Measurement of tumor volume by PET to evaluate prognosis in patients with advanced cervical cancer treated by radiation therapy

Purpose: This study evaluated the usefulness of tumor volume measurement with positron emission tomography (PET) in patients with advanced cervical cancer treated by radiation therapy. Methods and Materials: Fifty-one patients underwent PET before treatment. Primary tumor volume was determined, and volume, FIGO stage, and presence of lymph nodes on the PET study were compared to progression-free survival (PFS) and overall survival (OS). Results: Tumor volume, lymph node disease, and stage were predictive of PFS, whereas volume and lymph node involvement predicted OS. Lymph node status did not correlate with volume. Dividing patients according to whether the tumor volume was more or less than 60 cm³ predicted PFS and OS. Separation of patients with tumor volumes ≤60 cm³ and no lymph node disease vs. any other combination was strongly predictive of PFS and OS. Conclusions: The following conclusions were drawn regarding patients with advanced cervical cancer treated with radiation therapy: (1) Tumor volume can be accurately measured by PET; (2) Tumor volume separates patients with a good prognosis from those with a poorer prognosis; (3) A subset of patients with relatively small tumors and no lymph node involvement does remarkably well; (4) Tumor volume does not correlate with the presence of lymph node disease.