Low-grade Gliomas in Argentina: Incidence, Survival, and Therapeutic Strategies

Low-grade gliomas (LGG) are slow-growing primary brain tumors (WHO grades I-II), and their incidence, survival, and treatment patterns in middle-income settings such as Argentina remain poorly characterized. This retrospective, multicenter study comprises two complementary cohorts:

1. Cohort 1: The "captive" population covered under the Hospital Italiano de Buenos Aires Health Plan (January 2011-December 2023) to estimate LGG incidence density.
2. Cohort 2: Histologically confirmed LGG patients treated at the major referral centers to describe overall survival (OS) and disease-free survival (DFS) at 1 and 5 years.

Demographic, clinical, pathological, and treatment data will be collected in a centralized REDCap database.

The primary objective is to describe LGG incidence in Argentina and estimate survival using Kaplan-Meier curves. The secondary objectives include characterizing therapeutic strategies, molecular mutations, and prognostic factors through Cox regression analysis. This registry will fill a critical gap in LGG epidemiology in middle-income countries and generate hypotheses for future research.

Study Overview

• Status: Recruiting
• Conditions: Low-grade Glioma

Detailed Description

Background Low-grade gliomas (LGG) represent approximately 6% of primary central nervous system tumors in adults and exhibit unpredictable biological behavior. Although high-income countries have published LGG incidence and survival data stratified by age, sex, and molecular profile, data from Argentina and other middle-income regions are scarce. IDH mutations and other molecular markers, along with clinical factors (age, seizures, tumor volume, and location) and treatment modalities, influence disease progression and prognosis in these patients.

Objectives

• Primary (Cohort 1): Estimate LGG incidence density in the Hospital Italiano Health Plan population (2011-2023), expressed as cases per 100,000 person-years.
• Primary (Cohort 2): Describe OS and DFS at 1 and 5 years post-diagnosis.
• Secondary: Characterize therapeutic strategies (surgical, chemoradiotherapy, monotherapy), molecular profile (IDH, P53, 1p/19q mutations), and identify prognostic factors associated with OS and DFS using multivariable Cox regression.

Design and Scope

This is a retrospective, multicenter, observational cohort study with two cohorts:

• Cohort 1 (incidence): Retrospective analysis of the Hospital Italiano de Buenos Aires database to identify new LGG cases from January 2011 to December 2023.
• Cohort 2 (survival): Consecutive inclusion of all patients with histologically confirmed LGG treated at the participating centers during the same period.

Population

• Inclusion (Cohort 1): Age ≥ 18 years, HIBA affiliates, ≥ 1 year of documented follow-up.
• Inclusion (Cohort 2): Age ≥ 18 years, histologically confirmed LGG (WHO I-II), ≥ 1 year of documented follow-up.
• Exclusion (both cohorts): Incomplete or uncertain diagnosis per histopathological/genetic criteria.

Data Collection & Management Local investigators will extract demographic, clinical, radiological, pathological, and treatment data from electronic health records. All data will be entered retrospectively into a secure, centralized REDCap database with individual user credentials. Quality control checks (cross-validation with source records) will be performed periodically. After analysis and publication, the database will be permanently deleted to preserve confidentiality.

Key Variables

• Demographics: age, sex, comorbidities, functional status, care setting.
• Tumor Characteristics: volume, location (supra-/infratentorial, hemisphere), histology, IDH/P53 mutation status.
• Treatment Details: extent of resection (total/partial), chemotherapy (agents, cycles, toxicities), radiotherapy (type, dose, fractions).
• Outcomes: time to progression, OS, DFS, postoperative complications, adverse events.

Statistical Analysis

• Cohort 1: Calculate incidence density (cases/person-years) with 95 % confidence intervals by age and sex. Standardization will use INDEC population data.
• Cohort 2: Estimate OS and DFS at 1, and 5 years using Kaplan-Meier methods; report proportions with 95 % CIs. Perform multivariable Cox regression to identify prognostic factors (age, tumor volume, mutation status, treatment type), reporting hazard ratios with 95 % CIs.
• Sample Size: Approximately 180 000 person-years in Cohort 1 (projected 13-14 LGG cases); ≥ 40 patients in Cohort 2 to estimate a 30 % survival rate with ± 10 % precision.

Ethical Considerations The study has a waiver of informed consent under local regulations and CIOMS guidelines. All data will be anonymized using numeric codes and stored on encrypted servers until study completion. In addition, each participating center must obtain approval from its respective ethics committee (IRB/EC) before initiating data collection and provide documentation of such approvals.

• Study Type: Observational
• Enrollment (Estimated): 40

Contacts and Locations

• Study Contact: Name: Ivan Alfredo Huespe, MD, MPh; Phone Number: +5493425382554; Email: ivan.huespe@hospitalitaliano.org.ar
• Study Contact Backup: Name: Veronica Ester Monzon, MD; Phone Number: +5491165846854; Email: veronica.monzon@hospitalitaliano.org.ar

