Researchers in Poland tested ovarian cancer tumors to see which patients might benefit from a newer type of cancer treatment called mirvetuximab soravtansine. They looked for a specific marker called folate receptor alpha (FRα) on cancer cells. About half of the 229 ovarian cancer samples they studied had this marker, which means those patients could potentially use this new treatment. This is the first study from Poland showing how common this marker is in their patient population, which helps doctors decide who should get tested and treated with this newer medicine.

The Quick Take

  • What they studied: How many ovarian cancer patients in Poland have a specific marker on their cancer cells that would make them eligible for a newer treatment drug
  • Who participated: 229 women with ovarian cancer from two major cancer hospitals in Poland (Bydgoszcz and Warsaw)
  • Key finding: About 51 out of every 100 ovarian cancer patients had the marker they were looking for, with 40% showing strong levels of it. This means roughly half of Polish ovarian cancer patients might be able to use this newer treatment option
  • What it means for you: If you or someone you know has ovarian cancer that hasn’t responded well to standard treatments, asking your doctor about this test could help determine if a newer treatment option is available. However, this is just one study, and your doctor should help decide if testing makes sense for your situation

The Research Details

Researchers looked back at cancer tissue samples from 229 patients treated at two major Polish cancer hospitals. They used a special staining test (called immunohistochemistry) to look for a specific protein marker called folate receptor alpha on the cancer cells. This marker is important because it shows which patients might benefit from a newer drug called mirvetuximab soravtansine. The researchers counted how many cells had this marker and how strong the staining was, then compared their findings to what other countries have reported.

The test they used is standardized and approved by health authorities, meaning it follows strict rules about how to perform it and read the results. They looked at tissue that had been preserved in a special way (formalin-fixed, paraffin-embedded), which is the standard method for storing cancer samples. A tumor was considered positive for the marker if at least 75% of the cancer cells showed moderate to strong staining.

This research approach is important because it shows real-world data from Poland about how common this marker is in their patient population. Different countries and different types of ovarian cancer may have different rates of this marker, so having local data helps Polish doctors know how many of their patients might benefit from this newer treatment. This kind of practical information helps healthcare systems plan which patients should be tested and how to make the new treatment available to those who need it.

This study used a standardized, approved testing method that is reliable and consistent. The researchers tested samples from two different major cancer centers, which makes the results more trustworthy than if they had only used one hospital. However, this is a retrospective study, meaning they looked back at old samples rather than following patients forward in time. The study doesn’t tell us whether patients who had this marker actually benefited from the newer treatment—it only shows who could potentially use it. The researchers were honest about limitations and noted that their results may differ from other countries due to differences in cancer types and testing methods.

What the Results Show

Out of 229 ovarian cancer tissue samples tested, 116 samples (about 51%) showed the folate receptor alpha marker at levels that would make patients eligible for the newer treatment. Of these positive cases, 40% showed high levels of the marker. Most of the positive cases had moderate to strong staining, which is what doctors look for when deciding if a patient can use mirvetuximab soravtansine.

About 18% of the tumors fell into a borderline range, meaning they had between 65-85% of cells with the marker. These borderline cases are interesting because they’re close to the cutoff but don’t quite meet the standard criteria for treatment eligibility. The researchers noted that the 51% positive rate in Poland is somewhat lower than what has been reported in other countries, particularly in studies looking at high-grade serous carcinoma (a specific type of ovarian cancer).

The difference in rates between Poland and other countries likely comes from two main reasons: first, the Polish study included different types of ovarian cancer (not just the high-grade serous type), and second, different hospitals may use slightly different testing methods or criteria for what counts as positive.

The study found that the type of ovarian cancer mattered—different subtypes had different rates of the marker. The researchers also noted that the testing method they used (VENTANA FOLR1 assay) was consistent and reliable across both hospitals, which is reassuring for doctors who want to use this test. The fact that about 40% of positive cases showed high expression (rather than just moderate) suggests that a substantial portion of eligible patients have strong marker presence, which might predict better response to treatment.

Previous studies from other countries, particularly those focusing on high-grade serous ovarian cancer, reported higher rates of this marker (sometimes 60-70% or more). The Polish study’s 51% rate is lower, but this appears to be because they included all types of epithelial ovarian cancer, not just the high-grade serous type. The researchers suggest this difference is expected and doesn’t mean the marker is less important in Poland—it just reflects the mix of cancer types in their patient population.

This study only looked at tissue samples from the past, so it couldn’t follow patients forward to see if those with the marker actually benefited from the newer treatment. The study doesn’t tell us anything about whether the treatment actually works better in Polish patients compared to other populations. The researchers only tested samples from two hospitals in Poland, so results might be different in other parts of the country. Additionally, the study doesn’t include information about other factors that might affect treatment success, such as patient age, overall health, or how advanced the cancer was. Finally, because this is a retrospective study, some patient information may have been incomplete or missing.

The Bottom Line

If you have ovarian cancer that has stopped responding to platinum-based chemotherapy (the standard first-line treatment), ask your oncologist about testing for the folate receptor alpha marker. If your tumor tests positive, mirvetuximab soravtansine may be an option worth discussing. This recommendation is based on solid evidence that the marker predicts which patients can use this drug, though more research is needed to confirm how much it actually helps patients. Confidence level: Moderate—the test is reliable, but we need more studies showing it actually improves outcomes.

This research is most relevant for women with platinum-resistant ovarian cancer (cancer that has come back or stopped responding to standard chemotherapy). It’s also important for oncologists in Poland and similar populations who need to know how many of their patients might be eligible for this newer treatment. Healthcare systems and insurance companies should care because it helps them plan which patients to test and how to allocate resources for this newer, likely more expensive treatment. This research is less immediately relevant for people with early-stage ovarian cancer or those whose cancer is still responding well to standard treatments.

If you test positive for the marker and start mirvetuximab soravtansine, you would typically see initial signs of whether it’s working within 2-3 months (through imaging scans and tumor marker blood tests). Full benefits might take 3-6 months to become clear. However, this timeline varies by individual, and your doctor would monitor you closely with regular scans and blood work.

Want to Apply This Research?

  • If using a health tracking app, record the date of your folate receptor alpha test and result (positive/negative/borderline), along with any treatment decisions made based on that result. Track any new treatments started and note scan dates and results every 2-3 months to monitor response.
  • Work with your oncology team to schedule the folate receptor alpha test if you have platinum-resistant ovarian cancer. Use the app to set reminders for follow-up appointments and imaging scans. Document any side effects or symptoms related to treatment in the app to share with your care team.
  • Long-term, use the app to maintain a timeline of all tests (including the folate receptor alpha test), treatment dates, scan results, and CA-125 tumor marker blood tests. This creates a comprehensive record to share with your medical team and helps track whether the treatment is working over months and years.

This research describes a test to identify which ovarian cancer patients might be eligible for a specific treatment. It does not provide medical advice or treatment recommendations. If you have ovarian cancer or suspect you might, please consult with your oncologist or healthcare provider. The findings are based on a Polish population and may not apply equally to all populations. Testing availability and treatment options vary by location and healthcare system. Always discuss any new treatment options with your medical team before making decisions.