Objective: Fertility preservation is a priority in oncology for female cancer patients. However, there is a lack of communication between infertility specialists and oncologists. This study aimed to evaluate infertility specialists’ perceptions and experiences regarding fertility preservation. Methods: Conduct an online survey to profile infertility specialists. Participants were infertility affiliated with the Brazilian Federation of Gynecology and Obstetrics Associations (FEBRASGO). The specialists received an online survey, which response rate were 30.9%, most of whom were in southern and southeastern. The survey consisted on 14 questions about the infertility specialists’ location, techniques in clinical practice, treatment successful rate, patients idea, etc. Results: The average experience in human reproduction were 15.5 ± 10.2 years (mean ± standard deviation, range 1-40). Among reproductive-aged female cancer patients recommended for fertility preservation, 60.3 ± 28.8% (range 10-100%) underwent preservation procedures. Main barriers were cost (41%), oncologists’ knowledge or acceptance (35%) and accessibility (9%). Most infertility specialists (58%) considered 40 years the limit for fertility preservation. Leukemia, lymphoma, breast and ovarian cancers were prioritized for fertility preservation, while lung, thyroid, gastric, and brain cancers were less relevant. Conclusion: This is the first Brazilian study about infertility specialists’ perceptions on oncology patients access to fertility preservation. These patients primarily receive treatment in the public health system, while infertility specialists mainly work in the private healthcare. This healthcare mode is currently fragmented, but integrating these experts is enhancing patient access to fertility preservation. Studies on this topic are still warranted. Objective However oncologists Methods FEBRASGO. FEBRASGO . (FEBRASGO) 309 30 9 30.9% southeastern 1 location practice idea etc Results 155 15 5 15. 102 10 2 10. mean deviation 140. 140 1-40) reproductiveaged reproductive aged 603 60 3 60. 288 28 8 28.8 10100% 10100 100% 100 10-100% procedures 41%, 41 41% , (41%) 35% 35 (35% 9%. 9% (9%) 58% 58 (58% 4 Leukemia lymphoma lung thyroid gastric relevant Conclusion system fragmented warranted (FEBRASGO 30.9 1-40 6 28. 1010 10-100 (41% (35 (9% (58 30. 1-4 101 10-10 (41 (3 (9 (5 1- 10-1 (4 ( 10-

Abstract Effective patient positioning is a critical factor influencing surgical outcomes, mainly in minimally invasive gynecologic surgery (MIGS) where precise positioning facilitates optimal access to the surgical field. This paper provides a comprehensive exploration of the significance of strategic patient placement in MIGS, emphasizing its role in preventing intraoperative injuries and enhancing overall surgical success. The manuscript addresses potential complications arising from suboptimal positioning and highlights the essential key points for appropriate patient positioning during MIGS, encompassing what the surgical team should or shouldn't do. In this perspective, the risk factors associated with nerve injuries, sliding, compartment syndrome, and pressure ulcers are outlined to guide clinical practice. Overall, this paper underscores the critical role of precise patient positioning in achieving successful MIGS procedures and highlights key principles for the gynecological team to ensure optimal patient outcomes. outcomes (MIGS field success shouldnt shouldn t do perspective sliding syndrome practice Overall

