducir el desarrollo del cáncer. Esta es una
lista parcial. Algunos, como los moduladores selectivos de
los receptores de estrógeno, han sido aprobados por la FDA
para reducir el riesgo de desarrollar cáncer de mama. Otros
siguen bajo investigación. Los mecanismos propuestos
están en la diapositiva.
Breast Cancer
-
•
There are a large number of medications or substances that
are being explored to reduce the development of cancer.
This list is just a partial list. Some such as SERMs, or
Selective Estrogen Receptor Modulators, actually have
FDA approval for their use to reduce the risk of developing
breast cancer. Others are still under investigation. The
proposed mechanisms are listed on this slide.
Hepatitis B Vaccine
Cervical Cancer
–
HPV Vaccine
5
Cancer Prevention:
Principles and Clinical Practice
Tamoxifen and Raloxifene
• Both drugs reduce the risk of invasive and non-invasive
breast cancer by 50%
• Both drugs reduce the risk of osteoporotic bone fractures
• Raloxifene has fewer risks than tamoxifen
– Fewer DVT and PE
– No increased risk of:
• Endometrial cancer
• Cataracts
These drugs reduce the risk of both invasive and
noninvasive breast cancer by one-half. They also reduce
the risk of developing osteoporotic-type bone fractures.
There are, however, risks associated with both of these
drugs. Raloxifene has fewer risks than tamoxifen, has
fewer deep vein thromboses or DVTs, and fewer pulmonary
embolus or PEs. It does not have the increased risk of
endometrial cancer or cataracts that is seen with tamoxifen.
The side effects in regards to hot flashes, vaginal dryness,
and other annoying side effects are fairly comparable
between the two drugs.
Estos fármacos reducen a la mitad el riesgo de cáncer de
mama invasivo y no invasivo, así como el de fracturas
óseas de tipo osteoporósico. Hay ciertos riesgos asociados
con ambos. El raloxifeno tiene menos riesgos que el
tamoxifeno, y menos episodios de trombosis venosa
profunda y embolia pulmonar. A diferencia del tamoxifeno,
no aumenta el riesgo de cáncer de endometrio o cataratas.
Los efectos secundarios en cuanto a sofocos, sequedad
vaginal y otras consecuencias molestas son bastante
similares en ambos fármacos.
Women, who are at increased risk, have options now to
reduce the risk of developing breast cancer. Premenopausal
woman have the option of taking tamoxifen.
Postmenopausal woman have the option of either tamoxifen
for five years or raloxifene for lifelong use.
Las mujeres con mayor riesgo de cáncer de mama tienen
ahora alternativas para reducirlo. La mujer premenopáusica
puede tomar tamoxifeno. La mujer posmenopáusica tiene la
opción de tomar tamoxifeno durante cinco años, o
raloxifeno por el resto de su vida.
• Side effects comparable
Cancer Prevention:
Principles and Clinical Practice
Breast Cancer Chemoprevention
Options for women at increased risk of developing
breast cancer:
• Premenopausal
– Tamoxifen
• Postmenopausal
– Tamoxifen
– Raloxifene
6
Cancer Prevention:
Principles and Clinical Practice
Chemoprevention
•
-
This study, called the Prostate Cancer Prevention Trial,
actually showed that there were fewer cases of prostate
cancer in the finasteride arm. In looking at 1000 men
followed over seven years, taking either finasteride or no
finasteride, there were actually 15 fewer cases of prostate
cancer in the finasteride arm when compared to the no
finasteride arm. However, somewhat surprisingly, four
more cases of high-grade cancers were seen. It was this
observation that has led to some reluctance in the use of
finasteride generally for men to reduce the risk of
developing prostate cancer.
Este estudio, llamado “Ensayo de prevención del cáncer de
próstata”, demostró que hubo menos casos de la
enfermedad en el grupo tratado con finasterida. Se evaluó a
1000 pacientes varones durante siete años, y en el grupo
tratado con finasterida hubo 15 casos menos de cáncer de
próstata que en el grupo no tratado con este fármaco.
Sorprendentemente, se observaron cuatro casos más de
cáncer de alto grado. Esta observación generó cierta
reticencia en el uso de finasterida para reducir el riesgo de
cáncer de próstata.
