Abstract 5888: Trends in incidence of gallbladder cancer in all 50 United States from 2001 to 2018

Background: Gallbladder cancer (GBC) is an aggressive malignancy of the gastrointestinal system that is historically more common among racial/ethnic minority populations in the US. We investigated trends in GBC incidence rates in all 50 states from 2001 to 2018, overall and stratified by race/ethnicity, sex, and different regions.

Methods: Age-standardized incidence rates and trends in adults aged ≥35 years were calculated using data from the U.S. Cancer Statistics registry. We used joinpoint regression to compute annual percent changes (APC) and average annual percent changes (AAPC) and corresponding 95% confidence intervals (CI) for both sexes and used eleven 5-year age groups (35-39 years through 85+ years). Race/ethnic groups were classified as non-Hispanic Whites and Blacks (NHWs and NHBs), Hispanics, American Indians/Alaska Natives, and Asians and Pacific Islanders.

Results: Overall, the age-standardized incidence rate for GBC decreased by 0.3% annually between 2001 and 2018 (95% CI -0.5%, -0.1%). However, secular trends varied by age-group, sex and race/ethnicity. APC increased among individuals aged 45-54 years from 1.2% to 1.4% but decreased among those who were ≥ 75 years (-0.7% to -1.6% per year). While GBC incidence rates were stable among men between 2001 and 2014, incidence rates decreased by over 2% per year between 2014 and 2018 (APC, -2.1%; 95%CI: -3.9, -0.3). GBC incidence remained relatively stable between 2001 and 2018 among women. While GBC rates declined in other racial/ethnic groups, the rates increased by 1.4% annually among non-Hispanic Blacks (NHBs) between 2001 and 2018 (APC=1.4%; 95%CI: 0.9%, 2.0%). Among NHBs, increasing trends were also noted in Northeast, Midwest, and South regions of US.

Conclusions: The study shows increasing incidence trends for GBC in the US among NHBs from 2001-2018 compared to decreasing trends among other race/ethnic groups. The results also point to the need for studying equitable detection and treatment of underlying risk factors for GBC.

Citation Format: Syed A. Raza, Wilson L. Costa, Aaron P. Thrift. Trends in incidence of gallbladder cancer in all 50 United States from 2001 to 2018 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5888.

Impact of anticoagulation on recurrent thrombosis and bleeding after hematopoietic cell transplantation

History of venous thromboembolism (VTE) is prevalent among patients undergoing hematopoietic cell transplantation (HCT). Management of anticoagulation is particularly challenging as most patients will have chemotherapy-induced thrombocytopenia while awaiting engraftment post-HCT. We conducted a retrospective study of autologous and allogeneic HCT recipients with prior VTE from 2006-2015 to 1) compare anticoagulant strategies on short-term VTE recurrence and bleeding and 2) assess predictors for VTE recurrence beyond 30 days. Patients with VTE were allocated to two cohorts based on anticoagulant strategy at thrombocytopenia onset and underwent inverse probability weighting to assess primary outcomes of VTE recurrence and bleeding within 30 days post-HCT. Subsequently, multivariable logistic regression model was used to assess the association of 100-day VTE recurrence by the HIGH-2-LOW VTE risk assessment score and whether patients resumed anticoagulation at platelet recovery. Thirteen percent of recipients had VTE prior to HCT; of those meeting inclusion criteria, 227 continued anticoagulation and 113 temporarily discontinued it. Anticoagulant strategy was not significantly associated with decreased risk of VTE recurrence within 30 days (3% vs 4%, p = 0.61); however, risk of overall bleeding was non-significantly higher in those who continued vs discontinued anticoagulation (41% vs 31%, p = 0.08). In a subgroup of 250 allogeneic HCT patients, every one-point increase of HIGH-2-LOW score was significantly associated with VTE recurrence at 100 days (OR 1.57 [95% CI 1.10-2.23]), while anticoagulation resumption upon platelet engraftment was associated with lower recurrent risk (OR 0.48 [0.20-1.14]). Temporarily withholding anticoagulation during thrombocytopenia may optimize risk-benefit tradeoffs, though additional strategies are essential to prevent VTE recurrence after hematopoietic recovery.