Study Locations

• Argentina
  • Buenos Aires F.D.
    • Buenos Aires, Buenos Aires F.D., Argentina, C1118AAT
      • Recruiting
      • Hospital Aleman
      • Contact: Daniel Ignacio Ivulich, MD; Phone Number: +5491161859413; Email: di.ivulich@gmail.com
    • Buenos Aires, Buenos Aires F.D., Argentina, C1199ABB
      • Recruiting
      • Hospital Italiano de Buenos Aires
      • Contact: Ivan Alfredo Huespe, MD, MPh; Phone Number: +5493425382554; Email: ivan.huespe@hospitalitaliano.org.ar
  • Córdoba Province
    • Córdoba, Córdoba Province, Argentina, X5016KEH
      • Recruiting
      • Hospital Privado Universitario De Cordoba
      • Contact: Emiliano Tornu, MD; Phone Number: +5491164073575; Email: emilianocornu@gmail.com
  • Florencio Varela
    • Buenos Aires, Florencio Varela, Argentina, B1888
      • Recruiting
      • Hospital de Alta Complejidad El Cruce - Dr. Néstor Kirchner
      • Contact: Maximiliano Núñez, MD; Phone Number: +5492216061422; Email: maxineuro@gmail.com
  • Pilar
    • Buenos Aires, Pilar, Argentina, B1629AHJ
      • Recruiting
      • Hospital Universitario Austral
      • Contact: Alicia Gira, MD; Phone Number: +5491126336442; Email: aliciaroxanagira@gmail.com
  • San Justo
    • Buenos Aires, San Justo, Argentina, C1198AAW
      • Recruiting
      • Hospital Italiano sede San Justo Agustín Rocca
      • Contact: Veronica Ester Monzon, MD; Phone Number: +5491165846854; Email: veronica.monzon@hospitalitaliano.org.ar

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Adult (≥18 years) Hospital Italiano Health Plan affiliates (Cohort 1) and histologically confirmed WHO grade I-II low-grade glioma patients treated at participating centers (Cohort 2), retrospectively identified for incidence and survival analyses.

Description

Study population cohort 1

• Inclusion Criteria

  • Adult patients (≥18 years old) affiliated to the health plan of Hospital Italiano de Buenos Aires.
  • Documented clinical follow-up of at least 1 year during the study period.

• Exclusion Criteria

  • Patients not affiliated to the health plan of the Hospital Italiano de Buenos Aires.

Study population cohort 2

• Inclusion Criteria

  • Adult patients (≥18 years) with histopathologically confirmed diagnosis of low-grade glioma (WHO grades I and II).

• Exclusion Criteria

  • Incomplete or doubtful diagnosis based on histopathologic and molecular criteria.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Cohort 1: Incidence cohort; Affiliates of the Hospital Italiano Health Plan from January 2011 to December 2023 used to estimate the incidence density of low-grade gliomas.
Cohort 2: Survival cohort; Histologically confirmed low-grade glioma patients treated at participating centers, followed retrospectively for up to 5 years to assess overall and disease-free survival.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Describe the incidence density of LGG	The incidence density will be estimated as the number of new cases of LGG divided by the person-time at risk (expressed in patient-years). The incidence stratified by age group, and sex, with corresponding 95% confidence intervals, will be described.	January 2011 - December 2023
Generate an Argentine population projection model	A model will be developed to extrapolate the incidence rates of LGG calculated in the HIBA cohort to the general Argentine population. Initially, specific incidence rates will be estimated, both overall and stratified by age and sex, including 95% confidence intervals to ensure accuracy. Subsequently, a standardization process will be applied to adjust for demographic differences between the HIBA population and the general population of Argentina, using data from the National Institute of Statistics and Census of Argentina (In Spanish: Instituto Nacional de Estadísticas y Censos [INDEC]). Finally, the expected cases of LGG will be extrapolated to the national level, generating specific estimates by age and sex per year.	January 2011 - December 2023
Describe overall survival (OS) and disease-free survival (DFS)	OS and DFS will be estimated using life tables and plotted with Kaplan-Meier graphs. Survival and disease-free survival at 1 and 5 years will be reported with the corresponding proportion and 95% confidence interval.	Up to 5 years post-diagnosis
Describe the treatment strategies implemented in patients with LGG in public and private institutions	Absolute and relative frequencies will be calculated for the treatment strategies used (surgical treatment, chemo-radiotherapy, radiotherapy alone), stratified by type of institution (public or private). Proportions will be reported with their corresponding 95% confidence interval.	January 2011 - December 2023

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Evaluate factors associated with shorter time to death or death and relapse	Cox regression models will be used to identify factors associated with shorter time to death and time to death or relapse. Independent variables such as age, comorbidities, tumor location and volume, molecular status (HDI, 1p/19q codeletion), and type of treatment received will be included. Results will be reported as Hazard Ratio with 95% confidence intervals. Data will be plotted with Kaplan-Meier curves.	Up to 5 years post-diagnosis

Collaborators and Investigators

• Sponsor: Hospital Italiano de Buenos Aires
• Investigators: Study Director: Ivan Alfredo Huespe, MD, MPh, Hospital Italiano de Buenos Aires

Study record dates

Study Major Dates

• Study Start (Actual): April 1, 2026
• Primary Completion (Estimated): February 1, 2027
• Study Completion (Estimated): May 31, 2027

Study Registration Dates

• First Submitted: June 1, 2026
• First Submitted That Met QC Criteria: June 1, 2026
• First Posted (Actual): June 8, 2026

Study Record Updates

• Last Update Posted (Actual): June 8, 2026
• Last Update Submitted That Met QC Criteria: June 1, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: Survival; Glioma; Brain tumor; Incidence; Neuro-oncology; Low-grade glioma
• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Neoplasms by Site; Neoplasms; Neoplasms by Histologic Type; Neoplasms, Glandular and Epithelial; Neoplasms, Neuroepithelial; Neuroectodermal Tumors; Neoplasms, Germ Cell and Embryonal; Neoplasms, Nerve Tissue; Nervous System Neoplasms; Central Nervous System Neoplasms; Glioma; Brain Neoplasms
• Other Study ID Numbers: 7339

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: The study team is currently evaluating the feasibility of sharing de-identified individual participant data, taking into account ethical approvals, data privacy regulations, and the resources required for proper anonymization and curation. A final plan will be determined after completion of data collection and primary analyses.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No