Abstract Objective To conduct a systematic review of external validation studies on the use of different Artificial Intelligence algorithms in breast cancer screening with mammography. Data source Our systematic review was conducted and reported following the PRISMA statement, using the PubMed, EMBASE, and Cochrane databases with the search terms “Artificial Intelligence,” “Mammography,” and their respective MeSH terms. We filtered publications from the past ten years (2014 – 2024) and in English. Study selection A total of 1,878 articles were found in the databases used in the research. After removing duplicates (373) and excluding those that did not address our PICO question (1,475), 30 studies were included in this work. Data collection The data from the studies were collected independently by five authors, and it was subsequently synthesized based on sample data, location, year, and their main results in terms of AUC, sensitivity, and specificity. Data synthesis It was demonstrated that the Area Under the ROC Curve (AUC) and sensitivity were similar to those of radiologists when using independent Artificial Intelligence. When used in conjunction with radiologists, statistically higher accuracy in mammogram evaluation was reported compared to the assessment by radiologists alone. Conclusion AI algorithms have emerged as a means to complement and enhance the performance and accuracy of radiologists. They also assist less experienced professionals in detecting possible lesions. Furthermore, this tool can be used to complement and improve the analyses conducted by medical professionals. mammography statement PubMed EMBASE Intelligence, Mammography, Mammography “Mammography, 2014 (201 2024 English 1878 1 878 1,87 research 373 (373 1,475, 1475 1,475 , 475 (1,475) 3 work authors location year AUC specificity (AUC alone lesions Furthermore “Mammography 201 (20 202 187 87 1,8 37 (37 147 1,47 47 (1,475 20 (2 18 8 1, (3 14 1,4 4 (1,47 2 ( (1,4 (1, (1

Resumo Objetivo Comparar os padrões de resposta inflamatória sistêmica em mulheres com câncer epitelial de ovário (CEO) ou sem evidência de doença maligna, bem como avaliar o perfil de respostas inflamatórias sistêmicas em tumores dos tipos 1 e 2. Esta é uma forma não invasiva e indireta de avaliar tanto a atividade tumoral quanto o papel do padrão inflamatório durante as respostas pró- e antitumorais. Métodos Ao todo, 56 pacientes foram avaliados prospectivamente: 30 mulheres sem evidência de doença maligna e 26 mulheres com CEO. A quantificação plasmática de citocinas, quimiocinas e micropartículas (MPs) foi realizada por citometria de fluxo. Resultados Os níveis plasmáticos das citocinas pró-inflamatórias interleucina-12 (IL12), interleucina-6 (IL-6), fator de necrose tumoral alfa (tumor necrosis factor alpha, TNF-α, em inglês), interleucina-1 beta (IL-1β), e interleucina-10 (IL-10), e da quimiocina de motivo C-X-C 9 (CXCL-9) e da quimiocina de motivo C-X-C 10 (CXCL-10) foram significativamente maiores em pacientes com EOC do que nos controles. Os níveis plasmáticos da citocina interleucina-17A (IL17A) e MPs derivados de células endoteliais foram menores em pacientes com CEO do que no grupo de controle. A frequência de leucócitos e de MPs derivadas de células endoteliais foi maior nos tumores de tipo 2 do que naqueles sem malignidade. Observou-se um número expressivo de citocinas e quimiocinas inflamatórias/regulatórias nos casos de CEO, além de correlações negativas e positivas entre elas, o que leva a uma maior complexidade dessas redes. Conclusão Este estudo mostrou que, por meio da construção de redes compostas por citocinas, quimiocinas e MPs, há maior resposta inflamatória sistêmica em pacientes com CEO e correlação mais complexa desses biomarcadores em tumores de tipo 2. (CEO pró antitumorais todo 5 prospectivamente 3 (MPs fluxo próinflamatórias interleucina12 interleucina 12 IL12, IL12 IL , (IL12) interleucina6 6 interleucina- IL6, IL6 (IL-6) tumor alpha TNFα, TNFα TNF α, α TNF-α inglês, inglês inglês) interleucina1 IL1β, IL1β ILβ 1β β (IL-1β) interleucina10 IL10, IL10 (IL-10) CXC C X CXCL9 CXCL (CXCL-9 CXCL10 (CXCL-10 controles interleucina17A interleucinaA 17A IL17A ILA (IL17A controle malignidade Observouse Observou se inflamatóriasregulatórias regulatórias elas IL1 (IL12 (IL-6 (IL-1β (IL-10 (CXCL- CXCL1 (CXCL-1 (IL1 (IL- (IL-1 (CXCL (IL