Brazilian Group of Gastrointestinal Tumours' consensus guidelines for the management of oesophageal cancer

Oesophageal cancer is among the ten most common types of cancer worldwide. More than 80% of the cases and deaths related to the disease occur in developing countries. Local socio-economic, epidemiologic and healthcare particularities led us to create a Brazilian guideline for the management of oesophageal and oesophagogastric junction (OGJ) carcinomas. The Brazilian Group of Gastrointestinal Tumours invited 50 physicians with different backgrounds, including radiology, pathology, endoscopy, nuclear medicine, genetics, oncological surgery, radiotherapy and clinical oncology, to collaborate. This document was prepared based on an extensive review of topics related to heredity, diagnosis, staging, pathology, endoscopy, surgery, radiation, systemic therapy (including checkpoint inhibitors) and follow-up, which was followed by presentation, discussion and voting by the panel members. It provides updated evidence-based recommendations to guide clinical management of oesophageal and OGJ carcinomas in several scenarios and clinical settings.

Predictors of long-term survival in patients with hepatic resection of colorectal metastases: Analysis of a Brazilian Cancer Center Cohort

BACKGROUND

Hepatic metastases are a major cause of death in patients with colorectal cancer. A comprehensive assessment of the prognostic factors associated with long-term survival could improve patient selection for surgical approaches and decrease morbidity and futile locoregional treatments.

METHODS

We performed a retrospective analysis of patients who underwent hepatectomy for colorectal liver metastases at a single center from 2000 to 2012.

RESULTS

To identify factors associated with 5- and 10-year overall (OS) and disease-free survival (DFS), we analyzed 280 patients and 150 patients in the 5- and 10-year cohorts, respectively. Only seven relapses occurred after 5 years of follow-up, and no relapses occurred after 10 years. Multivariable analysis indicated that bilobar disease and extra-hepatic disease before hepatectomy were independent 5- and 10-year predictors of OS, and major postoperative complications predicted OS in the 5-year survival cohort only. Our analysis indicated that prognostic factors associated with DFS included some confounders and was therefore inconclusive.

CONCLUSIONS

Taken together, our results suggest that the predictors of 5- and 10-year OS rates of colorectal cancer patients with hepatic metastases are similar, differing only by postoperative complications that influenced exclusively 5-year survival. Since no relapse occurred 10 years after hepatic resection, oncological remission is likely.

Survival of gastric cancer (GC) patients is not determined by the predominant genomic ancestry (PGA): Results from an ethnically admixed Brazilian cohort of GC patients

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Background: Clinical characteristics, treatment response and overall survival of GC patients differ between Asian and non-Asian countries. Here we evaluated the possible associations between PGA, clinical characteristics and survival in an admixed GC Brazilian cohort. Methods: We included 112 GC pts diagnosed and treated at AC Camargo Cancer Center (São Paulo, Brazil) before 2013. The study was approved by local IRB. Genomic DNA was used for capture-based enrichment of a customized gene panel including 99 genes. Libraries were sequenced in the NextSeq 500 platform (Illumina), using paired-end reads (2x75bp). Ancestries were determined through a set of ancestry informative markers (AIMs), covered by target and off-target reads, described by Elhaik et al. (2014). Results: An average of 406 AIMs were recovered from the available samples, revealing average ancestries was as follows: 55.4% European, 27.7% Asian, 8.9% African; 8% of subjects were highly admixed (HA; < 50% of any ancestry). We found no association between PGA and age at diagnosis (p = 0.58), tumor location (p = 0.34), Lauren (p = 0.24) and staging (p = 0.68). There was an association between PGA and gender (p = 0.04) and a marginal association between PGA and EBV (p = 0.056). BRCA2 was the only gene enriched in the Asian subgroup, compared to the other groups combined (p = 0.009). The median follow-up time was 95 months. We found no differences in median overall survival (OS) (p = 0.4) or disease-free survival (DFS) (p = 0.6) according to PGA. The HA subgroup presented worst survival outcomes compared to the other groups aggregated (mOS 34m; 95%CI 5-80 x mOS 71m; 95% CI 44-85, respectively), but the difference was not statistically significant (HR 1,73; 95% CI 0.74-4.05; p = 0.2). Even for patients with > 75% AIMs for any given ancestry, we found no differences in OS between Europeans (n = 25; mOS 86m; 95%CI 80-NA), Asians (n = 22; mOS 83m; 95%CI 51-NA) and Africans (n = 5; mOS 67m; 95%CI 22-NA), p = 0.4. Conclusions: The most prevalent ancestries in this Brazilian GC cohort were European, followed by Asian and African. Although we found associations between ancestry and a few clinical aspects, PGA was not associated with survival.

