Diagnosis Shift in Site of Origin of Tubo-Ovarian Carcinoma.

OBJECTIVE: To assess population-level trends, characteristics, and outcomes of high-grade serous tubo-ovarian carcinoma in the United States.

METHODS: This retrospective cohort study queried the National Cancer Institute's Surveillance, Epidemiology, and End Results Program. The study population was 27,811 patients diagnosed with high-grade serous tubo-ovarian carcinoma from 2004 to 2020. The exposure was the primary cancer site (ovary or fallopian tube). Main outcome measures were temporal trends, clinical characteristics, and overall survival associated with primary cancer site assessed in multivariable analysis.

RESULTS: The study population comprised 23,967 diagnoses of high-grade serous ovarian carcinoma and 3,844 diagnoses of high-grade serous fallopian tubal carcinoma. The proportion of diagnoses of high-grade serous fallopian tubal carcinoma increased from 365 of 7,305 (5.0%) in 2004-2008 to 1,742 of 6,663 (26.1%) in 2017-2020. This increase was independent in a multivariable analysis (adjusted odds ratio [aOR] vs 2004-2008, 2.28 [95% CI, 1.98-2.62], 3.27 [95% CI, 2.86-3.74], and 6.65 [95% CI, 5.84-7.57] for 2009-2012, 2013-2016, and 2017-2020, respectively). This increase in high-grade serous fallopian tubal carcinoma was seen across age groups (4.3-5.8% to 22.7-28.3%) and across racial and ethnic groups (4.1-6.0% to 21.9-27.5%) (all P for trend <.001). Among the cases of tumors smaller than 1.5 cm, the increase was particularly high (16.9-67.6%, P for trend <.001). Primary-site tumors in the high-grade serous fallopian tubal carcinoma group were more likely to be smaller than 1.5 cm (aOR 8.26, 95% CI, 7.35-9.28) and unilateral (aOR 7.22, 95% CI, 6.54-7.96) compared with those in high-grade serous ovarian carcinoma. At the cohort level, the diagnosis shift to high-grade serous fallopian tubal carcinoma was associated with narrowing differences in survival over time between the two malignancy groups: adjusted hazard ratio 0.84 (95% CI, 0.74-0.96), 0.91 (95% CI, 0.82-1.01), 1.01 (95% CI, 0.92-1.12), and 1.12 (95% CI, 0.98-1.29) for 2004-2008, 2009-2012, 2013-2016, and 2017-2020, respectively.

CONCLUSION: This population-based assessment suggests that diagnoses of high-grade serous tubo-ovarian carcinoma in the United States have been rapidly shifting from high-grade serous ovarian to fallopian tubal carcinoma in recent years, particularly in cases of smaller, unilateral tumors.