Finasteride (Proscar®, Propecia®)
Liver Cancer
-
•
Tamoxifen
Raloxifene
Prostate Cancer
-
•
Hablemos ahora del cáncer de próstata: un estudio ha
evaluado el Proscar® o finasterida como método preventivo.
Breast Cancer
-
•
Turning our attention now to prostate cancer, we have a
study that has looked at Proscar® or finasteride for the
prevention of prostate cancer.
Hepatitis B Vaccine
Cervical Cancer
–
HPV Vaccine
Cancer Prevention:
Principles and Clinical Practice
Estimated Benefit and Risk from Finasteride on Development of Prostate Cancer
Thompson IM et al. N Engl J Med 2003 349(3):215
7
Cancer Prevention:
Principles and Clinical Practice
Chemoprevention
•
-
I want to briefly talk about hepatitis B and the hepatitis B
vaccine. We know that hepatitis B and hepatitis V --hepatitis B and hepatitis C infections are major risk factors
for the development of hepatocellular or liver carcinoma.
In fact, the risk is even greater if there is infection with both
hepatitis B and C. Chronic infections with these account
for about 40% of cases of hepatocellular or liver cancer that
are seen. It has been hypothesized that vaccination against
hepatitis B may reduce the incidence of liver cancer by as
much as one-half.
Hablemos brevemente sobre la hepatitis B y su vacuna. Las
hepatitis B y C son los principales factores de riesgo del
carcinoma hepatocelular o hepático. De hecho, el riesgo es
mayor si hay infección con ambos tipos de hepatitis. Las
infecciones crónicas de estas enfermedades representan
cerca del 40% de los casos de cáncer hepatocelular o
hepático. Se ha especulado que la vacunación contra la
hepatitis B puede reducir hasta un 50% la incidencia de
cáncer hepático.
Finasteride (Proscar®, Propecia®)
Liver Cancer
-
•
Tamoxifen
Raloxifene
Prostate Cancer
-
•
Veamos ahora algunas vacunas que pueden ser beneficiosas
para reducir el riesgo de cáncer.
Breast Cancer
-
•
Turning our attention now to some vaccines that can be
beneficial in reducing individuals’ risk of developing
cancer.
Hepatitis B Vaccine
Cervical Cancer
–
HPV Vaccine
Cancer Prevention:
Principles and Clinical Practice
Hepatitis B
• Hepatitis B and hepatitis C infections are major
risk factors for hepatocellular carcinoma (HCC)
• Risk is greater with coinfection with both
hepatitis B and C
• Chronic hepatitis B and C infection account for
0-40% of cases of HCC
• Vaccination against hepatitis B may reduce risk
of HCC by 50%
8
Cancer Prevention:
Principles and Clinical Practice
Hepatitis B Vaccine
• Part of childhood immunization series
• High risk adult populations
–
–
–
–
–
–
Have >1 sex partner in 6 months
Men who have sex with other men
Sex contacts of infected people
IV drug users
Healthcare workers
Household contacts of persons
with chronic HBV infection
– Hemodialysis patients
Cancer Prevention:
Principles and Clinical Practice
We have been using hepatitis B vaccine as part of the
childhood immunization series for a number of years.
Certainly, the individuals who routinely received hepatitis
B vaccine are still under the age that we would normally
expect to see liver cancer develop. So it will be a while
before we begin to see the effects of hepatitis B vaccination
on the population. There are, however, some high-risk
adult populations that are listed here, and these populations
should seriously be considered for hepatitis B vaccination
to reduce the risk of being infected with hepatitis B and,
thus, potentially reduce the risk of developing liver cancer.
Desde hace varios años, la vacuna contra la hepatitis B es
parte de la serie de inmunización infantil. Las personas que
habitualmente son vacunadas contra la hepatitis B son más
jóvenes que la edad a la que normalmente se manifiesta el
cáncer hepático. Entonces, aún falta tiempo para que
comencemos a ver los efectos de la vacunación contra la
hepatitis B en la población. En esta lista figuran algunas
poblaciones de adultos de alto riesgo que deben considerar
seriamente la vacuna contra la hepatitis B para reducir el
riesgo de infección y, en consecuencia, reducir
potencialmente el riesgo de cáncer hepático.
