What is Platinum-Sensitive vs Resistant Ovarian Cancer?
At a Glance
Platinum-sensitive ovarian cancer returns more than six months after platinum chemotherapy, meaning it may still respond to platinum drugs. Platinum-resistant cancer returns within six months and is usually treated with non-platinum chemotherapy or targeted therapies instead.
In this answer
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When a doctor describes ovarian cancer as platinum-sensitive or platinum-resistant, they are referring to how much time has passed between your last dose of platinum-based chemotherapy (such as carboplatin or cisplatin) and when the cancer returned. If the cancer returns more than six months after you finish platinum treatment, it is considered platinum-sensitive [1]. If the cancer returns within six months, it is considered platinum-resistant [2].
This timeframe is clinically known as the platinum-free interval (PFI) [1]. It is one of the most important pieces of information your care team uses to plan your next steps, as it helps predict which treatments are most likely to work against the returning cancer [1].
The Spectrum of Platinum Sensitivity
While the six-month mark is a standard cutoff, sensitivity exists on a spectrum. You might hear the term partially platinum-sensitive if your cancer returns between 6 and 12 months after treatment, whereas cancer returning after more than 12 months is highly sensitive [3]. If your recurrence happens right on the edge of the six-month mark, your doctor will look at the nuances of your specific case to decide the best path forward [4].
Platinum-Sensitive Ovarian Cancer
If your cancer is platinum-sensitive, it means the cancer cells still respond well to platinum-based drugs. Because it took a longer time for the cancer to return, there is a good chance these medications will be effective again [5].
The standard treatment strategy usually involves:
- Platinum-based combination chemotherapy: You will likely receive another round of platinum therapy combined with another drug. This approach is associated with better survival outcomes compared to switching to non-platinum drugs [5][1].
- PARP inhibitors: These targeted therapies (such as olaparib or niraparib) are drugs that block cancer cells from repairing their damaged DNA. They are widely used as “maintenance therapy” to delay the cancer from returning again after your new round of chemotherapy [6][7]. While highly effective for patients with BRCA mutations or homologous recombination deficiency (HRD), they can also provide benefits regardless of your genetic mutation status [8].
- Additional options: Depending on your overall health, your doctor might also recommend incorporating bevacizumab—a drug that starves tumors of their blood supply—or performing a secondary surgery to remove visible tumors before starting chemotherapy [9][10].
Platinum-Resistant Ovarian Cancer
If your cancer is platinum-resistant, it means the cancer cells have adapted and built up a defense against platinum drugs. Giving you more platinum chemotherapy is unlikely to be helpful. Instead, your care team will pivot to different strategies to bypass the cancer’s resistance:
- Non-platinum chemotherapy: Rather than using combinations, you will typically be treated with a single non-platinum chemotherapy drug, such as pegylated liposomal doxorubicin, paclitaxel, or gemcitabine [11]. These single-agent therapies often have different side effect profiles than your initial heavy platinum combination, which your doctor can help you manage. Bevacizumab may also be added to this single-agent chemotherapy to improve its effectiveness [12].
- Targeted therapy: A relatively new class of drugs called antibody-drug conjugates (ADCs) can be an excellent option [13]. For example, the FDA-approved drug mirvetuximab soravtansine delivers targeted chemotherapy directly to cancer cells if specialized testing shows your tumor expresses a specific protein called folate receptor-alpha (FRα) [14][15].
- Clinical trials: Because platinum-resistant cancer can be more challenging to treat, participating in clinical trials is highly encouraged [16]. Clinical trials offer access to promising new cutting-edge strategies—such as combining PARP inhibitors with immunotherapies or other targeted agents to overcome the cancer’s resistance—that are being studied to see if they can improve survival over standard options [17][16].
Common questions in this guide
What is the platinum-free interval (PFI)?
What does it mean if my ovarian cancer is platinum-sensitive?
How is platinum-resistant ovarian cancer treated?
What is partially platinum-sensitive ovarian cancer?
Questions to Ask Your Doctor
Curated prompts to bring to your next appointment.
- 1.What is my exact platinum-free interval (PFI), and does it put me in a partially or highly sensitive category?
- 2.Based on my PFI, do you recommend trying a platinum-based chemotherapy again, or should we switch to non-platinum drugs?
- 3.Should my tumor be tested for folate receptor-alpha (FRα) or other biomarkers that might open up targeted treatment options like antibody-drug conjugates (ADCs)?
- 4.Are there any clinical trials for recurrent ovarian cancer that I am a good candidate for?
- 5.How will the side effects of this new treatment plan differ from the platinum chemotherapy I had previously?
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References
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This page explains ovarian cancer recurrence classifications for educational purposes only. Always consult your gynecologic oncologist for treatment recommendations.
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