Abstract Objective To compare the patterns of systemic inflammatory response in women with epithelial ovarian cancer (EOC) or no evidence of malignant disease, as well as to evaluate the profile of systemic inflammatory responses in type-1 and type-2 tumors. This is a non-invasive and indirect way to assess both tumor activity and the role of the inflammatory pattern during pro- and antitumor responses. Materials and Methods We performed a prospective evaluation of 56 patients: 30 women without evidence of malignant disease and 26 women with EOC. The plasma quantification of cytokines, chemokines, and microparticles (MPs) was performed using flow cytometry. Results Plasma levels of proinflammatory cytokines interleukin-12 (IL12), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α) interleukin-1 beta (IL-1β), and interleukin-10 (IL-10), and C-X-C motif chemokine ligand 9 (CXCL-9) and C-X-C motif chemokine ligand 10 (CXCL-10) were significantly higher in patients with EOC than in those in the control group. Plasma levels of cytokine interleukin-17A (IL-17A) and MPs derived from endothelial cells were lower in patients with EOC than in the control group. The frequency of leukocytes and MPs derived from endothelial cells was higher in type-2 tumors than in those without malignancy. We observed an expressive number of inflammatory/regulatory cytokines and chemokines in the cases of EOC, as well as negative and positive correlations involving them, which leads to a higher complexity of these networks. Conclusion The present study showed that, through the development of networks consisting of cytokines, chemokines, and MPs, there is a greater systemic inflammatory response in patients with EOC and a more complex correlation of these biomarkers in type-2 tumors. (EOC type1 type 1 type- type2 2 noninvasive non invasive pro 5 3 (MPs cytometry interleukin12 interleukin 12 IL12, IL12 IL , (IL12) interleukin6 6 interleukin- IL6, IL6 (IL-6) TNFα TNF α (TNF-α interleukin1 IL1β, IL1β ILβ 1β β (IL-1β) interleukin10 IL10, IL10 (IL-10) CXC C X CXCL9 CXCL (CXCL-9 CXCL10 (CXCL-10 group interleukin17A interleukinA 17A A IL17A ILA (IL-17A malignancy inflammatoryregulatory regulatory them that IL1 (IL12 (IL-6 (IL-1β (IL-10 (CXCL- CXCL1 (CXCL-1 (IL1 (IL- (IL-1 (CXCL (IL

Resumo Objetivo O presente estudo teve como objetivo desenvolver um modelo matemático útil que prediz a idade na qual a insuficiência ovariana prematura pode ocorrer após a radioterapia externa (teleterapia). O diagnóstico de menopausa prematura ou precoce tem consequências físicas e psicológicas; portanto, as mulheres podem precisar de apoio e acompanhamento médico de longo prazo. Métodos Para correlacionar a dose de radiação ovariana com a função ovariana, foi usada a fórmula descrita por Wallace et al.: √g(z) = 10(2-0,15z), na qual “g(z)” e “z” representam a taxa de sobrevivência do oócito e a dose de radiação (em Gray), respectivamente. Ao simular diferentes idades e doses, observamos um padrão que poderia ser usado para simplificar a relação entre a dose de radiação e o tempo restante da função ovariana. Resultados Obtivemos uma função linear entre a dose de radiação ovariana e a perda da função ovariana (LOF, na sigla em inglês) que é a porcentagem de diminuição no tempo até a falência ovariana em relação ao tempo esperado para uma mulher da mesma idade sem exposição à radiação. Para pacientes<40 anos de idade e com doses de radiação ovariana < 5 Gy, a equação LOF = 2,70 + (11,08 × Dose) pode ser aplicada para estimar a redução no tempo até a insuficiência ovariana. Conclusão O presente estudo relata um método teórico viável para estimar a perda da função ovariana. Estes achados podem melhorar potencialmente o manejo e o aconselhamento de pacientes jovens submetidas à radioterapia durante seus anos reprodutivos.

