Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
1.
BMC Cancer ; 22(1): 263, 2022 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-35279106

RESUMEN

BACKGROUND: Ovarian cancer is initially responsive to frontline chemotherapy. Unfortunately, it often recurs and becomes resistant to available therapies and the survival rate for advanced and recurrent ovarian cancer is unacceptably low. We thus hypothesized that it would be possible to achieve more durable treatment responses by combining cisplatin chemotherapy with SW IV-134, a cancer-targeted peptide mimetic and inducer of cell death. SW IV-134 is a recently developed small molecule conjugate linking a sigma-2 ligand with a peptide analog (mimetic) of the intrinsic death pathway activator SMAC (second-mitochondria activator of caspases). The sigma-2 receptor is overexpressed in ovarian cancer and the sigma-2 ligand portion of the conjugate facilitates cancer selectivity. The effector portion of the conjugate is expected to synergize with cisplatin chemotherapy and the cancer selectivity is expected to reduce putative off-target toxicities. METHODS: Ovarian cancer cell lines were treated with cisplatin alone, SW IV-134 alone and a combination of the two drugs. Treatment efficacy was determined using luminescent cell viability assays. Caspase-3/7, - 8 and - 9 activities were measured as complementary indicators of death pathway activation. Syngeneic mouse models and patient-derived xenograft (PDX) models of human ovarian cancer were studied for response to SW IV-134 and cisplatin monotherapy as well as combination therapy. Efficacy of the therapy was measured by tumor growth rate and survival as the primary readouts. Potential drug related toxicities were assessed at necropsy. RESULTS: The combination treatment was consistently superior in multiple cell lines when compared to the single agents in vitro. The expected mechanism of tumor cell death, such as caspase activation, was confirmed using luminescent and flow cytometry-based assay systems. Combination therapy proved to be superior in both syngeneic and PDX-based murine models of ovarian cancer. Most notably, combination therapy resulted in a complete resolution of established tumors in all study animals in a patient-derived xenograft model of ovarian cancer. CONCLUSIONS: The addition of SW IV-134 in combination with cisplatin chemotherapy represents a promising treatment option that warrants further pre-clinical development and evaluation as a therapy for women with advanced ovarian cancer.


Asunto(s)
Antineoplásicos/uso terapéutico , Compuestos de Azabiciclo/uso terapéutico , Carcinoma Epitelial de Ovario/tratamiento farmacológico , Cisplatino/uso terapéutico , Oligopéptidos/uso terapéutico , Neoplasias Ováricas/tratamiento farmacológico , Animales , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Línea Celular Tumoral , Resistencia a Antineoplásicos , Femenino , Humanos , Ratones , Ratones Endogámicos C57BL
2.
Gynecol Oncol ; 162(3): 770-777, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34140179

RESUMEN

OBJECTIVE: To evaluate the ability of a personalized text-message-based intervention to increase weight loss among endometrial cancer survivors with obesity. METHODS: In this randomized, controlled trial, endometrial cancer survivors with obesity (BMI ≥30 kg/m2) were randomized to a personalized SMS text-message-based weight loss intervention or enhanced usual care. Primary outcome was weight loss at 6 months; secondary outcomes were weight loss at 12 months and changes in psychosocial measures. We also compared clinical characteristics and weight change between trial participants and non-participants. RESULTS: Between May 18 and December 31, 2017, 80 endometrial cancer survivors with obesity consented to participate in the randomized trial. There were no differences in clinical characteristics between the two arms. Weight changes were similar in the two arms (P = 0.08). At 6 months, no differences in quality of life, physical activity, or body image were noted. Of 358 eligible patients, 80 became trial participants and 278, non-participants. Trial participants were younger (59.3 vs. 63.4 years, P < 0.001), more likely non-white (P = 0.02), on fewer medications (4 vs. 7, P < 0.001), and had a higher median BMI (38.7 vs. 37.6 kg/m2, P = 0.01) than non-participants. Weight change was similar between participants and non-participants (P = 0.85). At 6 months, similar percentages of participants and non-participants (47.7% vs. 44.4%) had gained weight, and similar percentages (9.2% vs. 11.2%) had lost at least 5% of their body weight. CONCLUSIONS: This text-message-based intervention did not increase weight loss among endometrial cancer survivors with obesity, nor did participation in the trial. Other weight management interventions should be promoted to increase weight loss. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT03169023.


