Platinum therapy is used to treat most cases of advanced ovarian cancer, fallopian tube cancer, and primary peritoneal cancer. How well the cancer responds — that is, how well these drugs work to kill the cancer cells — can tell doctors a lot about the cancer and help them decide on next steps.
Platinum therapy includes certain types of chemotherapy drugs that contain the chemical element platinum. The two most common platinum therapy options for ovarian cancer are cisplatin (Platinol) and carboplatin (Paraplatin).
Cisplatin and carboplatin work by damaging a cell’s DNA, which contains the cell’s genes. These drugs enter a cancer cell and bind different DNA strands together, which leads to gene mutations. The cell is then unable to produce new cancer cells and eventually dies.
Platinum therapy is most often given through an IV. In some cases, these drugs are also given as an intraperitoneal treatment — injected into the abdomen. This may be an option for people with stage 3 ovarian cancer that has spread outside the pelvis and who had most of their tumor removed during surgery.
People with advanced ovarian cancer typically receive platinum therapy after surgery. The medications are most often used with another type of chemotherapy called taxanes, such as paclitaxel (Taxol). Targeted therapies may be used at the same time. For people with stage 4 cancer that has spread to more distant locations, platinum drugs may also be used before surgery to try to shrink the tumors.
Many clinical trials — a type of research study — over the past couple of decades have shown that platinum therapy works well as a first-line or front-line therapy — the initial treatment someone receives for their cancer.
Platinum therapy doesn’t work for everyone. In particular, advanced-stage ovarian cancer can be difficult to treat. There are a couple of situations in which a person can have ongoing cancer despite platinum therapy. Relapsed or recurrent ovarian cancer seems to go away after it’s treated, but the cancer later returns. Resistant ovarian cancer can’t be adequately controlled by a particular treatment.
Response to treatment can be measured in a few ways. A complete response means that all signs of cancer disappear, but this doesn’t necessarily mean that the cancer won’t come back. A partial response means that a tumor shrinks or signs of cancer lessen but don’t fully go away.
According to the Gynecologic Cancer InterGroup, there are four categories of ovarian cancer, based on the disease’s response to platinum therapy:
Between 60 percent and 80 percent of cases of high-grade serous carcinoma, the most common type of epithelial ovarian cancer, at first respond well to platinum therapy. However, this cancer almost always will become resistant and recur after treatment. Other types of ovarian cancer that are most likely to be platinum-resistant include clear cell, mucinous, and low-grade serous carcinoma.
Ovarian cancer’s response to platinum therapy provides information about which treatments should be tried next. Doctors may recommend different treatment plans based on whether a case of ovarian cancer is sensitive, resistant, or refractory to platinum-based drugs.
If platinum therapy successfully kills enough cancer cells to cause signs of ovarian cancer to disappear and stay away for a long time, it’s a sign that the cells are at least partially sensitive to these drugs. Doctors will often recommend using the same chemotherapy drugs that were used the first time around because they’re likely to work again.
A medication like carboplatin often works very well to treat platinum-sensitive cancer, even after it returns. However, after a second treatment, the cancer will likely come back again and again, returning more quickly each time, until it is eventually classified as platinum-resistant.
If you have platinum-sensitive recurrent ovarian cancer, ask your doctor about the pros and cons of using another round of platinum therapy. The drugs may work well, but they also come with a lot of side effects that can reduce your quality of life.
Cancer of the ovary that returns soon after treatment with first-line chemotherapy may need a different treatment option. Overall, more than 4 in 5 people with advanced ovarian cancer will experience a relapse, often within two years of beginning treatment.
If you have resistant disease, your doctor might suggest giving platinum therapy another try but is more likely to recommend moving on to a different treatment plan. The next regimen often includes other chemotherapy drugs that do not contain platinum, such as:
These chemotherapies generally lead to similar outcomes. Your oncologist may recommend one of these medications based on factors like side effects, cost, convenience of accessing treatments, and which therapies you’ve received in the past.
Your doctor may also recommend targeted therapy or immunotherapy drugs such as bevacizumab (Avastin) and pembrolizumab (Keytruda) that zero in on cancer cells and prevent them from growing.
Targeted options include PARP inhibitors. In some ovarian cancer cells, a protein called poly (ADP-ribose) polymerase, or PARP, is required to repair damage to DNA. If your cancer cells have mutations to the BRCA genes, they require PARP to keep growing. PARP inhibitors can block PARP without affecting healthy cells.
PARP inhibitors currently available to treat ovarian cancer include:
PARP inhibitors are typically prescribed to be taken orally twice a day.
When first-line treatments don’t work at all and the cancer keeps growing, there is a higher chance that the cancer cells won’t respond to any drugs. This type of ovarian cancer is very difficult to treat.
If you have platinum-refractory ovarian cancer, work with your doctor to explore the benefits and risks of different treatment options. Your doctor may suggest seeing if some type of targeted therapy or chemotherapy regimen will control your cancer. The treatments that work best for you depend on your overall health and personal preferences.
Joining a clinical trial may be a good option for people with platinum-refractory disease. By participating in a study, you may be able to access a new type of drug or procedure that you couldn’t normally get through your oncologist. For example, researchers have identified many genes that affect whether cancer cells are sensitive or resistant to platinum, and recent clinical trials have looked into whether drugs that target these genes may help treat ovarian cancer.
Some people with platinum-refractory ovarian cancer may choose to not treat the cancer and instead rely on palliative or hospice care. Palliative care helps treat symptoms and meet the physical, emotional, and spiritual needs of a person with cancer and their loved ones. It can be used during any cancer stage, with or without other treatments that aim to cure the cancer. Hospice care, on the other hand, helps improve comfort and well-being at the end of a person’s life.
Making treatment decisions can be very complex. Many people find that they are happier with their cancer care when they engage in shared decision-making with their doctor. During this process, a person with cancer is informed about the potential benefits and risks of different treatment options, and the doctor takes into account the person’s preferences and values.
It’s always OK to ask for more information and keep asking questions when the information you’re given doesn’t make sense to you. You may want to do some reading about different treatment options on your own and write down questions to take to your medical appointments. For example, you could ask your doctor whether your cancer is sensitive or resistant to platinum therapy and what that means for your future treatments.
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Did your doctor discuss with you how your ovarian cancer responded to platinum therapy? Do you still have questions about what this means for your future treatment options? Share your experiences in the comments below, or start a conversation by posting on your Activities page.