Predicting the probability of progression-free survival in patients with small hepatocellular carcinoma

Authors

  • Steve J. Cheng,

    1. Department of Medicine, Division of Clinical Decision Making, New England Medical Center, Tufts University School of Medicine, Boston, MA
    2. Department of Medicine, Division of Gastroenterology, New England Medical Center, Tufts University School of Medicine, Boston, MA
    Search for more papers by this author
  • Richard B. Freeman Jr,

    1. Department of Surgery, Division of Transplantation, New England Medical Center, Tufts University School of Medicine, Boston, MA
    Search for more papers by this author
  • John B. Wong MD

    Corresponding author
    1. Department of Medicine, Division of Clinical Decision Making, New England Medical Center, Tufts University School of Medicine, Boston, MA
    • New England Medical Center, 750 Washington St, Box 302, Boston, MA 02111. Telephone: 617-636-5695; Fax: 617-636-4838
    Search for more papers by this author

Abstract

Allocation of cadaveric livers to patients based on such objective medical urgency data as the Model for End-Stage Liver Disease (MELD) score may not benefit patients with small hepatocellular carcinomas (HCCs). To ensure that these patients have a fair opportunity of receiving a cadaveric organ, the risk for death caused by HCC and tumor progression beyond 5 cm should be considered. Using a Markov model, two hypothetical cohorts of patients with small hepatomas were assumed to have either (1) Gompertzian tumor growth, in which initial exponential growth decreases as tumor size increases; or (2) rapid exponential growth. The model tracked the number of patients who either died or had tumor progression beyond 5 cm. These results were used to back-calculate an equivalent MELD score for patients with small HCCs. All probabilities in the model were varied simultaneously using a Monte Carlo simulation. The Gompertzian growth model predicted that patients with a 1- and 4-cm tumor have 1-year progression-free survival rates of 70% (HCC-specific MELD score 6) and 66% (HCC-specific MELD score 8), respectively. When assuming rapid exponential growth, patients with a 1- and 4-cm tumor have progression-free survival rates of 69% (HCC-specific MELD score 6) and 12% (HCC-specific MELD score 24), respectively. Our model predicted that the risk for death caused by HCC or tumor progression beyond 5 cm should increase with larger initial tumor size in patients with small hepatomas. To ensure that these patients have a fair opportunity to receive a cadaveric organ, HCC-specific scores predicted by our model could be added to MELD scores of patients with HCC.

Ancillary