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Liddell, S.

https://orcid.org/0000-0002-4330-6363

Mayo Clinic

Mayo Clinic

Citations 9

Clinics and Clicks: Optimizing Hematology Care Delivery and Workflows in the Digital Era
Marar, Rosalyn, Liddell, S. , Toumeh, Nadia , Bentz, Caleb , Paulson, Damian, Stegemann, Hollie, Hogan, William J., Al‐Kali, Aref , Go, Ronald S. , Marar, Rosalyn , Liddell, Savannah S , Paludo, Jonas , Go, Ronald S , Godby, Richard Curtis , Paulson, Damian J., Hogan, William J. , Paludo, Jonas , Godby, Richard

JCO Oncology Practice | August 7, 2026 | Volume: No volume available | Issue: No issue available | Pages: No page available

10.1200/op-26-00392 Get It

PURPOSE Hematology care delivery is changing rapidly for patients, care teams, and health care institutions. This study simultaneously evaluated utilization data for synchronous/real-time patient appointments, asynchronous/time-delayed patient communications, and provider preferences in a large academic hematology practice to inform sustainable care delivery and workflows in the digital era. METHODS We conducted a retrospective analysis of aggregated adult hematology appointment and patient communication data at Mayo Clinic (Rochester, MN) from January 2023 to January 2025. Data were stratified by appointment modality, patient characteristics, and electronic health record (EHR) message volumes. Additionally, a voluntary, anonymous survey assessed hematology provider preferences regarding appointment modalities, in-basket burdens, and billing practices. RESULTS Among 83,713 completed appointments, 80.8% were in-person, 12.9% video, and 6.4% telephone. Patients age 80 years and older and rural cohorts used virtual modalities at rates comparable with younger and metropolitan cohorts. Asynchronous communication volume was considerable, with 155,036 patient-initiated telephone calls generating a digital cascade of 407,578 EHR messages (a 1:2.6 ratio) and 49,798 patient-initiated advice request in-basket messages generating 343,030 additional EHR messages (a 1:6.9 ratio). Providers (n = 53) strongly preferred in-person appointments for new consults (92.5%) and active therapy management (90.6%) but favored virtual appointments for surveillance (52.8%). Although 86.8% of providers reported spending >30 minutes daily on in-basket management, 94.3% reported not billing for this time. CONCLUSION Telehealth is a substantial component of modern hematology practice, used across all age groups. However, digital cascading and proliferation of asynchronous communications present an invisible and uncaptured workload. Optimizing care delivery could include implementation of a stratified hybrid model, prioritizing in-person appointments for high-acuity needs and virtual appointments for low-acuity needs, alongside standardized workflows to mitigate burdens of the digital era.
Assessing the Current Stage of Burnout in Hematology-Oncology Faculty and Trainees— Is There a Path to Remission?
Liddell, S. , Hendrickson, Andrea E. Wahner , Costello, Brian A. , Price, Katharine A. , Ruddy, Kathryn J. , Marshall, Ariela L. , O’Sullivan, Ciara C. , Liddell, Savannah S , O'Sullivan, Ciara C, Marshall, Ariela , Tevaarwerk, Amyé , Siontis, Brittany L. , Gergelis, Kimberly R. , West, Colin P.

Journal of the National Comprehensive Cancer Network | December 17, 2025 | Volume: 24 | Issue: 1 | Pages: No page available

10.6004/jnccn.2025.7087 Get It

Physician burnout is prevalent and contributes to the high number of physicians choosing to leave clinical practice. The field of hematology-oncology (HO) poses unique challenges for trainees and staff physicians who have to deliver bad news, manage complicated psychosocial situations, deal with the limited ability to prolong life, and juggle multiple time-sensitive demands from coworkers, patients, and families. Furthermore, they often face the death of their patients, along with its emotional toll on patients’ families and the physicians themselves. Burnout in HO is prevalent and increasing, with many physicians reporting in several studies that they plan to reduce working hours and/or retire early. The demand for hematologists and oncologists is rapidly rising, but in the setting of a worsening HO workforce shortage and an increasing number of patients with cancer. Therefore, it is imperative to develop strategies to mitigate or address burnout in HO physicians to improve well-being and prevent attrition. Herein, we describe risk factors and causes of physician burnout in HO trainees and practicing physicians in the United States, with a focus on institutional and individual strategies to address this issue. We also provide recommendations to address the burnout epidemic from the HO standpoint.
Clinics and clicks: Understanding hematology healthcare delivery utilization and preferences in the digital era
Marar, Rosalyn, Toumeh, Nadia , Liddell, S. , Bentz, Caleb C., Paulson, Damian, Stegemann, Hollie, Paulson, Damian, Paludo, Jonas , Go, Ronald S. , Godby, Richard