Evaluation of the outcome of adjuvant treatment for gastric cancer in Brazil and Peru: A retrospective study in two cancer centers in Latin America

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Background: Gastric cancer (GC) is one of the most frequent malignancies in developing countries. In Peru, it is the fourth most incident cancer, and the sixth one in Brazil. Mortality is still high. The chance of relapse of patients with non-metastatic disease undergoing surgery is more than 50%. It is suspected that Latin American patients present worse evolution compared to those treated in Asia or in developed countries, therefore it is fundamental to study factors related to the prognosis and evolution of patients with GC in our continent. We aimed to evaluate the outcome of adjuvant treatment for GC in patients from two countries with different racial miscegenation and eating habits, and correlate this with clinicopathological features. Methods: We retrospectively analyzed 187 patients with GC who underwent curative surgery and received CRT at AC Camargo Cancer Center (ACCCC) in Brazil and Instituto Nacional de Enfermedades Neoplasicas (INEN) in Peru. CRT was defined as MacDonald protocol. Primary endpoint was overall survival (OS). Cox regression model was performed in order to calculate hazard ratio (HR) and 95% confidence intervals (95%CI). Results: Median follow up time was 51 and 20 months in Brazil and Peru, respectively. Median age of our cohort was 54 years-old. Male sex was predominant in both countries (Brazil: 54.7%; Peru: 56.9%). Diffuse subtype also was predominant (Brazil: 58.3%; Peru: 55.1%). Median OS was 103.9 and 45.2 months in Brazil and Peru respectively (p < 0.001). In the multiple analysis, we found that pathological stage (I/II vs. III; HR = 4.1, 95%CI 1.4-11.7; p = 0.009) was independent prognostic factor adjusted by country of treatment, histological subtype, localization, age and gender. Conclusions: Survival differences exist between Brazil and Peru. We observed that patients from Peru had more advanced pathological stage after surgery. This difference suggests a possible prognostic factor in OS. Ethnic/genetic factors, eating habits and other clinicopathological or molecular factors may also explain different prognosis. Future studies are warranted to determine these prognostic factors in Latin American gastric cancer patients.

HER-2 overexpression in gastroesophageal junction (EGJ) adenocarcinoma as a predictor of prognosis in patients treated with perioperative chemotherapy

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Background: Approximately 15% of all gastroesophageal adenocarcinomas overexpress HER-2. This is more common in intestinal subtype and proximal tumors. HER-2 status is associated with poor prognosis in non-metastatic patients, but its prognostic impact on the outcomes of pts treated with perioperative chemotherapy (CT) is unclear. Methods: The aim of this study was to retrospectively analyze the influence of HER-2 status on the overall survival (OS) and Relapse Free Survival (RFS) of pts with locally advanced gastroesophageal adenocarcinoma treated with perioperative CT. HER-2 positive tumors were defined by 3+ immunohistochemical staining or fluorescence in situ hybridization positivity. Independent variables used in the Cox model were: Lauren's subtype, clinical staging, and a combination of primary site and HER-2 status. Results: A total of 97 patients were included: median age was 62y, 62 (63.9%) were male; N = 57 (58.8%) had cT3 tumors and 60 (60.1%) had cN+. Lauren’s subtype was intestinal in N = 35 (36.1%), and diffuse in N = 44 (45.4%). CT regimens were mainly FOLFOX (46.4%), EOX (23.7%) or DCF (13.4%). Regarding primary site and HER-2 status: gastric HER-2 negative N = 61, Gastric HER-2 positive N = 8, GEJ HER-2 negative N = 23, GEJ HER-2 positive N = 5. In a Cox multivariate analyses for OS and RFS, EGJ HER-2 positive pts had higher chance of recurrence (HR = 3.57, 1.08 – 11.77, p = 0.03) and death (HR = 6.14, 1.83 – 20.60, p = 0.003). EGJ HER-2+ 3y RFS was zero and 3y OS was 20%. Conclusions: EGJ HER-2+ tumors carried a dismal prognosis and had little benefit from conventional perioperative CT strategies. Although further studies are needed to confirm our data, we believe that a different approach, possible combining anti-HER-2 drugs, should be tested in this scenario.