Asunto(s)
Neoplasias Endometriales/psicología , Ejercicio Físico , Obesidad/dietoterapia , Envío de Mensajes de Texto , Adulto , Anciano , Anciano de 80 o más Años , Índice de Masa Corporal , Supervivientes de Cáncer/psicología , Neoplasias Endometriales/complicaciones , Femenino , Humanos , Persona de Mediana Edad , Obesidad/complicaciones , Obesidad/psicología , Estudios Prospectivos , Calidad de Vida , Encuestas y Cuestionarios
3.
Gynecol Oncol ; 161(3): 700-704, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-33648746

RESUMEN

OBJECTIVE: To determine the association between scores from a 25-item patient-reported Rockwood Accumulation of Deficits Frailty Index (DAFI) and survival outcomes in gynecologic cancer patients. METHODS: A frailty index was constructed from the SEER-MHOS database. The DAFI was applied to women age ≥ 65 diagnosed with all types of gynecologic cancers between 1998 and 2015. The impact of frailty status at cancer diagnosis on overall survival (OS) was analyzed using Kaplan-Meier curves and Cox proportional hazards regression. RESULTS: In this cohort (n = 1336) the median age at diagnosis was 74 (range 65-97). Nine hundred sixty-two (72%) women were Caucasian and 132 (10%) were African-American. Overall, 651(49%) of patients were considered frail. On multivariate analysis, frail patients had a 48% increased risk for death (aHR 1.48; 95% CI 1.29-1.69; P < 0.0001). Each 10% increase in frailty index was associated with a 16% increased risk of death (aHR, 1.16; 95% CI, 1.11 to 1.21; P < 0.0001). In subgroup analyses of the varying cancer types, the association of frailty status with prognosis was fairly consistent (aHR 1.15-2.24). The DAFI was more prognostic in endometrial (aHR 1.76; 95% CI 1.41-2.18, P < 0.0001) and vaginal/vulvar (aHR 1.94; 95% CI 1.34-2.81, P = 0.0005) cancers as well as patients with loco-regional disease (aHR 1.94; 95% CI 1.62-2.33, P < 0.0001). CONCLUSIONS: Frailty appears to be a significant predictor of mortality in gynecologic cancer patients regardless of chronological age. This measure of functional age may be of particular utility in women with loco-regional disease only who otherwise would have a favorable prognosis.


Asunto(s)
Anciano Frágil , Fragilidad , Neoplasias de los Genitales Femeninos/mortalidad , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Bases de Datos Factuales , Etnicidad , Femenino , Neoplasias de los Genitales Femeninos/etnología , Humanos , Medicare , Valor Predictivo de las Pruebas , Modelos de Riesgos Proporcionales , Estudios Retrospectivos , Programa de VERF , Análisis de Supervivencia , Estados Unidos
4.
Gynecol Oncol ; 155(1): 88-92, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31375270