Blood | December 4, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 2864-2864

10.1182/blood-2025-2864 Get It

Abstract Background: The landscape of healthcare delivery in hematology has undergone significant transformations with the increasing adoption of telehealth services for appointments and communications in conjunction with the 2016 21st Century Cures Act providing patients complete access to their health information. Digital healthcare services in hematology offer benefits, including convenience and equitable access to those limited by travel or financial burdens. However, they also have inherent risks, including loss of in-person communication, disparities in access to technology, differences in digital literacy, and increased provider workload and burnout. Thus, we analyzed contemporary utilization patterns of hematology healthcare and provider preferences to optimize implementation of evolving hybrid care models. Methods: We analyzed data from the Mayo Clinic (Rochester, MN) Hematology Appointments Office and the Hematology Call Center as well as digital messaging practices using Epic's SlicerDicer tool. Data was collected between January 2023 and January 2025, during which patients had access to the electronic health record (EHR) and direct messaging capabilities. An optional survey was distributed to Hematology providers including physician consultants, fellows, and advanced practice providers (APP) to assess practice preferences. Results: During the analyzed period, a total of 85,899 hematology appointments were completed and captured all adult ages, including 18-34 (4.6%), 35-49 (9.2%), 50-64 (25.3%), 65-79 (48.3%), and 80+ (12.6%). Although in-person, video, and telephone visit options were available, in-person visits predominated across all age groups, with 80.6% of all completed appointments occurring in-person, 12.9% via video, and 6.5% via telephone. Notably, patients aged 80+ had the second highest combined use of video and telephone visits, with over 20% of their appointments conducted virtually. There was a total of 6,893 no-show and cancelled appointments, with 79.9% of these scheduled in-person, 14.8% via video, and 5.3% via telephone. There were over 4,000,000 portal messages in the hematology division with over 1,000,000 sent directly to hematology providers. Patients sent 105,284 new messages, of which 47.2% were new patient advice requests to providers which cascaded to 343,103 additional messages. Patients made 155,036 telephone calls, which cascaded to 407,578 messages over the portal, 78.5% of which were sent directly to providers. Notably, utilization of both portal messaging and telephone calls was similar across all age cohorts, including those 80+ years. Providers only initiated 14,159 new messages to patients yet sent a total of 354,172 messages. The hematology provider survey had a response rate of 42% (53 of 129). Respondents included 45.3% consultants, 45.3% fellows, and 9.4% APPs. 92.5% and 90.6% of providers preferred in-person appointments for new visits and established visits on therapy, respectively. In contrast, 52.8% preferred virtual appointments for established patients not currently receiving therapy. 73.6% and 52.8% of survey respondents either strongly agreed or agreed that virtual appointments are advantageous for patients and providers, respectively. Additionally, only 49.1% felt portal messages were necessary to provide high quality care and 64.2% preferred appointments over communicating through messages. 86.8% of providers reported spending more than 30 minutes daily responding to in-basket messages, however, 94.3% reported not routinely billing for their time. Conclusions: In the digital era, hematology healthcare delivery is multifaceted and increasingly demanding with high rates of patient engagement in their care via various mediums. To our knowledge, this is the largest analysis combining EHR utilization and appointment data with provider preferences to better understand digital hematology care. Digital appointments and communications were common amongst all age groups, including older patients, and had relatively low cancellations rates. Promotion of virtual visits to facilitate patient-provider conversations in addition to standardization of digital communication workflows are low-risk, high-yield interventions to mitigate the cascading of EHR-based communications, especially for those not actively receiving therapy. Together, these could decrease provider burnout while increasing healthcare system operational capacities to provide optimal patient care and satisfaction.
Navigating the cyber shift: The trends of electronic health record (EHR) engagement in oncology.
Liddell, S. , Orusa, Ahauve, Price, Katharine A. , Hendrickson, Andrea E. Wahner , O’Sullivan, Ciara C. , Ruddy, Kathryn J. , Godby, Richard , Giridhar, Karthik V. , Tevaarwerk, Amyé

Journal of Clinical Oncology | May 28, 2025 | Volume: 43 | Issue: 16_suppl | Pages: No page available