Pancreatic mucinous cystadenoma with serum CA 19-9 over 1,000,000 U/mL: a case report and review of the literature

BACKGROUND

The diagnosis of pancreatic cystic neoplasms has become more accurate recently. In some cases, however, doubt remains regarding the lesion's malignant potential. CA 19-9 has long been identified as a reliable biomarker in differentiating pancreatic benign and malignant lesions, especially in non-jaundiced patients.

CASE REPORT AND DISCUSSION

We report a case of a young female who presented with a mucinous lesion in the tail of the pancreas and a serum CA 19-9 over 1,000,000 U/mL. She was taken to surgery and had a distal pancreatectomy and splenectomy. Pathology reports showed only a mucinous cystadenoma. After 1 year of follow-up, her serum CA 19-9 was normal. Following that, the work-up in these lesions, the role of the biomarker in pancreatic adenocarcinoma and in the differentiation between benign and malignant lesions is discussed.

Extended preoperative chemotherapy, extent of liver resection and blood transfusion are predictive factors of liver failure following resection of colorectal liver metastasis

AIM

The aim of this study was to determine the incidence and prognostic factors of postoperative liver failure in patients submitted to liver resection for colorectal metastases.

METHOD

Patients with CLM who underwent hepatectomy from 1998 to 2009 were included in retrospective analysis. Postoperative liver failure was defined using either the 50-50 criteria or the peak of serum bilirubin level above 7 mg/dL independently.

RESULTS

Two hundred and nine (209) procedures were performed in 170 patients. 120 surgeries were preceded by chemotherapy within six months. The overall morbidity rate was 53.1% and 90-day mortality was 2.3%. Postoperative liver failure occurred in 10% of all procedures, accounting for a mortality rate of 9.5% among this group of patients. In multivariate analysis, extent of liver resection, need of blood transfusion and more than eight preoperative chemotherapy cycles were independent prognostic factors of postoperative liver insufficiency. This complication was not related with the chemotherapy regimen used.

CONCLUSION

We conclude that postoperative liver failure has a relatively low incidence (10%) after CLM resection, but a remarkable impact on postoperative mortality rate. The amount of liver resected, the need of blood transfusion and extended preoperative chemotherapy are independent predictors of its occurrence and this knowledge can be used to prevent postoperative liver failure in a multidisciplinary approach.

Adjuvant chemoradiotherapy after d2-lymphadenectomy for gastric cancer: the role of n-ratio in patient selection. results of a single cancer center

Background

Adjuvant chemoradiotherapy is part of a multimodality treatment approach in order to improve survival outcomes after surgery for gastric cancer. The aims of this study are to describe the results of gastrectomy and adjuvant chemoradiotherapy in patients treated in a single institution, and to identify prognostic factors that could determine which individuals would benefit from this treatment.

Methods

This retrospective study included patients with pathologically confirmed gastric adenocarcinoma who underwent surgical treatment with curative intent in a single cancer center in Brazil, between 1998 and 2008. Among 327 patients treated in this period, 142 were selected. Exclusion criteria were distant metastatic disease (M1), T1N0 tumors, different multimodality treatments and tumors of the gastric stump. Another 10 individuals were lost to follow-up and there were 3 postoperative deaths. The role of several clinical and pathological variables as prognostic factors was determined.

Results

D2-lymphadenectomy was performed in 90.8% of the patients, who had 5-year overall and disease-free survival of 58.9% and 55.7%. The interaction of N-category and N-ratio, extended resection and perineural invasion were independent prognostic factors for overall and disease-free survival. Adjuvant chemoradiotherapy was not associated with a significant improvement in survival. Patients with node-positive disease had improved survival with adjuvant chemoradiotherapy, especially when we grouped patients with N1 and N2 tumors and a higher N-ratio. These individuals had worse disease-free (30.3% vs. 48.9%) and overall survival (30.9% vs. 71.4%).

Conclusion

N-category and N-ratio interaction, perineural invasion and extended resections were prognostic factors for survival in gastric cancer patients treated with D2-lymphadenectomy, but adjuvant chemoradiotherapy was not. There may be some benefit with this treatment in patients with node-positive disease and higher N-ratio.