RESUMEN

OBJECTIVES: To estimate the frequency of abnormal surveillance cytology leading to high-grade dysplasia after surgical management for high-grade vulvar intraepithelial neoplasia (VIN) and vulvar cancer and to determine whether prior hysterectomy reduces this risk. METHODS: Women who underwent surgery for high-grade VIN or vulvar cancer between 2006 and 2014 were identified retrospectively. Patients who underwent prior hysterectomy for any indication were included. Univariate and multivariate logistic regression analyses were used to identify clinical correlates of abnormal cytology after surgical treatment for VIN and vulvar cancer. RESULTS: During a median follow-up for 72 months, 302 women underwent surveillance with cytologic screening after vulvar surgery including 99 (33%) women with prior hysterectomy. 75 (25%) women had abnormal cytology results. Of those, 47 (63%) were low-grade and 28 (37%) were high-grade, including 2 (3%) cases of invasive cancer. The rates of high-grade vaginal intraepithelial neoplasia (VAIN), cervical intraepithelial neoplasia (CIN), or cancer were not significantly different despite prior hysterectomy (9% VAIN 2+, 7% CIN 2+). Multivariate analysis showed that correlates of high-grade cytology following treatment for VIN or vulvar cancer included non-white race [odds radio (OR) 3.6, 95% confidence interval (CI) 1.7-7.8], prior abnormal cytology (OR 3.5, 95% CI 1.6-7.6), and immunodeficiency (OR 3.4, 95% CI 1.3-8.8). Prior hysterectomy did not significantly decrease risk of high-grade cytology (OR 0.87, 95% CI 0.5-1.6). CONCLUSIONS: Women treated surgically for VIN/vulvar cancer have an 8% risk of at least high-grade dysplasia from surveillance screening and prior hysterectomy does not mitigate the risk. Extrapolating from current guidelines, we recommend surveillance cytology screening at least 6-12 months after treatment.


Asunto(s)
Carcinoma in Situ/cirugía , Lesiones Precancerosas/patología , Displasia del Cuello del Útero/patología , Enfermedades Vaginales/patología , Neoplasias de la Vulva/cirugía , Carcinoma in Situ/epidemiología , Carcinoma in Situ/patología , Femenino , Estudios de Seguimiento , Humanos , Persona de Mediana Edad , Clasificación del Tumor , Lesiones Precancerosas/epidemiología , Estudios Retrospectivos , Displasia del Cuello del Útero/epidemiología , Enfermedades Vaginales/epidemiología , Neoplasias de la Vulva/epidemiología , Neoplasias de la Vulva/patología , Washingtón/epidemiología
5.
Gynecol Oncol ; 155(1): 105-111, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31383570

RESUMEN

BACKGROUND: Ovarian cancer is the deadliest gynecologic malignancy, yet the effects on survival of modifiable pre-diagnosis lifestyle factors, such as obesity and physical activity, remain largely unexplored. Our objective was to evaluate the effect of pre-diagnosis BMI and physical activity on ovarian cancer mortality using prospectively collected data. METHODS: Data on women who developed ovarian cancer after enrollment into the NIH-AARP Diet and Health Study were analyzed. Cancer incidence was ascertained through linkage state cancer registries and consisted of 741 cases of epithelial ovarian cancer. RESULTS: Higher pre-diagnosis BMI was associated with increased overall and ovarian cancer-specific mortality. Comparing women with BMI 25-29.9, 30-34.9 and ≥ 35 to normal weight women, the HRs of overall mortality were 1.18 (95%CI 0.96-1.45), 1.05 (0.82-1.36) and 1.59 (1.14-2.18, p-trend = 0.02). The findings were similar for ovarian cancer-specific mortality comparing women with BMI ≥ 35 to normal weight women (BMI <25) with a HR of 1.47 (95%CI 1.03-2.09, p-trend 0.08). Pre-diagnosis physical activity was not associated with mortality, with HRs for overall mortality of 1.06 (95%CI 0.79-1.43), 0.94 (0.72-1.23), 0.98 (0.76-1.25), and 0.98 (0.75-1.28, p-trend = 0.91), comparing women who engaged in vigorous physical activity 1-3 times/month, 1-2 times/week, 3-4 times/week and 5 times/week, respectively, with those who never/rarely engaged in such activity. CONCLUSIONS: Women who were obese before developing ovarian cancer had increased mortality than those who were normal weight, but physical activity before diagnosis was not associated with mortality in this study population. These results suggest that maintaining a healthy weight is a powerful preventative tool.