10.1200/jco.2025.43.16_suppl.e13718 Get It

e13718 Background: Oncology has evolved in the cyber era of medicine. The 21 st Century Cures Act mandated patient access to medical data (tests, provider notes) via patient portals connected to EHRs in order to facilitate patient engagement. Furthermore, the COVID-19 pandemic rapidly transformed patients’ interactions with portals by increasing reliance on telehealth and portal messaging. This shift has been well-documented in primary care, and emerging research suggests similar trends in oncology. More information is needed regarding how this has evolved post-pandemic. We present single academic institution real-world data (RWD) describing ongoing changes in patient messages and telephone calls in oncology. Methods: We quantified the changes (2019-2024) within oncology at Mayo Clinic Rochester campus including all care team, provider, nursing, and pharmacist visits, patient portal medical advice requests, patient calls, and messages sent to patients per year using Epic's SlicerDicer™ tool. Results: Patient visits/year dipped (-0.2%) from 2019 to 2020, but increased steadily from 2021 forward (Table 1). Patient portal advice requests increased significantly faster (Table 1); from 2019 to 2024, visits /year increased by 40%, while the number of advice requests increased by 131%. Patient calls/year increased more modestly (64%), while the number of messages sent to patients increased by 163% over this time. Conclusions: The transparency allowed by the Cures Act coupled with the impact of the pandemic has empowered patients to engage in their oncology care more proactively through the EHR. Patient-initiated portal messaging is increasing, with messages sent to patients from the oncology department similarly rising. Patient call volumes are also growing despite EHR messaging. Further research is necessary to better understand patterns of EHR use in oncology and explore ways to reduce clinician burnout that may arise from responding to this increased communication volume, as well as to understand the impact on patient satisfaction and outcomes. Changes in patient volume compared to patient calls and EHR messaging over time. Year Total Patient Visits Change in Patient Visits from Prior Year (%) Total Patient Medical Advice Messages Change in Patient Medical Advice Message Volume from Prior Year (%) Total Patient Calls Change in Patient Call Volume from Prior Year (%) Messages Sent to Patients Change in Patient Messages Sent to Patients from Prior Year (%) 2019 62,440 n/a 173,177 n/a 195,143 n/a 99,974 n/a 2020 61,959 -0.7 218,976 +26.5 240,833 +23.4 135,044 +35.1 2021 70,950 +14.5 276,561 +26.3 267,395 +11.0 165,293 +22.4 2022 74,961 +5.7 325,580 +17.7 263,732 -1.4 206,043 +24.7 2023 80,672 +7.6 349,756 +7.4 274,446 +4.0 214,257 +4.0 2024 87,605 +8.6 399,740 +14.3 319,963 +16.6 263,271 +22.9
The hidden toll: Defining impacts of home call on oncology fellows.
Andres, Erica, Liddell, S. , Marar, Rosalyn, Bentz, Caleb C., Go, Ronald S. , Paludo, Jonas , Godby, Richard

Journal of Clinical Oncology | May 28, 2025 | Volume: 43 | Issue: 16_suppl | Pages: 9021-9021