Abstract Objective The present study aimed to develop a useful mathematical model that predicts the age at which premature ovarian insufficiency might occur after teletherapy radiation. A diagnosis of premature or early menopause has physical and psychological consequences, so women may need support and long-term medical follow-up. Methods To correlate ovarian radiation dose with ovarian function, we used the formula described by Wallace et al.: √g(z) = 10(2-0,15z), where “g(z)” and “z” represent oocyte survival rate and the radiation dose (in Gray), respectively. By simulating different ages and doses, we observed a pattern that could be used to simplify the relationship between radiation dose and remaining time of ovarian function. Results We obtained a linear function between ovarian radiation dose and loss of ovarian function (LOF) that is the percentage of decrease in the time to the ovarian failure compared with the time expected for a woman at the same age without irradiation exposition. For patients <40 years old and with ovarian radiation doses < 5 Gy, the equation LOF = 2.70 + (11.08 × Dose) can be applied to estimate the decrease in time to premature ovarian insufficiency. Conclusion The present study reports a practicable theoretical method to estimate the loss of ovarian function. These findings can potentially improve the management and counseling of young women patients submitted to radiotherapy during their reproductive years.

Resumo Dar más notícias é comum em obstetrícia e ginecologia. Porém, é difícil e poucos médicos recebem treinamento sobre como lidar com essa situação. Esta revisão narrativa tem como objetivo reunir, analisar e sintetizar parte do conhecimento sobre a área, com foco na obstetrícia. Dentre os 16 artigos selecionados, dois são estudos de intervenção randomizados e controlados, e a maioria dos estudos refere-se à obstetrícia. Os resultados encontrados ressaltaram que simulação, feedback/entrevistas, palestras e protocolos podem melhorar o desempenho dos médicos na comunicação de más notícias. Para os pacientes, o contexto e como as informações são transmitidas parecem ter maior impacto do que o conteúdo das notícias. Os obstetras e ginecologistas poderiam se beneficiar de cursos e protocolos específicos, dadas as particularidades da especialidade. Faltam evidências sobre a forma mais eficaz de realizar esse treinamento. Encontrar formas validadas de quantificar e classificar os resultados dos estudos na área, permitindo uma análise objetiva dos resultados, é um dos maiores desafios neste tema.

Abstract Breaking bad news is common in obstetrics and gynecology (ob-gyn). However, it is difficult, and few doctors receive training on how to deal with this situation. This narrative review aims to gather, analyze, and synthesize part of the knowledge on the area, focused on Ob-Gyn. Among the 16 selected articles, two are randomized controlled intervention studies, and most studies refer to obstetrics. The results found by us pointed out that simulation, feedback/debriefing, lectures, and protocols could improve doctors’ performance in communicating bad news. For patients, the context and how the information is transmitted seem to impact more than the content of the news. Ob-Gyn doctors could benefit from specific protocols and education, given the specialty’s particularities. There is a lack of evidence about the most effective way to conduct such training. Finding validated ways to quantify and classify studies’ results in the area, which would allow for the objective analysis of outcomes, is one of the biggest challenges concerning this topic.

Resumo Introdução Este estudo relata o caso de um carcinoma adenoide cístico (CAC) de glândula de Bartholin com transformação de alto grau. O CAC de glândula de Bartholin é um tumor raro, e sua transformação de alto grau é relatada somente em tumores de cabeça e pescoço. Relato de caso Paciente de 77 anos de idade, do sexo feminino, com lesão vulvar não ulcerada na topografia da glândula de Bartholin direita. A paciente foi submetida a ressecção do tumor e realização de retalho em V-Y, seguidas de radioterapia adjuvante. O exame histopatológico revelou CAC primário de glândula de Bartholin, com áreas de transformação de alto grau e invasão perineural. O estudo imunohistoquímico com p53 mostrou reação positiva difusa e intensa em áreas com transformação de alto grau. Após 24 meses de seguimento, a paciente apresentou metástases à distância e faleceu, apesar de ter sido submetida a quimioterapia. Conclusão Pelo que sabemos, este caso é a primeira descrição na literatura de transformação de alto grau em CAC de glândula de Bartholin, e a transformação de alto grau parece estar associada à agressividade do tumor.

