Does ovarian cancer survival differ by who gives the chemotherapy?

Abstract

6110 Background: Medical Oncologists (MOs) specialize in administering chemotherapy while Gynecologic Oncologists (GOs) specialize in the surgical management of gynecologic cancers as well as providing chemotherapy. We asked whether survival differed according to the type of specialist providing the chemotherapy after ovarian cancer surgery. Methods: Using merged SEER-Medicare clinical and administrative data from the years 1991 through 2001 we identified all patients who were diagnosed with ovarian cancer after the age of 65 and who received chemotherapy from a GO after surgery performed by any type of surgeon. Using optimal matching and a propensity score based on 35 prognostic characteristics, we identified similar patients who were operated on, and staged, by nearly identical types of surgeons but who received chemotherapy from an MO. Results: We identified 344 patients who were given chemotherapy for ovarian cancer by GOs after having undergone surgery by either GOs (76%), Gynecologists (16%), or general surgeons or other surgical specialties (8%). Patients given chemotherapy by MOs were matched to these patients. Both groups had nearly identical surgical specialists, age, year of treatment, stage, tumor grade, race and 32 other prognostic factors. There was no difference in overall survival between the GO or MO groups (P = 0.45, paired Prentice-Wilcoxon test). The 5 year survival was 35% (± 2.6%) for the GO group and 34% (± 2.6%) for the MO group. However, MOs administered chemotherapy over more weeks than did the GOs (patient mean = 16.5 Vs 12.1 weeks, P < 0.0023, Wilcoxon rank sum test) and MO patients had more weeks that included at least one of the following chemotherapy associated adverse events (neutropenia, anemia, thrombocytopenia, diarrhea, dehydration or mucositis) than did the GO group (patient mean = 16.2 Vs 8.9 weeks, P < 0.0001, Wilcoxon rank sum test). Conclusions: Despite differences in training, specialty emphasis, and practice style concerning the use of chemotherapy (MO patients had more weeks of chemotherapy and more weeks with chemotherapy associated adverse events than GO patients), we found no difference in survival between patients who received chemotherapy administered by gynecologic oncologists and medical oncologists. No significant financial relationships to disclose.