External validation and calibration of the HoLISTIC Consortium's advanced-stage Hodgkin lymphoma international prognostic index (A-HIPI) in the Brazilian Hodgkin lymphoma registry.

in British journal of haematology by Valeria Buccheri, Frederico Rafael Moreira, Irene Biasoli, Nelson Castro, Carolina Colaço Villarim, Fabiola Traina, Talita Silveira, Monica Kopschitz Praxedes, Cristiana Solza, Leila Perobelli, Otavio Baiocchi, Rafael Gaiolla, Carla Boquimpani, Caroline Bonamin Sola, Roberta Oliveira de Paulae Silva, Ana Carolina Ribas, Kátia Pagnano, Giovanna Steffenello, Carmino de Souza, Nelson Spector, Angie Mae Rodday, Andrew M Evens, Susan K Parsons,

TLDR

  • This study validated the A-HIPI model's performance in predicting survival outcomes in advanced-stage cHL patients in the Brazilian cohort, demonstrating its reliability in diverse settings.

Abstract

The Hodgkin lymphoma International Study for Individual Care (HoLISTIC) Consortium's A-HIPI model, developed in 2022 for advanced-stage classical Hodgkin lymphoma (cHL), predicts survival within 5 years amongst newly diagnosed patients. This study validates its performance in the Brazilian Hodgkin lymphoma registry. By 2022, the Brazilian HL registry included 1357 cHL patients, with a median 5-year follow-up. Probabilities for 5-year progression-free survival (PFS) and overall survival (OS) were calculated using A-HIPI-model equations. Discrimination (Harrell C-statistic/Uno C-statistic) and calibration measures assessed external validation and calibration. Lab values beyond the allowed range were excluded, mirroring the initial A-HIPI analysis. A total of 694 advanced-stage cHL patients met the original inclusion criteria (age 18-65 years, Stage IIB-IV). Median age was 31 years; 46.3% were females. Stage distribution was IIB (33.1%), III (27.4%), IV (39.5%). Bulky disease in 32.6%. Five-year PFS and OS were 68.4% and 86.0%, respectively. Harrell C-statistics were 0.60 for PFS and 0.69 for OS, and Uno C-statistics were 0.63 for PFS and 0.72 for OS. Calibration plots demonstrated well-calibrated predictions with calibration slopes of 0.91 and 1.03 for 5-year OS and PFS, respectively. Despite differing patient, clinical characteristics, and socioeconomic factors, the baseline prediction tool performed well in the Brazilian cohort, demonstrating adequate discrimination and calibration. This supports its reliability in diverse settings.

Overview

  • The study aims to validate the performance of the A-HIPI model, a prediction tool for advanced-stage classical Hodgkin lymphoma (cHL), in the Brazilian Hodgkin lymphoma registry.
  • The study analyzed a cohort of 694 advanced-stage cHL patients with a median 5-year follow-up to calculate probabilities for 5-year progression-free survival (PFS) and overall survival (OS) using the A-HIPI-model equations.
  • The primary objective is to assess the external validation and calibration of the A-HIPI model in a Brazilian cohort with diverse patient, clinical, and socioeconomic factors.

Comparative Analysis & Findings

  • The study found that the A-HIPI model performed well in the Brazilian cohort, with Harrell C-statistics of 0.60 for PFS and 0.69 for OS, and Uno C-statistics of 0.63 for PFS and 0.72 for OS.
  • The calibration plots demonstrated well-calibrated predictions, with calibration slopes of 0.91 and 1.03 for 5-year OS and PFS, respectively.
  • Despite differences in patient, clinical, and socioeconomic characteristics, the baseline prediction tool showed adequate discrimination and calibration, supporting its reliability in diverse settings.

Implications and Future Directions

  • The study's findings support the reliability of the A-HIPI model in predicting survival outcomes in patients with advanced-stage cHL, regardless of the geographic location or patient characteristics.
  • Future studies should explore the A-HIPI model's performance in specific subpopulations, such as those with different stages, ages, or treatment regimens, to further refine its predictive capabilities.
  • The development of a global standardized system for monitoring and reporting cHL outcomes would facilitate international comparisons and improve patient care.
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