About

Kristin Leigh Bixel is an Associate Professor of Obstetrics and Gynecology at Stanford Medicine, specializing in Gynecologic Oncology. She holds board certifications in Obstetrics and Gynecology as well as Gynecologic Oncology, obtained in 2019 and 2021 respectively. Her academic appointment includes serving as the Director of the Gynecologic Oncology Clinical Research Group since 2024. Her research focuses on gynecologic cancers, with notable contributions including her work on sentinel lymphadenectomy for early-stage cervical cancer, published in the New England Journal of Medicine in 2025. She has also contributed to case reports and studies on recurrent neuroendocrine cervical cancer, demonstrating the efficacy of targeted therapies such as trastuzumab deruxtecan in rare and aggressive cancer subtypes. Bixel's work emphasizes biomarker-driven therapy approaches and advances in surgical and clinical management of gynecologic malignancies.

Research topics

• Internal medicine
• Medicine
• Surgery
• Oncology
• Pharmacology
• Psychology
• Cancer research

Selected publications

• Abstract 1412: Informatics-driven spatial-omics for cancer immunotherapy discovery in gynecologic cancers.

  Cancer Research · 2026-04-03

  article

  Abstract Endometrial cancer (EC) remains a highly prevalent and understudied malignancy, with aggressive subtypes disproportionately affecting underrepresented populations and lacking effective targeted therapies. Traditional bulk sequencing approaches have provided limited insight into the spatial and cellular heterogeneity that drive EC progression, particularly with respect to how tumor cells interact with their microenvironment and evade the immune system. Our current research focuses on directly addressing these gaps by leveraging large, well-annotated retrospective EC cohorts to apply advanced spatial multi-omics and computational frameworks. We propose SPATIAM (Spatial Partitioning of Tumor-Immune Architecture via Multi-omics), a novel computational framework integrating spatial genomics, transcriptomics, and proteomics at single-cell resolution to reconstruct tumor subclonal architecture and map dynamic tumor-immune-stromal interactions in situ. This approach resolves how genetically distinct subclones emerge and interact with their microenvironment and identifies spatially organized immune evasion mechanisms that are invisible in bulk analyses. Our longitudinal cohort (unpublished) includes patients treated with immune checkpoint inhibitors, with longitudinal sampling of matched primary untreated, post-chemotherapy, interim (on treatment) immune checkpoint inhibition (ICI) and post-ICI samples. This comprehensive collection was processed into tissue microarrays (TMAs) and subjected to multi-modal spatial and molecular profiling. We employed GeoMx Digital Spatial Profiling for high-plex protein and RNA analysis, Multiplexed Ion Beam Imaging (MIBI) for high-resolution spatial proteomics, and single nucleus RNA sequencing for unbiased transcriptional profiling at single cell resolution. This multi-modal approach enabled the systematic characterization of tumor microenvironment evolution throughout the treatment course, capturing both spatial and molecular dynamics of immune responses. This pioneering study presents the first longitudinal, multi-modal spatial and molecular atlas of ICI treatment evolution, integrating samples across treatment timepoints with cutting-edge spatial proteomics, digital spatial profiling, and single-nucleus sequencing to uncover novel mechanisms of therapeutic resistance. Citation Format: Rongting Huang, Diane Libert, Arslan Kasimov, Leandra Kingsley, Sahar Nasr, Reem Al-Humadi, Lindsey A. Finch, Elisabeth Diver, Ravali A. Reddy, Babak Litkouhi, Kristin Bixel, Sizun Jiang, Brooke Howitt. Informatics-driven spatial-omics for cancer immunotherapy discovery in gynecologic cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 1412.

  PublisherDOI

• Evaluation of immunotherapy response in the radiated field in patients with recurrent endometrial and cervical cancer

  Gynecologic Oncology · 2025-09-01

  article
  PublisherDOI

• Exploratory evaluation of immunotherapy response and medication use in endometrial and cervical carcinoma

  Gynecologic Oncology Reports · 2025-06-21

  articleOpen access

  Objective: To assess the effect of medication use during immune checkpoint inhibitor (ICI) therapy on treatment response and oncologic outcomes. Methods: An IRB-approved single-institution retrospective cohort study was performed in patients with endometrial cancer (EC) and cervical cancer (CC) who were treated with ICIs from January 1, 2017 to January 1, 2023. Concomitant medications used during the ICI course were recorded. The associations between medication use and ICI response, progression-free survival (PFS), and overall survival (OS) was assessed. Results: 217 CC and EC patients were treated with ICIs during this study period; 32 % (n = 71) had CC, and 67 % (n = 146) had EC. There was a significant difference in ICI complete response between CC patients who did and did not use oral steroids during treatment. Of CC patients who achieved a complete response, 28 % (n = 7) used steroids vs. 13.6 % (n = 6) of non-steroid users (Fisher's exact p = 0.045). In patients with EC, proton pump inhibitor (PPI) use was associated with ICI response, with 43.8 % (n = 21) of PPI users achieving a complete response vs. 16.3 % (n = 15) of non-PPI users (chi-squared p = 0.002). PPI use in the EC cohort was associated with improved progression-free survival and overall survival (log-rank p < 0.05). This was also demonstrated among mismatch repair-deficient EC patients where PPI use during ICI therapy significantly associated with both PFS (HR 0.26, 95 % CI 0.12-0.55; p < 0.001) and OS (HR 0.22, 95 % CI 0.08-0.59; p < 0.001).Conclusion(s)In this retrospective cohort study of EC and CC patients treated with ICI therapy, medication use, specifically PPIs and oral steroids, was seen to have a significant positive effect on ICI response, PFS, and OS.