10.1200/jco.2025.43.16_suppl.9021 Get It

9021 Background: Home call is an expected trainee responsibility in many hematology-oncology (HO) training programs although the specific duties and frequency vary. Home call is associated with sleep deprivation and burnout . The Accreditation Council for Graduate Medical Education (ACGME) outlines that home call should not prevent adequate rest or personal time and that the clinical time spent must be counted toward duty hours. However, little is known about the educational value or impact of home call. We sought to analyze the volume, perceived value, and effects of oncology home call on HO fellows. Methods: We completed a review of the pager log of the outpatient/after hours oncology pager (OP) at a single 2059 bed tertiary medical center from 1/1/23-12/31/24. The HO fellow carries the OP afterhours and on weekends except for 7am-12pm on Saturday/Sunday. The pager receives all consult calls from the emergency department and inpatient teams requesting verbal communication (in addition to the electronic order), critical results, and outpatient patient calls on matters related to oncology (hematology not included). Patient calls are not triaged and are routed through the hospital operator directly to the OP. Overnight home call is maximum 3 times per week without a post call day. An optional survey was distributed to fellows in May 2024 to assess fellows’ experiences with the OP using a 5-point Likert scale and free response. Results: There were 80,672 and 87,605 oncology patient visits in 2023 and 2024 respectively at the analyzed institution. The OP received a total of 7,239 pages over the analyzed period. Fellows received a mean of 5.8 pages per weeknight call shift and 8.8 pages per weekend call shift. The survey response rate was 19/33 (42%) HO fellows. Respondents were 58% male and included first (42%), second (26%), and third year (32%) fellows. 89% of respondents reported that most pages overnight were from outpatients and 0 respondents felt that answering patient calls required a physician. Most fellows (79%) did not report educational value from holding the OP and 63% of fellows felt that holding the OP negatively impacted their performance at work the next day. For nights that received more than 3 calls, 95% fellows reported feeling not well rested. In addition, a majority of negative impact on their wellness including anxiety and inability to exercise or socialize when holding the OP. Conclusions: The results from our single-institution study indicate that home call could represent a major opportunity to improve the wellness of trainees without negatively impacting their education. More research is needed to understand what the primary contributors are for the negative experiences and perceptions while developing sustainable systems and approaches for efficiently handling oncology pager traffic.
Out of touch: Understanding the frequency and trajectory of chemotherapy-induced neuropathy peripheral (CIPN) in breast cancer survivors.
Liddell, S. , Loprinzi, Charles L. , Ruddy, Kathryn J. , Kournoutas, Ioannis , Vierkant, Robert A. , Larson, Nicole, Olson, Janet E. , Couch, Fergus J. , Cathcart-Rake, Elizabeth

Journal of Clinical Oncology | May 28, 2025 | Volume: 43 | Issue: 16_suppl | Pages: 12038-12038

10.1200/jco.2025.43.16_suppl.12038 Get It

12038 Background: CIPN, primarily associated with sensory neuropathy rather than motor or autonomic dysfunction, is a potentially long-term complication of cancer treatment including taxanes and platinums (T/Ps), and can negatively impact quality of life for breast cancer (BC) survivors. This project aims to quantify the severity of neuropathic symptoms at one and three years after diagnosis in BC survivors, comparing recipients of T/P to non-recipients. Methods: In the Mayo Clinic Breast Registry (MCBDR), a longitudinal cohort, surveys and medical record data from patients with stage 1-3 BC were used to understand the burden of neuropathic symptoms at 1- and 3-years post-diagnosis (denoted as Y1 and Y3). Y1 and Y3 raw scores from The Quality of Life Questionnaire-Chemotherapy-Induced Peripheral Neuropathy 20 (CIPN20) composite (CIPN20-C) and sensory subscale (CIPN-S) were converted to a 0-100 point scale, with lower scores corresponding to worse symptoms. Patients with BC recurrence prior to Y3 or incomplete surveys were excluded. We used two sample t-tests and multivariable linear regression modeling to compare recipients of T/P to non-recipients of T/P (with threshold for statistical significance p <0.05). Results: 786 patients were included, 112 of whom (14.2%) received T/P. T/P recipients were younger (p<0.001), more likely to have Stage II/III disease (p<0.001), and less likely to have received endocrine therapy (p<0.001). Univariate analyses revealed worse CIPN20-C score at Y1 (p=0.02) and worse CIPN20-S scores (p=0.004) at Y1 and Y3 in T/P recipients compared to non-recipients (Table). However, differences between the groups were no longer statistically significant after adjustment for age, stage and endocrine therapy. Conclusions: In this cohort, neuropathic symptom severity at Y1 and Y3 after a breast cancer diagnosis did not differ between recipients of taxane and/or platinum agents and nonrecipients after adjustment for age, stage, and endocrine therapy. These data may reassure patients and clinicians who are concerned about CIPN and considering use of these chemotherapies in this setting. Patient demographics and CIPN20 results. Clinical characteristic T/P recipients Non-recipients of T/P Age at diagnosis, mean (SD) 55.3 (11.6)* 59.8 (11.9) White race, N (%) 108 (96.4%) 660 (97.9%) Clinical stage II/III, N (%) 76 (68.5%)* 250 (37.5%) Endocrine therapy, N (%) 73 (65.2%)* 636 (94.4%) Diabetes mellitus, N (%) 9 (8.9%) 52 (8.6%) Y1 CIPN20-C score, mean (SD) 89.6 (10.9)* 92.0 (9.7) Y3 CIPN-C score, mean (SD) 89.4 (11.4) 91.1 (9.7) Y1 CIPN20- S score, mean (SD) 87.3 (15.1)* 91.3 (13.0) Y3 CIPN20-S score, mean (SD) 88.2 (14.1)* 91.1 (11.7) *Statistically significant (p <0.05) on univariate analysis.
Call Me Maybe: An Analysis of Hematology Fellowship Home-Call Burden, Perceptions, and Attitudes
Liddell, S. , Marar, Rosalyn, Bentz, Caleb C., Go, Ronald S. , Paludo, Jonas , Godby, Richard

