Carboplatin

Mesothelioma Chemotherapy with Carboplatin

The standard of care for treating pleural mesothelioma and peritoneal mesothelioma includes pemetrexed (brand name Alimta) and Cisplatin (brand name Platinol). However, carboplatin, also known by the brand name Paraplatin, is a member of the same drug class as cisplatin and works in the same way. It may therefore be used in place of cisplatin for mesothelioma treatment.

Both drugs are alkylating agents, meaning the platinum compounds in them damage the DNA of cancer cells to induce apoptosis (cell death). These drugs affect both normal and cancerous cells, but because cancer cells divide more rapidly, they are more affected by the damaged DNA.

Carboplatin Side Effects

Because carboplatin’s damage cannot be limited to cancer cells, patients should expect side effects including:

• Thinning hair
• Loss of appetite
• Stomach pain
• Diarrhea
• Constipation
• Nausea and vomiting
• Changes in taste

These side effects usually disappear after treatment has been completed.

There are more severe side effects, however, which require immediate medical attention:

• Allergic reactions such as rash, hives, difficulty breathing, tightness in the chest, or swelling of the face, lips, or tongue
• Change in the amount of urine produced or dark-colored urine
• Hearing loss or ringing in the ears
• Fever, chills, or sore throat
• Redness, swelling, or pain at the injection site
• Numbness or tingling in the hands or feet
• Irritation or sores in the mouth
• Persistent tiredness or weakness
• Unusual bruising or bleeding
• Vision loss or blurred vision
• Yellowing of the skin or eyes

The stem cells contained in bone marrow are also rapid dividers, meaning carboplatin may deal heavy damage to them at the same time it is fighting the cancerous cells. This can lead to myelosuppression, or suppression of bone marrow function. When the bone marrow cannot operate at capacity, the number of red blood cells, white blood cells, and platelets in a patient’s blood will reduce.

With fewer red blood cells to carry oxygen throughout the body, a patient is likely to feel fatigued and have low amounts of energy. The decrease in white cell count can cause an increased risk of infection, meaning minor problems the body could have fought off in the past may require hospital admission and/or treatment via antibiotics. Thankfully, blood cell levels typically return to normal after the cessation of treatment.

Differences Between Carboplatin and Cisplatin

As drugs in the same class, carboplatin and cisplatin work in very similar ways. Both cause interstrand DNA cross-links (see the cisplatin page for more information), but carboplatin simply works more slowly than cisplatin. Aquation, the process that allows the drug to activate, takes longer in carboplatin, which is why a higher dose is needed to have the same effects.

Depending on the type of cancer, carboplatin is sometimes less effective than cisplatin. However, it does have the benefit of causing fewer side effects, which can be important for patients who are already in poor health.

A comparison of patients who used the drugs found:

• The side effects of nausea and vomiting are experienced by nearly 100 percent of all patients treated with cisplatin, but by only 35 percent of those receiving carboplatin.
• Carboplatin, except at very high doses, causes very little if any kidney damage, whereas 1 in 3 patients will experience kidney damage after a single dose of cisplatin.
• In 85 percent of all patients receiving a dose over 300 mg/m2 of cisplatin, side effects can include hearing loss, numbness, tingling, and burning sensations in the arms and legs, nerve damage to the heart, stomach, intestines, bladder or genitals, seizures, and changes in brain function. In nearly half, the damage is irreversible. In carboplatin, the incidence of these side effects is less than 5 percent.

Substituting Carboplatin for Cisplatin

For patients who are not able to take cisplatin due to existing health issues, carboplatin may be substituted. Patient conditions that may lead a doctor to recommend this approach include:

• Hearing loss
• Kidney insufficiency (creatinine clearance < 60 ml/min)
• Class III or IV congestive heart failure

Carboplatin-based therapy is considered inferior to cisplatin therapy, but when the latter cannot be used, adding carboplatin to the treatment can make it more effective than a single-agent regimen. It is frequently used as an adjuvant (secondary) therapy after surgery.