  PublisherDOI

• The impact of antibiotics, proton pump inhibitors, H2-receptor antagonists, and steroids on survival in ovarian cancer patients receiving PARP inhibitor therapy

  Gynecologic Oncology · 2025-05-31

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  PublisherDOI

• Exceptional response to trastuzumab deruxtecan in recurrent neuroendocrine cervical cancer: A case report

  Gynecologic Oncology Reports · 2025-06-26 · 3 citations

  articleOpen accessSenior authorCorresponding

  Objective: Neuroendocrine cervical carcinomas (NECC) are a rare and aggressive cervical cancer subtype that account for 1-1.5 % of all cervical cancers. Treatment options for recurrent NECC are limited and anticipated response rates are low. Trastuzumab deruxtecan (T-DXd), an antibody drug conjugate with a topoisomerase I inhibitor payload, recently received FDA approval for previously treated patients with HER2+ (IHC3 + ) metastatic solid tumors. Data regarding use of T-DXd in NECC is very limited and it is unclear whether this histology was represented in the trial leading to approval. We sought to describe this unique case of a patient with recurrent NECC who experienced a complete and durable response to T-DXd. Methods: This is a case report and review of the literature. Written informed consent was obtained by the patient prior to submission. Results: We describe a 44-year-old patient with recurrent, metastatic NECC who progressed following two prior lines of therapy, the most recent of which included a multi-drug regimen with topotecan (a topoisomerase I inhibitor). IHC of her tumor tissue demonstrated 3 + HER 2 expression leading to the decision to proceed with treatment with T-DXd. She experienced a partial response (64 % decrease by RECIST) at C6 and subsequent complete response which has now been maintained for > 1 year. She has tolerated therapy well with manageable toxicities and has not required treatment interruption to date. Conclusions: This report demonstrates the role of biomarker driven therapy for rare and aggressive cancer subtypes such as NECC and demonstrates efficacy of T-DXd after previous exposure to topoisomerase I inhibitors.

  PublisherDOI

• Prognostic significance of ethnicity and age in advanced stage epithelial ovarian cancer: An NRG oncology/gynecologic oncology group study

  UNC Libraries · 2025-05-16

  articleOpen access
  PublisherDOI

• ROCC/GOG-3043: a randomized controlled trial of robotic versus open surgery for early-stage cervical cancer

  International Journal of Gynecological Cancer · 2025-02-28 · 8 citations

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  PublisherDOI

• Management of Recurrent Endometrial Cancer Once Lifetime Cumulative Dose of Doxorubicin Has Been Reached: Is There a Role for Switching to Pegylated Liposomal Doxorubicin?

  SSRN Electronic Journal · 2025-01-01

  preprintOpen accessSenior author
  PublisherDOI

• Defining “enlarged” sentinel lymph nodes in the setting of endometrial cancer: What is the size cut-off?

  Gynecologic Oncology · 2025-02-18

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  PublisherDOI

• Atezolizumab and stereotactic body radiation in metastatic, recurrent, or persistent cervical cancer: Results from a phase II multi-institutional study.

  Journal of Clinical Oncology · 2025-05-28

  article

  5536 Background: Pembrolizumab is approved for PD-L1+ but not PD-L1 negative metastatic, recurrent, or persistent cervical cancer. Response rates to single agent anti-PD-1/PD-L1 therapy have been modest with no responses noted in PD-L1 negative tumors. Methods: The study is designed as a prospective, phase II multi-institutional trial of SBRT followed by atezolizumab (1200 mg intravenously q3 weeks). Key eligibility criteria included patients with metastatic, recurrent, or persistent cervical cancer with at least 2 distinct lesions. The primary objective was objective response rate measured at the unirradiated target lesion. Secondary endpoints included overall response, progression free survival (PFS), overall survival (OS), and adverse events. Clinical trial information: NCT03614949. Results: A total of 21 patients were enrolled. Median follow-up is 23.6 months. The majority of patients had adenocarcinoma (n=10; 48%) and were PD-L1 negative (n=15; 71%). The best overall response was a partial response in 5 (24%) and stable disease in 12 (57%) patients. The median duration of response was 8.6 months (95% CI: 4.5-13.6 months). An objective response at the unirradiated target lesion was observed in 8 patients (38%), meeting the study defined endpoint. Responses were noted in PD-L1 negative tumors. The median PFS was 4.7 months (95% CI: 3.9- 7.4) with a 6-month PFS of 48%. The median OS was 26 months (95% CI 7.6 – 54) with a 6-month OS of 76%. No differences were noted in OS or PFS by PD-L1 status. The most common grade ≥ 2 toxicities at least possibly attributed to study therapy included lymphopenia (n=6; 29%), nausea/vomiting (n=3; 14%), and hyponatremia (n=3; 14%). Conclusions: In this first trial of SBRT and atezolizumab in metastatic cervical cancer unselected for PD-L1, combination therapy was well tolerated. Responses were noted in PD-L1 negative tumors. Combination therapy may allow for improved response rates to immune checkpoint inhibition in metastatic cervical cancer particularly in PD-L1 negative tumors. Clinical trial information: NCT03614949 .

  PublisherDOI

Frequent coauthors

• David M. O’Malley

  The Ohio State University

  143 shared

• David E. Cohn

  The Ohio State University Comprehensive Cancer Center – Arthur G. James Cancer Hospital and Richard J. Solove Research Institute

  119 shared

• Floor J. Backes

  106 shared

• Larry J. Copeland

  105 shared

• Casey Cosgrove

  101 shared

• Christa Nagel

  51 shared

• Monica Hagan Vetter

  University Hospital in Halle

  50 shared

• Ritu Salani

  49 shared

Labs

• Kristin Leigh BixelPI

Education

• M.D.

  Stanford University

• B.A.

  University of California, Berkeley

Awards & honors

• Ohio State University Gynecologic Oncology Fellowship (2017)