Finally, I would like to talk about cervical cancer and HPV
vaccine or human papillomavirus vaccine.
Por último, hablaré del cáncer cervicouterino y de la vacuna
contra el VPH o virus del papiloma humano.
Chemoprevention
•
Breast Cancer
-
•
Prostate Cancer
-
•
Finasteride (Proscar®, Propecia®)
Liver Cancer
-
•
Tamoxifen
Raloxifene
Hepatitis B Vaccine
Cervical Cancer
–
HPV Vaccine
9
Cancer Prevention:
Principles and Clinical Practice
HPV Vaccine
• Quadrivalent HPV vaccine (Gardasil®)
– HPV 6, 11, 16 and 18
• Bivalent HPV vaccine (Cervarix®)
– HPV 16 and 18
• Nearly 100% effective in protecting against
precancerous lesions caused by HPV 16 and 18
– HPV 16 and 18 cause 70% of cervical cancers
• Quadrivalent HPV vaccine (Gardasil®) also protects
against HPV 6 and 11
– Cause over 90% of genital warts
Cancer Prevention:
Principles and Clinical Practice
HPV Vaccine
• Will not protect against HPV infection by other
high risk types, so screening is still needed
• Vaccine does not treat HPV infection only
prevents it
• To be effective, the vaccine should be given
prior to the initiation of sexual activity
There are actually two different types of HPV vaccines that
are now available on the market. Gardasil® is a
quadrivalent vaccine, meaning it has four types of HPV
included in the vaccine. It has two high-risk or oncogenic
cancer causing types, which is HPV 16 and 18, and two
low-risk types HPV 6 and 11. Cervarix® is a bivalent
vaccine focusing only on the high-risk types, HPV 16 and
18. It has been found in studies that women who were
immunized with HPV vaccine obtained nearly 100%
prevention against the development of precancerous lesions
caused by HPV 16 and 18. It is important to realize that
HPV 16 and 18 account for about 70% of the cervical
cancers that occur in the United States. Because Gardasil®
also includes HPV 6 and 11 in the vaccine, it can prevent
against the diseases that those are associated with,
specifically genital warts. In fact, they are the cause of over
90% of genital warts. While these are not oncogenic or
cancer-causing, certainly they can be problematic, and there
is the potential to reduce the incidence of these developing.
HPV vaccine will not protect against HPV infection caused
by other high-risk types, so we still continue to need --- we
still need to screen women with the Pap smear because
certainly they can have an HPV infection from other highrisk types that would lead to cervical dysplasia or cervical
cancer. The vaccine does not treat an HPV infection. In
fact, there is no treatment currently for HPV infections. It
only prevents the infection from occurring. For that reason,
to be most effective, the vaccine should be given prior to
the initiation of sexual activity, as HPV is largely
transmitted through sexual activity.
Hay en el mercado dos tipos de vacunas contra el VPH.
Gardasil® es una vacuna tetravalente, pues incluye cuatro
tipos de VPH. Dos de ellos son oncogénicos y causan
cáncer de alto riesgo: VPH 16 y 18. Los otros son de bajo
riesgo: VPH 6 y 11. Cervarix® es una vacuna bivalente que
sólo previene dos tipos de alto riesgo. Varios estudios han
comprobado que las mujeres inmunizadas con la vacuna
contra el VPH obtuvieron casi un 100% de prevención en el
desarrollo de lesiones precancerosas causadas por el VPH
16 y 18. Es importante advertir que, en los Estados Unidos,
estos virus representan alrededor del 70% de los cánceres
cervicouterinos. El Gardasil® también incluye el VPH 6 y el
11, por lo que puede, además, prevenir las enfermedades
asociadas a ellos que causan más del 90% de las verrugas
genitales. Si bien no son oncogénicos ni provocan cáncer,
pueden ser problemáticos y existe el potencial de reducir la
incidencia de esta enfermedad.