Abstract Introduction In the present study, we report a case of primary adenoid cystic carcinoma (ACC) of the Bartholin gland with high-grade transformation (HGT). Adenoid cystic carcinoma of the Bartholin gland is a rare tumor and HGT has only been reported in head and neck tumors. Case Report A 77-year-old woman with a non-ulcerated vulvar lesion on the topography of the right Bartholin gland. The patient was submitted to tumor resection followed by V–Y island flap and adjuvant radiotherapy. The histopathological examination revealed primary ACC of the Bartholin gland, with areas of HGT and extensive perineural invasion. The immunohistochemical study with p53 showed a diffuse and strong positive reaction in areas with HGT. After 24 months of follow-up, the patient presented distant metastases and died, despite having undergone to chemotherapy. Conclusion As far as we know, this case is the first description in the literature of HGT in ACC of the Bartholin gland, and HGT appears to be associated with tumor aggressiveness.

RESUMO Mulheres portadoras de mutações nos genes BRCA 1 e 2 possuem risco aumentado para cânceres de ovário e mama e, portanto, são candidatas às cirurgias redutoras de risco, incluindo a salpingo-ooforectomia e a mastectomia. A salpingo-ooforectomia redutora de risco (SORR) é considerada a medida profilática mais efetiva para prevenção do câncer de ovário nesse grupo de pacientes. Esse procedimento implica a perda da função ovariana e menopausa induzida. A estrogenioterapia é o tratamento mais efetivo para o controle de sintomas vasomotores e melhora da qualidade de vida de mulheres no climatério. No entanto, a potencial estimulação hormonal desses tumores e o risco de câncer de mama constituem uma preocupação com a segurança da terapia hormonal (TH) nesta população. Este artigo tem como objetivo uma revisão das evidências atuais quanto aos benefícios potenciais e segurança da TH após SORR.

SUMMARY Women with mutations in the BRCA 1 and 2 genes are at increased risk for ovarian and breast cancer and therefore candidates for risk-reducing surgery, including salpingo-oophorectomy and mastectomy. Risk-reducing salpingo-oophorectomy (RRSO) is considered the most effective prophylactic measure for ovarian cancer prevention in this group of patients. This procedure involves loss of ovarian function and induced menopause. Estrogen therapy is the most effective treatment for controlling vasomotor symptoms and improving the quality of life of climacteric women. However, the potential hormonal stimulation of these tumors and the risk of breast cancer are a concern regarding the safety of hormone replacement therapy (HRT) in this population. This article aims to review the current evidence regarding the potential benefits and safety of HRT after RRSO.

