Impact of year-end holidays on delayed cancer diagnoses and survival implications: A population-based study.

e13793 Background: Timely diagnosis and treatment initiation are critical for optimizing cancer survival outcomes. However, periods of reduced healthcare accessibility and shifts in patients' routines, such as during holidays, may contribute to delays. This study aims to assess whether end-of-year holiday schedules influence the timing of cancer diagnoses and impact care until the start of the new year. Methods: The NPCR-SEER database, representing almost the entire U.S. population, was utilized to analyze the month of a cancer diagnosis, merged summary stage at diagnosis, and trends over the study period. The SEER Research Plus 22 registries dataset was used to compare survival outcomes between months of diagnosis. Results: Between 2001 and 2020, a total of 31,845,368 cancer diagnoses were reported. By month, January had the highest number of diagnoses (n = 2,824,204) while December had the lowest (n = 2,483,880) (Table 1). When stratified by stage, January had the highest proportion of distant stage cancers at 24.48% (n = 691,296) and the lowest proportions of in-situ stage 1.80% (n = 50,813), localized stage 42.66% (n = 1,204,755) and regional stage 19.65% (n = 555,000) compared to all other months. Over the years, cancer cases increased for both months, but the disparity between them remained. For instance, in December 2019 there were 34,064 distant-stage diagnoses (21,611 in 2001), while in January 2020, there were 39,501 diagnoses (27,810 in 2001). When 5-year overall observed survival was compared, cases diagnosed in January were found to have the worst survival 59.10% (95% Confidence Interval (CI): 59.00 – 59.20) compared to cancers diagnosed in any other month. The month of October had comparatively the highest proportion of localized stage 44.56% (n = 1,230,826) and the best 5-year survival of 60.3% (95% CI: 60.1 – 60.4). Conclusions: Throughout the year, the highest number of cancer diagnoses occur in January, while the fewest occur in December. These New Year cancer patients had a higher burden of advanced disease and comparatively worse 5-year survival when compared to patients diagnosed during other months. Further research is necessary to determine whether the observed disparities are attributable to patient preference, healthcare accessibility during end-of-year holidays, payor factors, or other variables. Distribution of reported cases diagnosed by month from 2001 – 2020. Month Reported Cases (%) Month Reported Cases (%) January 2,824,204 (8.87) July 2,612,396 (8.20) February 2,495,900 (7.84) August 2,698,061 (8.47) March 2,702,753 (8.49) September 2,558,890 (8.04) April 2,607,534 (8.19) October 2,743,718 (8.62) May 2,659,799 (8.35) November 2,507,150 (7.87) June 2,739,798 (8.60) December 2,483,880 (7.80)