La vacuna contra el VPH no protege contra las infecciones
de otros tipos de alto riesgo, por lo que aún debemos
utilizar el examen de Papanicolaou. Una infección por VPH
de otros tipos de alto riesgo puede resultar en displasia
cervical o cáncer cervicouterino. La vacuna no cura una
infección por VPH —de hecho, no hay un tratamiento para
estas infecciones—, sino que evita que la infección se
produzca. Por esa razón, para ser más eficaz, la vacuna
debe aplicarse antes de iniciar la actividad sexual, ya que el
VPH se transmite mayormente de ese modo.
10
Cancer Prevention:
Principles and Clinical Practice
CDC Recommendations: HPV Vaccination
• Routine vaccination of females aged 11-12
• Catch-up vaccination of females aged 13-26
– Counseling regarding diminished benefits of
vaccination after HPV exposure should be provided
• HPV vaccination is not currently recommended for
women aged < 9 or > 26
• New recommendation for quadrivalent HPV vaccine
(Gardasil®) vaccination in males to prevent genital warts
– May decrease transmission of HPV infection
CDC=Centers for Disease Control and Prevention
Cancer Prevention:
Principles and Clinical Practice
Conclusions
• Many primary prevention strategies are available
to reduce the risk of developing cancer to include
lifestyle modifications such as diet, exercise and
avoidance of smoking and excessive sun exposure
• For those at increased risk for the disease,
prophylactic surgery and chemoprevention
may be beneficial as well
The current Centers for Disease Control recommendations
for HPV vaccination are that females aged 11 to 12 should
receive routine vaccination with a series of three
vaccinations over a six-month interval. Females aged 13
through 26 may obtain vaccination as a catch-up
mechanism, but they should also be counseled that, if they
have become sexually active, they may have already been
infected with one of the HPV types in the vaccine, and
would not, thus, obtain protection against that particular
HPV type. For that reason, they may have diminished
benefits from the vaccination. HPV vaccination is not
currently recommended for women under the age of 9 or
over the age of 26, although studies are currently ongoing.
Recently, there have been some new recommendations for
Gardasil® vaccination in males to prevent the development
and transmission of genital warts. Certainly, since
Gardasil® vaccination would also prevent HPV infection
with 16 and 18 in the males, it may help to decrease the
transmission of these two HPV types to their sexual
partners, thus potentially reducing the risk further for the
population.
In conclusion, there are many primary prevention strategies
that are available to reduce a person’s risk of developing
cancer. These include lifestyle modifications, that you
heard Sally talk about, such as diet and exercise, avoidance
of smoking, or smoking cessation if you already smoke, and
excessive sun exposure. Also for those who are at
increased risk of the disease, we have other options, such as
prophylactic surgical interventions and chemoprevention. I
hope that you have enjoyed this lecture and we welcome
your feedback. Thank you.
Los Centros para el Control y la Prevención de
Enfermedades recomiendan la vacunación de rutina contra
el VPH en mujeres de 11 a 12 años, con una serie de tres
aplicaciones a intervalos de seis meses. Las mujeres de 13 a
26 años pueden vacunarse como un mecanismo de
protección, pero se les debe advertir que si han llevado una
vida sexual activa, es posible que ya hayan sido infectadas
por uno de los tipos de VPH contenidos en las vacunas y
que, por lo tanto, no obtendrán protección. Es posible
entonces que obtengan menos beneficios. La vacuna contra
el VPH no se recomienda para mujeres menores de 9 años o
mayores de 26, aunque aún se están realizando estudios.
Las recomendaciones más recientes indican la vacunación
con Gardasil® en los hombres a fin de prevenir el desarrollo
y la transmisión de verrugas genitales. Ya que Gardasil®
también previene la infección con VPH 16 y 18 en los
varones, puede reducir la transmisión de estos virus a sus
parejas sexuales, lo cual reduciría aún más el riesgo para la
población.
En conclusión, hay muchas estrategias de prevención
primaria para reducir el riesgo de desarrollar cáncer, que
incluyen modificaciones en el estilo de vida —de las que
Sally ha hablado—, como dieta y ejercicio, no fumar o
dejar de fumar si ya se hace, y evitar la exposición excesiva
al sol. Para aquellos con mayor riesgo de desarrollar la
enfermedad, tenemos otras opciones, como intervenciones
quirúrgicas profilácticas y quimioprevención. Espero que
hayan disfrutado de esta conferencia y agradeceremos sus
comentarios. Gracias.
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