Safety and preliminary results of perioperative chemotherapy and hyperthermic intraperitoneal chemotherapy (HIPEC) for high-risk gastric cancer patients

Background

Gastric cancer relapse occurs in about 30% of the patients treated with gastrectomy and D2-lymphadenectomy, mainly as distant or peritoneal metastases. Hyperthermic intraperitoneal chemotherapy (HIPEC) has been associated with an improvement in survival and lower peritoneal recurrence, albeit with increased morbidity. The aim of this study is to report the preliminary results of the association of perioperative chemotherapy, radical surgery and HIPEC in high-risk gastric patients in a single institution.

Methods

Treatment protocol was started in 2007 and included patients younger than 65 years old, with good performance status and gastric adenocarcinoma with serosa involvement and lymph node metastases, located in the body or antrum. Patients should receive three preoperative cycles of DCF (Docetaxel 75 mg/m², Cisplatin 75 mg/m² and continuous intravenous infusion of 5-Fluorouracil 750 mg/m² for 5 days), followed by gastric resection with D2-lymphadenectomy, hyperthermic intraperitoneal chemotherapy with Mytomicin C 34 mg/m² and three more postoperative cycles of DCF.

Results

Ten patients were included between 2007 and 2011. Their median age was 47 years old and six were male. Nine were staged with cT4 cN + tumors and one as cT3 cN+. Nine patients completed all three preoperative chemotherapy cycles. Eight individuals were treated with a total gastrectomy and the other two had a distal gastrectomy, all having HIPEC. Postoperative morbidity was 50%, with no deaths. Regarding postoperative chemotherapy, only 5 patients completed three cycles. With a median follow-up of 25 months, three relapses were identified and 7 patients remain disease-free, two with more than 4 years of follow-up.

Conclusion

The association of perioperative systemic and intraperitoneal chemotherapy plus radical surgery is a feasible multimodality treatment, with acceptable morbidity. With a longer follow-up and a larger group of patients, we hope to be able to determine if it also influences survival outcomes and patterns of recurrence.

Mini-Abstract

The association of perioperative chemotherapy, gastric resection and D2-lymphadenectomy and hyperthermic intraperitoneal chemotherapy proved to be associated with acceptable morbidity. For survival analysis, a longer follow-up is needed.

HER2 status and histopathologic findings related to tumor regression in gastric carcinomas treated with preoperative chemotherapy

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Background: Neoadjuvant chemotherapy is now the standard of care of patients with resectable gastric carcinomas (GC). Predictive molecular markers and histopathological evidence of tumour response to chemotherapy are not widely available. In this study we evaluated HER2 status and histopathological features associated with tumor regression in 36 GC treated with neoadjuvant chemotherapy followed by surgery.

Methods: 36 patients had received ECF, DCF or ECX chemotherapy prior the surgery. The entire tumor beds of the specimens were histologically evaluated. HER2 expression by immunohistochemistry was detected in the biopsy and gastrectomy specimens.

Results: 46% of the cases were intestinal type, 40% were diffuse and 14% were unclassified. Nine patients had major clinical and radiological response (CRR) characterized by presence of viable tumor cells less than 50% of the tumor with increased fibrosis (>50%). Three cases had complete CRR showing tumor beds totally replaced by fibrosis. The remaining cases had minimal CRR characterized by viable tumor cells in more than 50% and minimal fibrosis. Necrosis was not found; mucinous metaplasia was observed in three cases of the major CRR. Inflammatory infiltrated was found in all cases. The downstaging of T-stage seems to be greater in the intestinal type than diffuse type (80% vs 44%). HER2+ (score 3) was detected in 16,6% of the biopsy specimen. Only 1 case was HER2+ in the biopsy and in the gastrectomy tissue. All the HER2+ GC showed minimal CRR.

Conclusions: The ratio of viable tumor cells and fibrosis is directly associated with tumor response to preoperative chemotherapy. The chemotherapy regimens seem to collaborate to downstaging rates; however the treatment of HER2+ GC group could be improved by the use of Ttrastuzumab.

Ileal loop interposition: an alternative biliary bypass technique

BACKGROUND

Obstructive jaundice is a common condition in advanced digestive cancer. Palliative procedures can improve quality of life and allow patients to attempt a systemic treatment. Bilioenteric anastomosis is still the procedure of choice for patients in many centers. When a surgical bypass is not possible, biliary drainage can be done by placing endoscopic or transparietal stents, which are less durable methods even when an expandable stent is employed.