Blood | December 5, 2024 | Volume: 144 | Issue: Supplement 1 | Pages: 5204-5204

10.1182/blood-2024-206131 Get It

Introduction: Traditional home-call, or the practice of holding a pager at home overnight to manage questions regarding patient care and direct patient calls, is a common component of hematology fellowship. Depending on the institution and training program, the frequency and expectations of home-call may vary. Home-call in fellowship is often performed overnight between two days of work without a “post-call” day to recover. As a field, medicine has entered the digital era, accompanied by changes in patient interactions and expectations involving after-hours calls. Little is known about modern non-digital interactions with patients such as after-hours calls in hematology practices and their effects on trainees. This project aims to evaluate the home-call pager burden and subjective experience in fellows. Methods: We analyzed Hematology Pager (HP) data from 7/1/19 - 4/14/23. The HPs for Mayo Clinic Rochester are covered by hematology fellows, including the weekend and after hours (6PM - 7AM) pagers. Those of interest were the Consults Pager (CP; covers new inpatient consults if discussion initiated outside of electronic order) and the Outpatient Pager (OP; covers direct patient calls as well as critical result communications for weekends and after-hours). The frequency of home-call varies based on each rotation but can require home-call up to 3-4 times per week with the expectation to occasionally present to the hospital overnight in the setting of a hematologic emergency. An optional survey was distributed to the fellowship in May 2024 with the intent to support trainee wellness and assess perceptions and attitudes toward the home-call experience. We allowed for free-text responses and used a 5-point Likert scale for structured responses. Results: The CP received a total of 5,304 pages during the analyzed period for a mean of 3.8 pages per day. Of those, 975 pages (18%) occurred after-hours and 1,250 (24%) during weekends. The OP received a total of 3,964 pages during the analyzed period, definitionally during weekends and/or after-hours, for a mean of 2.9 pages per day. The OP had the highest relative activity on weekends, which ranged from 1-18 calls per day. The survey captured 19/33 (58%) hematology/oncology fellows, which were comprised of 58% males and 42% females representing all levels of training with 42% PGY4s, 26% PGY5s, and 32% PGY6s. Over 85% felt that holding the HP was not an educational experience and that they did not learn about hematology while managing it. Moreover, 85% of respondents felt that they did not help patients get time-sensitive care when holding the HP. Only 5% felt that the majority of care provided through the HP required a Medical Degree and 32% agreed that the majority of calls were due to an acute clinical status change warranting immediate medical attention. If immediate medical attention was possibly required, 95% of fellows reported a recommendation of evaluation in the nearest emergency room. Over 85% of fellows felt that the HP affected other individuals (e.g., significant other) in their households. No respondents (0%) agreed that they could maintain their exercise schedule while holding the HP and only 16% reported no effect on their social life. Nearly all fellows reported not feeling well rested after a home call shift, regardless of whether the level of pager activity was low (≤2 calls), average (3-5 calls), or high (≥6 calls). Up to 95% of fellows reported feeling anxiety when holding the pagers. The free responses outlined concerns about sleep deprivation from call multiple times per week, the impact of home-call on learning, and the desire for a process that triaged patient calls at night that did not require physician resource utilization. Conclusions: Home-call is a long-standing tradition that gives hospital teams and patients access to specialty care after standard business hours. However, home-call can impact wellness, contribute to fatigue, and affect learning. To our knowledge, this is the first analysis evaluating call pager volumes and hematology fellows' perceptions and attitudes toward the home-call experience. Hematology is a dynamic field that requires empathy, critical thinking, and physician wellness to provide the best possible care to patients. In the digital era, the current structure of this long-standing tradition may warrant reevaluation and optimization to prioritize a system beneficial for both patient care and physician wellness.
Tumor Mutational Burden Is a Potential Predictive Biomarker for Response to Immune Checkpoint Inhibitors in Patients With Advanced Biliary Tract Cancer
Liddell, S. , Chakrabarti, Sakti , Wintheiser, Grant , Shi, Qian , Tella, Sri Harsha , Jin, Zhaohui , Wookey, Vanessa, Hassan, Hind , Tran, Nguyen H. , Liddell, Savannah S , Wintheiser, Grant A , Zemla, Tyler J, Shi, Qian , Jin, Zhaohui , Wookey, Vanessa B, Tran, Nguyen , Borad, Mitesh J , Mahipal, Amit , Chakrabarti, Sakti , Zemla, Tyler , Borad, Mitesh J. , Mahipal, Amit

