Association between Overall Survival and the Tendency for Cancer Programs to Administer Neoadjuvant Chemotherapy for Patients with Advanced Ovarian Cancer

Importance: Randomized clinical trials have found that, in patients with advanced-stage epithelial ovarian cancer, neoadjuvant chemotherapy has similar long-term survival and improved perioperative outcomes compared with primary cytoreductive surgery. Despite this, considerable controversy remains about the appropriate use of neoadjuvant chemotherapy, and the proportion of patients who receive this treatment varies considerably among cancer programs in the US. Objective: To evaluate the association between high levels of neoadjuvant chemotherapy administration and overall survival in patients with advanced ovarian cancer. Design, Setting, and Participants: This difference-in-differences comparative effectiveness analysis leveraged differential adoption of neoadjuvant chemotherapy in Commission on Cancer-accredited cancer programs in the US and included women with a diagnosis of stage IIIC and IV epithelial ovarian cancer between January 2004 and December 2015 who were followed up through the end of 2018. The data were analyzed between September 2020 and January 2021. Exposures: Treatment in a cancer program with high levels of neoadjuvant chemotherapy administration (more often than expected based on case mix) or in a program that continued to restrict its use after the 2010 publication of a clinical trial demonstrating the noninferiority of neoadjuvant chemotherapy compared with primary surgery for the treatment of patients with advanced ovarian cancer. Main Outcomes and Measures: Case mix-standardized median overall survival time and 1-year all-cause mortality assessed with a flexible parametric survival model. Results: We identified 19562 patients (mean [SD] age, 63.9 [12.6] years; 3.2% Asian, 8.0% Black, 4.8% Hispanic, 82.5% White individuals) who were treated in 332 cancer programs that increased use of neoadjuvant chemotherapy from 21.7% in 2004 to 2009 to 42.2% in 2010 to 2015 and 19737 patients (mean [SD] age, 63.5 [12.6] years; 3.1% Asian, 7.7% Black, 6.5% Hispanic, 81.8% White individuals) who were treated in 332 programs that marginally increased use of neoadjuvant chemotherapy (20.1% to 22.5%) over these periods. The standardized median overall survival times improved by similar magnitudes in programs with high (from 31.6 [IQR, 12.3-70.1] to 37.9 [IQR, 17.0-84.9] months; 6.3-month difference; 95% CI, 4.2-8.3) and low (from 31.4 [IQR, 12.1-67.2] to 36.8 [IQR, 15.0-80.3] months; 5.4-month difference, 95% CI, 3.5-7.3) use of neoadjuvant chemotherapy after 2010 (difference-in-differences, 0.9 months; 95% CI, -1.9 to 3.7). One-year mortality declined more in programs with high (from 25.6% to 19.3%; risk difference, -5.2%; 95% CI, -6.4 to -4.1) than with low (from 24.9% to 21.8%; risk difference, -3.2%, 95% CI, -4.3 to -2.0) use of neoadjuvant chemotherapy (difference-in-differences, -2.1%; 95% CI, -3.7 to -0.5). Conclusions and Relevance: In this comparative effectiveness research study, compared with cancer programs with low use of neoadjuvant chemotherapy, those with high use had similar improvements in median overall survival and larger declines in short-term mortality.