METHODS

A 47-year-old male with an excellent clinical status and a previous cholecystectomy and an exploratory laparotomy for advanced gastric cancer was referred with obstructive jaundice. A preoperative CT scan showed a dilated bile duct and a small mass at the distal hepatic hilum. No other signs of metastasis were found. A surgical bilioenteric anastomosis was indicated. At surgery, a distal choledochal obstruction and a mesenteric retraction by a lymph node mass prevented the jejunum to ascend for a bilioenteric anastomosis. Surgically, an alternative bilioenteric bypass was performed by means of an ileal loop interposition between the bile duct and the jejunum.

RESULT

The recovery of the patient was uneventful and his bilirubin levels normalized after one week. The patient was then referred for systemic chemotherapy.

CONCLUSIONS

This alternative biliary bypass can be safely and easily performed, and may be a good alternative for patients already referred for surgery because of a better life expectancy and when the jejunum is not an alternative.

The interaction between N-category and N-ratio as a new tool to improve lymph node metastasis staging in gastric cancer: results of a single cancer center in Brazil

BACKGROUND

Depth of tumor invasion (T-category) and the number of metastatic lymph nodes (N-category) are the most important prognostic factors in patients with gastric cancer. Recently, the ratio between metastatic and dissected lymph nodes (N-ratio) has been established as one. The aim of this study is to evaluate the impact of N-ratio and its interaction with N-category as a prognostic factor in gastric cancer.

METHODS

This was a retrospective study in which we reviewed clinical and pathological data of 165 patients who had undergone curative surgery at our institution through a 9-year period. The exclusion criteria included metastases, gastric stump tumors and gastrectomy with less than 15 lymph nodes dissected.

RESULTS

The median age of the patients was 63 years and most of them were male. Total gastrectomy was the most common procedure and 92.1% of the patients had a D2-lymphadenectomy. Their 5-year overall survival was 57.7%. T-category, N-category, extended gastrectomy, and N-ratio were prognostic factors in overall and disease-free survival in accordance with univariate analysis. In accordance with TNM staging, N1 patients who have had NR1 had 5-year survival in 75.5% whereas in the NR2 group only 33% of the cases had 5-year survival. In the multivariate analysis, the interaction between N-category and N-ratio was an independent prognostic factor.

CONCLUSION

Our findings confirmed the role of N-ratio as prognostic factor of survival in patients with gastric cancer surgically treated with at least 15 lymph nodes dissected. The relationship between N-category and N-ratio is a better predictor than lymph node metastasis staging.

[Biology of Amazonian Anopheles. XII. Occurrence of Anopheles species, transmission dynamics and malaria control in the urban area of Ariquemes (Rondônia)]

Dados sobre o grau de incidência e distribuição de espécies Anopheles, em Ariquemes (RO), evidenciaram que a diversidade é maior na periferia da cidade e que Anopheles darlingi é registrada em praticamente todas as localidades de coleta. O inquérito entomológico revelou níveis diferentes de penetração da espécie na área urbana, podendo-se constatar que os Setores 1 e 3 são áreas livres de malária; Setores 2 e 4 mostram riscos na periferia; e a Área Industrial e Setor de Áreas Especiais, Conjunto BNH, Setor 5 e Vila Velha constituem áreas de alto risco da malária. Nestes últimos, os índices de mosquitos por homem/hora foram os mais elevados, observando-se variações no decorrer das amostragens e conforme a localização da área urbana. Medidas de densidade populacional revelaram mudanças estacionais, sendo os menores valores registrados no período de inverno. A transmissão da malária é discutida, considerando-se: 1) o papel da estrutura física da cidade, na época da fundação, 2) os igarapés que margeam a área urbana e suas relações com o ciclo de desenvolvimento dos anofelinos, 3) os padrões comportamentais da atividade de picar das espécies correlacionados a ambientes naturais e às áreas ecologicamente alteradas, e 4) a importância do manuseio ambiental no controle da malária, para redução da densidade populacional. Para conter o processo migratório do vetor é proposto um cinturão de proteção à cidade, constituído de mata não densa, incluindo também proteção biológica para incentivar a zoofilia dos anofelinos. Os resultados de infecção natural, obtidos em áreas de autoctonia da malária, permitem citar A. darlingi como vetor, sendo discutida a possibilidade de que outras espécies estejam envolvidas na transmissão.