Kaitlyn Lapen

Kaitlyn Lapen, MD

Areas of Expertise

Conditions I Treat

  • Breast cancers and conditions
  • Brain metastases

My Specialties

  • External beam radiation
  • Intensity-modulated radiation therapy (IMRT)
  • Image-guided radiation therapy (IGRT)
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Get to Know Me

I’m a radiation oncologist who is an expert in caring for people with breast cancer. I also care for people with metastatic cancer, or cancer that has spread to the lungs, bones, spine, brain, or other organs. I see patients on Long Island at Memorial Sloan Kettering Cancer Center (MSK) Nassau on Long Island.

I have special training in treating patients using radiation therapy. I use the latest radiation techniques to provide treatment tailored to each person. We also work to reduce side effects of treatment and its impact on patients’ daily lives.

My goal is to provide thoughtful care that is based on actual data. I take into account not only a patient’s diagnosis, but also their specific needs, priorities, and quality of life. I believe it’s important for patients to understand the role radiation can play in their care. This helps us make treatment decisions together.

I was drawn to cancer care because of the relationships we build with patients and family during a challenging time. I believe in clear communication and making decisions together.

I take the time to explain treatment options, answer questions, and understand what matters most to each person. I work with each patient to develop a treatment plan that reflects their personal situation and goals. I cherish the trust that patients place in me and provide the care that I would want for my own loved ones.

I also work closely with a team of different experts. This includes breast surgeons, medical oncologists, radiologists, pathologists, and other specialists. Together, we make sure each patient receives complete and coordinated care. This approach is one of MSK’s great strengths and allows us to provide the best possible care for each patient.

Cancer care is advancing rapidly, and I make sure my recommendations are guided by the latest data. Besides high-quality care, MSK offers access to clinical trials. When a clinical trial may be suitable, I discuss the option with my patients. I also explain the potential benefits, risks, and alternatives so they can make an informed decision about their care.

In addition to caring for patients, my research focuses on improving the experience and quality of cancer care. I’m especially interested in how patients report feeling and functioning, health equity, and understanding how we can better identify and address symptoms during and after radiation therapy. Ultimately, my goal is to use what we learn directly from patients to make cancer treatment more personal, accessible, and focused on the patient.

Outside of work, I enjoy distance running, trying new cuisines and recipes, and spending time with friends and family.

What I Do at MSK

I'm a radiation oncologist, which is a cancer doctor with special training in using radiation therapy (RT) to treat cancer.

  • Assistant Attending Physician
Areas of Expertise

Conditions I Treat

  • Breast cancers and conditions
  • Brain metastases

My Specialties

  • External beam radiation
  • Intensity-modulated radiation therapy (IMRT)
  • Image-guided radiation therapy (IGRT)
  • Volumetric modulated arc therapy (VMAT)
  • Stereotactic body radiation therapy (SBRT)
  • Stereotactic radiosurgery (SRS)
This list shows some key areas of focus, but it may not cover all expertise. When making an appointment, you will be matched with the best healthcare provider for your needs.
Education & Honors

Education

  • Bachelor of Science., Emory University
  • MD, University of Illinois College of Medicine

Residencies

  • Transitional Year Internship, Memorial Sloan Kettering Cancer Center
  • Radiation Oncology, Memorial Sloan Kettering Cancer Center

Fellowships

  • Lymphoma Radiation Therapy Fellowship, Memorial Sloan Kettering Cancer Center

Awards and Honors

  • Young Investigator Award, Cutaneous Lymphoma Foundation (2025)
  • Conquer Cancer Merit Award, American Society of Clinical Oncology (ASCO) (2024)
  • Graduate with Honors, University of Illinois College of Medicine (2021)
  • Alpha Omega Alpha Honor Medical Society, University of Illinois Chapter (2020)
  • Gold Humanism Honor Society, University of Illinois Chapter (2020)
  • University of Illinois College of Medicine Merit-Based Scholarship (2016)

Insurance Information

Understanding your insurance options is an important part of managing your cancer care. We have relationships with many common healthcare providers and plans.

Learn more about the insurance plans that participate with MSK.

