This Giving Smarter Guide describes the current state of research, clinical practice, and treatment approaches for uterine leiomyosarcoma (uLMS) and identifies critical areas where philanthropy can significantly advance scientific knowledge and improve patient care. This report is made possible by the Briger Foundation for Oncology Research’s partnership with Milken Institute’s Science Philanthropy Accelerator for Research and Collaboration.

uLMS is a rare, aggressive gynecologic cancer that mostly commonly affects perimenopausal women between the ages of 45 and 60. It originates in the uterus, after which it tends to grow rapidly, metastasize, and recur. People diagnosed with uLMS generally receive a poor prognosis, especially if the cancer has already metastasized by the time of diagnosis.

In addition to its aggressive behavior, uLMS is especially challenging to diagnose and treat for other reasons:

• uLMS often shares many attributes with uterine fibroids, which are benign and extremely common. Clinicians may misidentify some uterine masses in their patients as fibroids instead of as actual incidences of uLMS. Clinicians may then monitor as-yet-undiagnosed uLMS patients insufficiently closely or remove the masses surgically without heightened concern for malignancy. Meanwhile, unrecognized uLMS tumors may grow or spread.
• After clinicians diagnose uLMS, they have few effective treatment options to offer their patients. The first step of treatment is surgically removing the tumor, but parts of the tumor may be left behind, or the cancer may recur entirely. Unlike some other cancers, the Food and Drug Administration has not approved targeted therapies specifically for uLMS, and neither chemotherapy nor radiation has demonstrated promise in this particular cancer.
• It has been challenging for researchers and clinicians to develop effective therapies for uLMS. The biological changes that cause uLMS to develop in the body are complex and varied. Any of several combinations of changes to someone’s genetic, epigenetic, metabolic, or immune features can cause uLMS. This heterogeneity has made it challenging for researchers and clinicians to understand uLMS well enough to develop therapies that fight the disease effectively.
• uLMS remains significantly underfunded compared to other gynecologic cancers. Significant, sustained funding is needed to advance research and clinical care.

People living with this rare cancer urgently need more effective care that is informed by better scientific understanding of uLMS’s underlying biology—both of which rely on a more robust funding landscape supported by philanthropic investment.