Real-world associations among patient-physician sex concordance, treatment practices, and cancer outcomes.

Abstract

e18511 Background: Prior research has linked patient-physician sex discordance with inferior surgical and cardiac outcomes. The impact of such sex inequities may be magnified in medical oncology, where patients often face a life-limiting illness and physicians assume the role of primary healthcare provider. This study examined cancer treatment practices and survival outcomes in sex-concordant vs. discordant patient-physician dyads. Methods: This was a population-based, retrospective cohort study of adults diagnosed with stage II-IV colon or lung cancer in 2013-2020 in Alberta, Canada and referred to a medical oncologist. Study data included physician- and patient-level demographics and cancer disease characteristics. Patient-physician dyads were classified as sex-concordant (female-female, male-male) or discordant (female-male, male-female). Time-to-event data were analysed using Kaplan-Meier methods and associations were assessed with Cox and logistic regression. Results: A total of 11,131 patients and 188 medical oncologists were included. Among patients, 49% were female and 50% were in sex-concordant patient-physician dyads. The median age was 68 years, 7615 (68%) had lung cancer, and 6016 (54%) had stage IV disease. In sex-concordant and discordant dyads, respectively, median overall survival (OS) was 17.1 and 18.7 months ( p = 0.047) while median cancer-specific survival (CSS) was 20.2 and 22.4 months ( p = 0.21). In multivariable analysis, sex-concordance was not significantly associated with OS or CSS in the overall cohort and in female patients. However, among male patients, sex-discordance was significantly associated with lower OS (hazard ratio [HR], 1.11; 95% CI, 1.04-1.19) and CSS (HR, 1.12; 95% CI 1.04 -1.21), largely driven by differences in survival outcomes in stage IV disease. Older age, higher comorbidity burden, lung cancer, and advanced stage correlated with worse outcomes in all multivariable models. Sex concordance was not significantly associated with adjuvant systemic anti-cancer therapy (SACT) use in stage II-III disease or with SACT use in stage IV disease. Treatment practices are summarized in the table. Conclusions: Sex concordance between patients and medical oncologists did not generally correlate with differential SACT use and survival. However, male patients treated by female physicians had worse outcomes compared to those treated by male physicians. Cancer outcomes may be prone to the effects of sex bias in specific patient-physician relationships. [Table: see text]