JCO Precision Oncology | June 30, 2022 | Volume: No volume available | Issue: 6 | Pages: No page available

10.1200/po.22.00003 Get It

PURPOSE Patients with advanced biliary tract cancers (BTCs) have a dismal prognosis. This multisite, single-institution study analyzed the efficacy and safety of immune checkpoint inhibitors (ICIs) in patients with advanced BTC. MATERIALS AND METHODS The prospectively maintained institutional database was searched for patients with advanced BTC. Electronic medical records of the patients with advanced BTC treated with an ICI that included programmed death-1 or programmed death-ligand 1 blockers were retrospectively reviewed to obtain data on patient characteristics, tumor characteristics including molecular biomarkers, detailed treatment, response characteristics, survival, and toxicities. The analysis included overall response rate, survival, and correlation between survival and molecular biomarkers. RESULTS The institutional database query identified 47 patients with advanced BTC who received at least one dose of an ICI; 11 (24%) patients in the first-line setting and the rest of the patients had refractory disease. The median age of the cohort was 62 years, and 51% were female. The overall response rate was 10.6%, with a disease control rate of 53.2%. The median progression-free survival (PFS) and overall survival were 3.6 months and 6.9 months, respectively. Biomarker analysis revealed improved PFS in patients with tumor mutational burden > 5 mutations per megabase (median PFS: 6.4 v 2.2 months; P = .0027). No unexpected adverse events were observed. CONCLUSION ICIs are well tolerated and have modest antitumor activity in patients with advanced BTC. The study result supports the exploration of tumor mutational burden as a potential predictive biomarker for response to ICIs in patients with advanced BTC.
Clinical Management of Metastatic Hormone Receptor-Positive, HER2-negative Breast Cancer (MBC) After CDK 4/6 inhibitors: A Retrospective Single-Institution Study
Choong, Grace M. , Liddell, S. , Leon‐Ferre, Roberto A. , O’Sullivan, Ciara C. , Ruddy, Kathryn J. , Haddad, Tufia C. , Hobday, Timothy J. , Peethambaram, Prema P. , Liu, Minetta C. , Choong, Grace M , Goetz, Matthew P. , Giridhar, Karthik V.

No container title available | May 3, 2022 | Volume: No volume available | Issue: No issue available | Pages: No page available

10.21203/rs.3.rs-1601792/v1 Get It

Abstract Purpose Cyclin dependent kinase 4/6 inhibitors (CDK4/6is), in combination with endocrine therapy (ET), are standard either in the first (1L) or second line (2L) setting for the treatment of hormone receptor (HR) positive, HER2-negative metastatic breast cancer (MBC). However, the optimal sequencing of treatments after progression on CDK4/6i remains unknown. We performed a single institution analysis to identify treatments and outcomes after progression on a CDK4/6i. Methods We identified patients with HR-positive, HER2-negative MBC prescribed a CDK4/6i in the 1L or 2L settings from December 2014-February 2018 at Mayo Clinic in Rochester, Minnesota. Outcomes were collected through September 30, 2020. Results Palbociclib, in combination with letrozole or fulvestrant, was the most prescribed CDK4/6i. The 1L and 2L CDK4/6i cohorts exhibited comparable overall survival (OS), but progression free survival (PFS) was longer in the 1L than the 2L cohort [28.2 months (95% CI 19.6–34.9) vs 19.8 months (95% CI 15.7–29.6)]. The most common post-CDK4/6i treatments were PI3K/mTOR inhibitors (PI3K/mTORi), single agent ET, or chemotherapy. PFS in the 1L CDK4/6i cohort following PI3K/mTORi was 8.5 months (95% CI 5.5 months – NE), single-agent ET was 6.0 months (95% CI 3.3–14.0 months), and chemotherapy PFS was 5.4 months (95% CI 3.3 months- NE). Conclusions Following progression on a CDK 4/6i, mPFS was short, with similar PFS times comparing chemotherapy and ET, with slightly longer PFS for targeted strategies (PI3K/mTOR). These results highlight a major need to better understand the mechanisms of CDK4/6i resistance and identify new therapeutic strategies for these patients.