Clinical and Dosimetric Results of Proton or Photon Radiotherapy for Large >5 cm Hepatocellular Carcinoma

A Retrospective Analysis

When dealing with large, inoperable liver tumors (specifically hepatocellular carcinoma, or HCC), choosing the right type of radiation therapy can make a significant difference in patient outcomes. In a recent study published in The Red Journal, researchers aimed to understand the clinical and dosimetric differences between proton therapy and traditional photon therapy in treating such conditions.

The study focused on 159 patients with non-metastatic HCC tumors larger than 5 cm. These patients received definitive radiation treatment between 2014 and 2018, with 105 treated using proton radiation and 54 using photon radiation. Researchers also compared additional photon plans for the proton-treated patients to measure dosimetric (dose distribution within the body) differences.

What the Data Tells Us…

After following these patients for an average of 47 months, the results clearly favored proton therapy:

Better Disease Control and Survival Rates: Patients receiving a higher dose, measured in biologically effective dose (BED10) of at least 75 Gray (Gy), showed significantly better outcomes. 

This group had:

  • A two-year local control rate (chance the cancer doesn’t grow back in the same place) of 85.6% compared to only 20.5% in those receiving lower doses.
  • Median progression-free survival (time during and after treatment that a patient lives without the cancer worsening) of 7.4 months versus 3.2 months.
  • Median overall survival (time from treatment until death from any cause) of 18.1 months compared to 7.3 months.

Proton vs. Photon Therapy: Proton therapy not only allowed for higher effective doses but also resulted in:

  • Significantly better control of the local tumor.
  • Longer progression-free and overall survival times.
  • Lower doses to surrounding organs, resulting in fewer serious side effects such as liver disease and gastrointestinal bleeding.

Less Radiation to Healthy Tissues

A notable advantage of proton therapy is its precision, which minimizes radiation exposure to healthy tissues. The study showed:

  • Significantly lower radiation doses to the liver, upper gastrointestinal tract, and spleen in proton-treated patients.
  • Reduced instances of severe side effects like liver disease, gastrointestinal bleeding, and significant decreases in white blood cell count (lymphopenia).

The findings from this study underscore the potential of proton therapy in treating large liver cancers more effectively and safely than traditional photon therapy. By delivering higher, more targeted doses of radiation, proton therapy improves the control of the disease, extends survival, and reduces harmful side effects.

This study is a promising step forward in oncology, providing compelling evidence for the benefits of advanced proton therapy in complex cancer cases. For patients battling large hepatocellular carcinoma, these insights could mean a higher chance of managing the disease with better quality of life outcomes.

Read full study here.

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