Asunto(s)
Índice de Masa Corporal , Carcinoma Epitelial de Ovario/mortalidad , Ejercicio Físico , Neoplasias Ováricas/mortalidad , Anciano , Femenino , Humanos , Incidencia , Persona de Mediana Edad , Modelos de Riesgos Proporcionales , Sistema de Registros , Estados Unidos/epidemiología
7.
Gynecol Oncol Rep ; 51: 101315, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38205237

RESUMEN

Objectives: Cervical cancer has markedly declined due to widespread use of screening, but Hispanic women continue to bear a disproportionate amount of the cervical cancer burden due to under-screening. Previous studies have explored barriers to screening but have failed to identify targetable facilitators in this group. We aimed to assess facilitators to cervical cancer screening among a predominantly urban, Hispanic population who presented to a no-cost, community-based clinic. Methods: Patients completed demographic and health information, a validated social determinants of health (SDOH) screen, and a self-reported facilitators survey on factors which enabled them to present to clinic. Descriptive statistics were conducted to assess patients' sociodemographic characteristics, SDOH, and perceived facilitators. Results: 124 patients were included. 98 % were Hispanic, 90 % identified Spanish as their preferred language, and 94 % had no insurance. Median age was 41. 31 % of patients reported a history of abnormal screening. On SDOH, over 80 % of patients screened positive in at least one domain, with the most common being food insecurity (53 %) and stress (46 %). The most frequently reported facilitator was encouragement from a family member/friend (30 %). 26 % of patients reported time off from work and 25 % reported availability of child/elder care as facilitators. Conclusions: Identifying facilitators among patients who present for cervical cancer screening is critical to designing care plans to reach all populations. Our survey showed that the single greatest facilitator to patients presenting for cervical cancer screening was encouragement from a family member/friend. These findings suggest that increasing community involvement and awareness may help to improve cervical cancer screening in a minority, urban, underserved population.

8.
Gynecol Oncol Rep ; 44: 101075, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36217326

RESUMEN

Objective: Given the importance of understanding neighborhood context and geographic access to care on individual health outcomes, we sought to investigate the association of community primary care (PC) access on postoperative outcomes and survival in ovarian cancer patients. Methods: This was a retrospective cohort study of Stage III-IV ovarian cancer patients who underwent surgery at a single academic, tertiary care hospital between 2012 and 2015. PC access was determined using a Health Resources and Services Administration designation. Outcomes included 30-day surgical and medical complications, extended hospital stay, ICU admission, hospital readmission, progression-free and overall survival. Descriptive statistics and chi-squared analyses were used to analyze differences between patients from PC-shortage vs not PC-shortage areas. Results: Among 217 ovarian cancer patients, 54.4 % lived in PC-shortage areas. They were more likely to have Medicaid or no insurance and live in rural areas with higher poverty rates, significantly further from the treating cancer center and its affiliated hospital. Nevertheless, 49.2 % of patients from PC-shortage areas lived in urban communities. Residing in a PC-shortage area was not associated with increased surgical or medical complications, ICU admission, or hospital readmission, but was linked to more frequent prolonged hospitalization (26.3 % vs 14.1 %, p = 0.04). PC-shortage did not impact progression-free or overall survival. Conclusions: Patients from PC-shortage areas may require longer inpatient perioperative care in order to achieve the same 30-day postoperative outcomes as patients who live in non-PC shortage areas. Community access to PC is a critical factor to better understanding and reducing disparities among ovarian cancer patients.

9.
Gynecol Oncol Rep ; 35: 100694, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33490354

RESUMEN

It is unclear if surveillance for postmenopausal women with medically inoperable stage 1 endometrial cancer (EC) should differ depending on their management strategy. Thus, we investigated the utility of surveillance endometrial sampling among 53 postmenopausal women with medically inoperable, clinical stage I, grade 1 endometrioid EC who received either progestin therapy or radiation between 2009 and 2018, at a single academic institution. Frequency and results of endometrial sampling, as well as recurrence and survival rates were studied. Of 53 patients, 18 (34.0%) received progestin therapy and 35 (66.0%) radiation. Medically managed patients were treated with megestrol acetate (27.7%), a levonorgestrel intrauterine device (27.7%), or both (44.4%). Radiated patients were mostly treated with high-dose rate brachytherapy only (77.1%). Surveillance endometrial sampling (median procedures = 4, range 1-10) was strictly adhered to among all patients who received progestin therapy, but infrequently (6/35, 17.1%) performed among radiated patients, yielding no positive results. Three recurrences occurred over the median follow-up of 38 months. Two (11%) women in the progestin therapy group recurred locally and were diagnosed by endometrial sampling. One (3%) patient in the radiation group recurred distally in the lung 25.3 months after completing brachytherapy. We conclude that appropriate surveillance for women with medically inoperable, clinical stage I, grade 1 EC depends on the management strategy. For those treated with progestins, surveillance with endometrial sampling every 3-6 months can reveal local recurrence. However, given the excellent local control after radiation, endometrial sampling may not be warranted for women treated with definitive radiation.