Resumo Objetivo Opresente estudotemcomo objetivo obter informações demográficas básicas, o nível de interesse e de treinamento em ginecologia oncológica entre obstetras e ginecologistas (OB-GYNs) brasileiros para criar um perfil destes profissionais. Métodos Umquestionário online foi enviado a 16.008 ginecologistas filiados à Federação Brasileira de Associações de Ginecologia e Obstetrícia (FEBRASGO). Nós consideramos ginecologistas dedicados à oncologia ginecológica (OB-GYNsONCO) aqueles que referiram atuar em > 50% de sua prática diária com o tratamento do câncer feminino. Resultados Um total de 1.608 (10%) dos 16.008 membros da FEBRASGO responderam ao questionário. Os OB-GYNs estão concentrados nos estados do sul e sudeste do Brasil. A oncologia ginecológica foi considerada a 8ª área de maior interesse em ginecologia entre os OB-GYNs. Um total de 95 (5,9%) dos OB-GYNs foram considerados ginecologistas dedicados à oncologia ginecológica (OB-GYNs ONCO). Obstetras e ginecologistas estão ativamente envolvidos no tratamento do câncer: > 60% deles dedicam até 25% de sua prática diária à oncologia. O papel dosmédicos na triageme na prevenção, no diagnóstico, no tratamento de lesões pré-cancerosas e em procedimentos cirúrgicos de baixa complexidade é notavelmente alto. Ginecologistas dedicados à oncologia ginecológica no Brasil têm umperíodo de treinamento emoncologia ginecológica heterogêneo, não padronizado e curto. Estes profissionais tiveram um papel mais significativo na realização de operações de média e alta complexidade em comparação com OB-GYNs (65,2% versus 34%, e 47,3% versus 8,4%, respectivamente). Conclusão Os papéis dos OB-GYN e dos OB-GYNs ONCO parecem ser complementares. Os OB-GYNs frequentemente atuam emtriageme prevenção e em procedimentos cirúrgicos de baixa complexidade, enquanto os OB-GYNs ONCO estão mais envolvidos em casos demais alta complexidade. Estratégias para elevar os padrões de treinamento em oncoginecologia e incentivar o reconhecimento da oncologia ginecológica como uma subespecialidade devem ser adotadas no Brasil.

Abstract Objective The present study aims to obtain basic demographic information, the level of interest and of training in gynecology oncology among Brazilian obstetricians and gynecologists (OB-GYNs) to create a professional profile. Methods An online questionnaire was sent to 16,008 gynecologists affiliated to the Brazilian Federation of Associations of Gynecology and Obstetrics (FEBRASGO, in the Portuguese acronym). We considered gynecologists dedicated to gynecologic oncology (OB-GYNs ONCO) those who self-reported that > 50% of their daily practice consists in working with women’s cancer care. Results A total of 1,608 (10%) of 16,008 FEBRASGO members responded. The OBGYNs are concentrated in the southern and southeastern states of Brazil. Gynecologic oncology was considered the 8th greatest area of interest in gynecology among the OBGYNs. A total of 95 (5.9%) of the OB-GYNs were considered OB-GYNs ONCO. Obstetricians and gynecologists are actively engaged in cancer care: > 60% of them dedicate up to 25% of their daily practice to oncology. The role of the physicians in screening and prevention, diagnosis, in the treatment of precancerous lesions, and in low complexity surgical procedures is notably high. Gynecologists dedicated to gynecologic oncology in Brazil have a heterogeneous, nonstandardized and short training period in gynecologic oncology. These professionals had a more significantly role in performing medium- and high-complexity operations compared with OB-GYNs (65.2% versus 34%, and 47.3% versus 8.4%, respectively). Conclusion The role of OB-GYNs and of OB-GYNs ONCO appears to be complementary. Obstetricians and gynecologists actmore often in screening and prevention and in low-complexity surgical procedures, whereas OB-GYNs ONCO are more involved in highly complex cases. Strategies to raise standards in cancer training and to encourage the recognition of gynecologic oncology as a subspecialty should be adopted in Brazil.

Resumo Objetivo O presente estudo avaliou a expressão do WWOX, sua associação com características clinicopatológicas e com a expressão do p53, ki-67 (proliferação celular) e CD31 (angiogênese) em pacientes com carcinoma invasivo de células escamosas do colo uterino, ou simplesmente câncer do colo uterino (CCE). Métodos Foram avaliadas prospectivamente pacientes com CCE no estágio IB (n = 20) e mulheres com mioma uterino, no grupo controle (n = 20). As pacientes com CCE foram submetidas à histerectomia radical e à linfadenectomia pélvica do tipo B-C1. As mulheres no grupo-controle foram submetidas à histerectomia vaginal. As amostras de tecido foramcoradas comhematoxilina e eosina para avaliação histológica e a expressão das proteínas foi detectada por imuno-histoquímico. Resultados A expressão do WWOX foi significativamente menor no tumor quando comparada com sua expressão no colo do útero benigno (p = 0,019). A expressão tumoral de CD31 foi inversamente associada à expressão de WWOX (p = 0,018). Sua expressão não foi associada à expressão tumoral de p53 e Ki-67 em pacientes com CCE (p = 0,464 e p = 0,360, respectivamente). Não houve associação entre a expressão de WWOX e o tamanho do tumor (p = 0,156), grau de diferenciação (p = 0,914), presença de invasão vascular linfática (p = 0,155), comprometimento do paramétrio (p = 0,421) ou metástase dos linfonodos pélvicos (p = 0,310) em pacientes com CCE. Conclusão Os resultados sugeriram que o WWOX pode estar envolvido na carcinogênese do CICECU e esse marcador foi associado à angiogênese tumoral.

Abstract Objective The current study evaluated the expression of WW domain-containing oxidoreductase (WWOX), its association with clinicopathological features and with p53, Ki-67 (cell proliferation) and CD31 (angiogenesis) expression in patients with invasive cervical squamous cell carcinoma (ICSCC). To the best of our knowledge, no other study has evaluated this association. Methods Women with IB stage-ICSCC (n = 20) and women with uterine leiomyoma (n = 20) were prospectively evaluated. Patients with ICSCC were submitted to type BC1 radical hysterectomy and pelvic lymphadenectomy. Patients in the control group underwent vaginal hysterectomy. Tissue samples were stained with hematoxylin and eosin for histological evaluation and protein expression was detected by immunohistochemistry studies. Results The WWOX expression was significantly lower in the tumor compared with the expression in thebenign cervix (p = 0.019). TheWWOXexpressionwas inversely associated with the CD31 expression in the tumor samples (p = 0.018). There was no association betweentheWWOXexpression with the p53 expression (p = 0.464)or the Ki-67expression (p = 0.360) in the samples of invasive carcinoma of the cervix. There was no association between the WWOX expression and tumor size (p = 0.156), grade of differentiation (p = 0.914), presence of lymphatic vascular invasion (p = 0.155), parametrium involvement (p = 0.421) or pelvic lymph node metastasis (p = 0.310) in ICSCC tissue samples. Conclusion The results suggested that WWOX may be involved in ICSCC carcinogenesis, and this marker was associated with tumor angiogenesis.

PURPOSE: To evaluate the effects of letrozole (Ltz) in carcinogen+estrogen-induced endometrial hyperplasia. METHODS: BALB/c female mice were divided into four groups of 12 animals each receiving an intrauterine dose of N-ethyl-N-nitrosourea (ENU) and weekly subcutaneous injections of estradiol hexaidrobenzoate (EHB), except for group I(control). The groups were divided in I (control), II (ENU+EHB), III (ENU+EHB+MPA) and IV (ENU+EHB+Ltz). Group III also received intramuscular injections of MPA (medroxy progesterone acetate) every four weeks, while group IV received oral doses of Ltz daily. At the end of 16 weeks, the animals were sacrificed, and blood samples were collected for the measurement of serum estradiol and progesterone levels. Uterine histological sections were made to evaluate the presence of endometrial proliferative lesions. Differences between groups were evaluated with student's t test, ANOVA and chi-square test. RESULTS: Groups ENU+EHB, ENU+EHB+MPA and ENU+EHB+Ltz showed varying degrees of endometrial hyperplasia. The incidence of hyperplasia in groups ENU+EHB and ENU+EHB+Ltz was higher and more severe than in group ENU+EHB+MPA. Control group showed lower levels of serum estradiol than the other groups. CONCLUSION: There was no evidence that letrozole could act as an antiestrogenic drug in the development of endometrial proliferative lesions.