In too many cases, ovarian cancer does come back after initial treatment. While there are enormous emotional issues to handle, making good treatment decisions is, of course, crucial.
As part of initial treatment, most women get a so-called “platinum-based” chemotherapy. And this chemo is likely a part of the treatment for recurrence.
Read MoreUsing Platinum-Based Chemo For Recurrence
Eventually, many women with ovarian cancer become resistant to platinum-based treatment, some faster than others Nevertheless, doctors are likely to keep trying platinum until it stops working, which can happen after the first round of treatment, or even the fifth round. Oncologists will keep trying platinum-based drugs until they don't work anymore.What is “Platinum Resistance?”
If women recur within six months after completing platinum-based treatment, then they are deemed "Platinum Resistant," and will likely be given another type of treatment, at least initially. Six months is somewhat of an arbitrary mark, but that is the time frame generally used as a benchmark by doctors.Patients who go more than six months after Platinum-based treatment without a recurrence are deemed "Platinum Sensitive," which means they are responding well to platinum. Doctors are likely to continue platinum treatments in these patients.
Combining Platinum-Based Chemo with Taxol
Taxol is another drug that is usually given in initial treatment along with platinum-based drugs. In the case of a Platinum Resistant patient, a doctor might increase the dosage of Taxol, such as administering it weekly instead of every three weeks. Doctors may also use additional drugs such as Gemzar, Topotecan or Doxil with or without Avastin.
Adding Bevacizumab to Cut Off Blood Supply for Tumors
Any of these chemo drugs would likely be combined with a drug called Bevacizumab, known commercially as Avastin. This drug is a VEGF (Vascular Endothelial Growth Factor) inhibitor, which works by cutting off the growth of blood vessels to a tumor which helps reduce its growth. This process is known as anti-angiogenesis: blocking angiogenesis, the physiological process through which new blood vessels are formed out of ones already in existence.
Avastin is particularly helpful for women with high-risk cases of ovarian cancer. This includes:
- Widely metastatic cases that could have spread to the other areas, such as the liver and chest
- Cases where a tumor cannot be fully removed surgically
- Women with recurrent ovarian cancer
The drug has had a meaningful effect on recurrent cases that are both platinum sensitive (six months after platinum-based treatment) and platinum resistant (within six months of platinum-based treatment).
Women can continue using Avastin alone as maintenance after chemotherapy, as long as cancer doesn't recur and the woman tolerates the drug well.
Adding PARP Inhibitors to Treatment
The reason Platinum is so effective in ovarian cancer treatment is similar to the reason why many women respond to PARP inhibitors. Both treatments target a cell's ability to repair DNA, which prevents malignancies from repairing any DNA damage.
PARP inhibitors are becoming more widely used across the progression of ovarian cancer. They were first tested in women with recurrent ovarian cancer who also have the BRCA mutation. Women with the BRCA mutation have the greatest positive benefit from PARPs, though new evidence shows that using PARPs can extend life for many women.
Oncologists strongly recommend that women diagnosed with ovarian cancer undergo genetic testing to see if they carry a BRCA gene because it can help inform treatment decisions.
Summary of PARP Inhibitor Use For Recurrence:
- For women with ovarian cancer who have had a recurrence and responded to platinum-based chemotherapy, Lynparza, Zejula and another PARP inhibitor called Rubraca (rucaparib) are FDA approved for use as a maintenance therapy, regardless of whether a woman has a BRCA mutation or HRD.
- For some women who have had prior chemotherapy treatments, Rubraca, Zejula or Lynparza may also be options. These uses are based on factors such as number of prior therapies and BRCA mutation or HRD.
- The different PARP inhibitors do have some varying side effects, which women and their doctors need to evaluate carefully. It's important to ask your doctor if he or she has experience managing the side of effects for the various PARPs. Some of these considerations are explained here.
Are there other treatment options?
In 2023, a drug called Elahere (generic name mirvetuximab soravtansine) was given emergency approval by the Food and Drug Administration (FDA). Phase III clinical trials showed that the drug was effective at treating some patients who had become resistant to platinum-based chemotherapies.
The drug targets the folate receptor alpha (FRα) protein present on the tumor cell surface. The accelerated approval was based on a rigorous clinical trial called SORAYA, which showed effectiveness at suppressing cancer growth in at least one-third of patients.
The drug is expected to be given full approval in the U.S. after promising new data from another trial, MIRASOL, was released in May 2023.
The MIRASOL trial looked at how it performed compared to giving chemotherapy alone in patients with folate receptor alpha (FRα)-positive platinum-resistant ovarian cancer.
In the trial, more than one-third of patients (36%) receiving Elahere (who had previously been treated with bevacizumab) experienced improved progression-free survival (how long a patient goes without their disease worsening) and more than one-fourth (26%) experienced improved overall survival (how long the patient lives).
In another, smaller group of patients who had not previously been treated with bevacizumab, progressional free survival was 34% better and overall survival was 49% better than when patients received standard chemotherapy.
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