10.
Gynecol Oncol Rep ; 36: 100719, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33665293

RESUMEN

We aimed to evaluate obese endometrial cancer (EC) survivors' perceptions of weight loss barriers and previously attempted weight loss methods and to identify characteristics that predicted willingness to enroll in a behavioral intervention trial. We administered a 27-question baseline survey at an academic institution to EC survivors with body mass index ≥ 30 kg/m2. Survivors were asked about their lifestyles, previous weight loss attempts, perceived barriers, and were offered enrollment into an intervention trial. Data was analyzed using Fisher's Exact, Kruskal-Wallis, and univariate and multivariate regressions. 155 of 358 (43%) eligible obese EC survivors were surveyed. Nearly all (n = 148, 96%) had considered losing weight, and 77% (n = 120) had tried two or more strategies. Few had undergone bariatric surgery (n = 5, 3%), psychologic counseling (n = 2, 1%), or met with physical therapists (n = 9, 6%). Lower income was associated with difficulty in accessing interventions. Survivors commented that negative self-perceptions and difficulties with follow-through were barriers to weight loss, and fear of complications and self-perceived lack of qualification were deterrents to bariatric surgery. 80 (52%) of those surveyed enrolled in the trial. In a multivariate model, adjusting for race and stage, survivors without recurrence were 4.3 times more likely to enroll than those with recurrence. Most obese EC survivors have tried multiple strategies to lose weight, but remain interested in weight loss interventions, especially women who have never experienced recurrence. Providers should encourage weight loss interventions early, at the time of initial diagnosis, and promote underutilized strategies such as psychological counseling, physical therapy, and bariatric surgery.

11.
J Glob Oncol ; 5: 1-5, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-31067142

RESUMEN

PURPOSE: Despite being the only hospital to provide comprehensive cervical cancer treatment to many medically underserved Guatemalan women, no assessment of the cervical cancer patient population at the Guatemala Cancer Institute has been performed. To understand the demographics of the patient population, their treatment outcomes, and access to care, we sought to assess treatment compliance of patients with cervical cancer at the Guatemala Cancer Institute and its effects on patient outcomes. METHODS: A retrospective chart review was conducted of patients with cervical cancer between 2005 and 2007 and assessed for follow-up through December 2015. Demographics and clinical characteristics were tabulated. A Kaplan-Meier curve to model compliance was generated. RESULTS: Ninety-two patients with invasive cancer were analyzed. Most presented with squamous cell carcinoma (73%) and at locally advanced stages (IIB, 51%; IIIB, 33%). Most (75 of 92, 81.5%) initiated treatment after diagnosis, but 18.5% (17 of 92) were lost to follow-up before treatment initiation. For treatment, 97% received external beam radiation, 84% brachytherapy, and 4% concomitant chemotherapy. Nearly 20% of patients were lost to follow-up in the first 6 months and 65% in the first 5 years. Of the 67 patients who completed treatment, only 15 (16% of the initial cohort) were diagnosed with a recurrence. No deaths were recorded. CONCLUSION: The low recurrence rate and no documented deaths suggest a correlation with the low compliance rate and poor follow-up. This finding highlights the need to examine more fully the barriers to compliance and access to care among this population to optimize the treatment of cervical cancer.