If you don't have health insurance or are worried that your care may not be fully covered, our financial assistance programs may be able to help.

Health plans can change at any time. Call the number on the back of your insurance card to see what your plan covers. Make sure it covers the MSK location where you’ll get care.

If you have questions about insurance, call us at 646-497-9176.

Make an Appointment

Current Patients
Request an appointment by calling your Care Team or messaging them in MSK MyChart.

Contact and Location

Location
Uniondale, NY
1101 Hempstead Turnpike Uniondale NY 11553

Looking to see a doctor at a different location? See all MSK locations.

Colleagues

Doctors at Memorial Sloan Kettering work as teams, with specialists from all different areas. This allows us to consider all your needs together, and to give you the best possible care.

See all External Beam Radiotherapy Service, Regional Care Network doctors

See all Radiation Oncology doctors

Clinical Trials

Smiling doctors in the lab
Find a Clinical Trial for You

Memorial Sloan Kettering's doctors and scientists are constantly developing new treatments for cancer. MSK is typically running hundreds of clinical trials at a given time.

You may be able to participate in a clinical trial even if you are new to MSK. Search our online directory to find trial information and see more about who can participate.

Search clinical trials

Research and Publications

  1. Lapen K, Zhang Z, White C, Barker CA, Kotecha R, McIntosh AF, Nipp RD, Iyengar P, Yang JT, Yerramilli D, Gillespie EF. Predictors of Skeletal-Related Events and Quality-of-Life Dimensions Among Patients With High-Risk Asymptomatic Bone Metastases With or Without Early Radiation Therapy: Secondary Analysis of a Multicenter Randomized Phase II Clinical Trial. J Natl Compr Canc Netw. 2026 Mar 9;24(4):e257126. doi: 10.6004/jnccn.2025.7126. PMID: 41825136.
  2. Miller DG, Lapen K, Dee EC, Meske S, Weiss MC, Chino JP, Chino F. Fear and Medical Misinformation Regarding Risk of Progression or Recurrence Among Patients with Breast Cancer. JAMA Netw Open. 2025 Dec 1;8(12):e2549809. doi: 10.1001/jamanetworkopen.2025.49809. PMID: 41632168; PMCID: PMC12750251.
  3. Teles MS, Lapen K, Huang J, Mao JJ, Bernstein MB, Braunstein LZ, Khan AJ, Daly B, Gillespie EF. Assessing the Implementation of Electronic Patient-Reported Outcomes (ePRO) to Reduce Follow-up Visits for Patients Undergoing Radiation Therapy for Breast Cancer. Int J Radiat Oncol Biol Phys. 2026 Mar 1;124(3):641-646. doi: 10.1016/j.ijrobp.2025.09.027. Epub 2025 Sep 28. PMID: 41027545.
  4. Narayan A, Lapen K, Dee EC, Thom B, Aviki EM, Chino F. Screening for Financial Toxicity and Health-Related Social Risks in Patients With GI Cancer: Results From a Large Cancer Center. JCO Oncol Pract. 2026 May;22(5):868-876. doi: 10.1200/OP-25-00218. Epub 2025 Jul 11. PMID: 40644642; PMCID: PMC12258957.
  5. Lapen K, Sabol C, Tin AL, Lynch K, Kassa A, Mabli X, Ford J, Cha E, Bernstein MB, Braunstein LZ, Cahlon O, Daly BM, Sandler K, McCloskey SA, Vickers AJ, Khan AJ, Gillespie EF. Development and Pilot Implementation of a Remote Monitoring System for Acute Toxicity Using Electronic Patient-Reported Outcomes for Patients Undergoing Radiation Therapy for Breast Cancer. Int J Radiat Oncol Biol Phys. 2021 Nov 15;111(4):979-991. doi: 10.1016/j.ijrobp.2021.07.1692. Epub 2021 Jul 24. PMID: 34314814; PMCID: PMC8530913.
Publications on PubMed

Visit PubMed for a full listing of Dr. Lapen’s journal articles. Pubmed is an online index of research papers and other articles from the US National Library of Medicine and the National Institutes of Health.

See all on PubMed