Asunto(s)
Cooperación del Paciente/psicología , Neoplasias del Cuello Uterino/psicología , Neoplasias del Cuello Uterino/terapia , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma de Células Escamosas/epidemiología , Carcinoma de Células Escamosas/patología , Carcinoma de Células Escamosas/psicología , Carcinoma de Células Escamosas/terapia , Quimioradioterapia , Femenino , Guatemala/epidemiología , Humanos , Perdida de Seguimiento , Persona de Mediana Edad , Recurrencia Local de Neoplasia/epidemiología , Recurrencia Local de Neoplasia/patología , Recurrencia Local de Neoplasia/psicología , Recurrencia Local de Neoplasia/terapia , Estadificación de Neoplasias , Aceptación de la Atención de Salud/psicología , Aceptación de la Atención de Salud/estadística & datos numéricos , Cooperación del Paciente/estadística & datos numéricos , Estudios Retrospectivos , Resultado del Tratamiento , Neoplasias del Cuello Uterino/epidemiología , Neoplasias del Cuello Uterino/patología , Adulto Joven
12.
Gynecol Oncol Rep ; 29: 106-110, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31467962

RESUMEN

It is unclear if endometrial cancer (EC) patients are aware of their modifiable risk factors. We administered a 33-item questionnaire to EC patients at a university-based cancer center to assess their understanding of how comorbidities and lifestyle/sexual behaviors impact their cancer risk. We also inquired about their access to a primary care physician (PCP). Pearson's χ2 test or Fisher's exact test were used to assess differences in understanding based on a dichotomized Charlson comorbidity score, <7 vs ≥7. Of the 50 surveyed women (81% response rate), 39 reported hypertension (80%) and 36 (72%) diabetes. All had a PCP. Most were aware that obesity contributes to diabetes (43/48, 90%), hypertension (42/48, 88%), and heart attack (42, 88%), but only 19/49 (39%) knew that EC is more common in overweight/obese women. More than half lacked understanding of the following risks including modifiable risk factors-unhealthy diet (31, 62%), hormone replacement therapy (38, 76%), alcohol (30, 60%), and the protective effects of cigarette smoking (38, 76%). Most also incorrectly identified the following sexual health factors as risks for EC: early coitarche (30, 60%), or having an abortion (27, 54%), a sexually transmitted infection (35, 70%) or human immunodeficiency virus (34, 68%). Although EC patients recognize that obesity is linked to comorbidities, less than half are aware that it contributes to their cancer risk. Furthermore, responses to lifestyle/sexual health behaviors suggest women may lack understanding of global differences between endometrial and cervical cancer risk factors.

13.
Gynecol Oncol Rep ; 22: 48-51, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-29234709

RESUMEN

Our objective was to assess overall survival of cervical cancer patients following prior platinum/bevacizumab chemotherapy, comparing retreatment with platinum/bevacizumab with alternative therapies. A retrospective analysis was performed of women who received platinum/bevacizumab (PB) chemotherapy for cervical cancer at Washington University between July 1, 2005 and December 31, 2015. Wilcoxon rank-sum exact test and Fisher's exact test were used to compare the treatment groups, and Kaplan Meier curves were generated. Cox regression analyses were performed, with treatment free interval and prior therapy response included as covariates. Of 84 patients who received PB chemotherapy, 59 (70%) received no second line chemotherapy, as they did not recur, progressed without further chemotherapy, were lost to follow up, or expired. Of the remaining 25 patients, 9 were retreated with the combination of platinum/bevacizumab (PB), 6 were retreated with a platinum regimen without bevacizumab (P), and 10 were retreated with neither (not-P). The only long-term survivor was in the not-P group and was treated with an immunotherapy agent. Median overall survival of all patients was 7.1 months. There was a marginal difference in survival between women in the PB and not-PB groups (11.8 versus 5.7 months; HR 3.02, 95% CI, 0.98-9.28). There was no difference in survival based on platinum interval (HR 0.81; 95% CI, 0.27-2.45). Outcomes are grim for women retreated after platinum/bevacizumab therapy and are only marginally improved by retreatment with a platinum/bevacizumab regimen. Rather than additional PB therapy, women with cervical cancer who recur after platinum/bevacizumab should consider supportive care or clinical trials.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA