How Are Heart and Hearing Protected in Osteosarcoma Chemo?

When a child is treated for osteosarcoma, doctors use intense chemotherapy regimens to kill cancer cells, but these powerful drugs can also affect healthy organs. To mitigate these risks, the care team takes active, highly structured steps to protect your child’s heart, hearing, and kidneys. They use specific protective medicines and protocols to reduce the risk of doxorubicin-related heart injury, conduct regular audiograms (hearing tests) to catch cisplatin-related hearing loss early, and closely monitor kidney function and urine flow to ensure chemotherapy clears the body safely.

Reducing Heart Risk: Dexrazoxane

One of the key drugs used to treat osteosarcoma is doxorubicin, an anthracycline that is highly effective but carries a risk of causing long-term damage to the heart muscle (cardiotoxicity). As the cumulative dose (the total amount of the drug given over all treatments) increases, so does the risk to the heart. To help combat this, doctors may administer a cardioprotectant drug called dexrazoxane ^[1][2].

Given through an IV immediately before a doxorubicin dose, dexrazoxane is designed to reduce the risk of anthracycline-related myocardial injury and a reduction in the heart’s pumping ability ^[3][4]. While it does not guarantee complete protection, research in pediatric cancer shows that dexrazoxane reduces early and long-term heart injury without compromising the tumor-killing power of the chemotherapy ^[5][1].

Alongside this protective medication, your child’s care team will perform a baseline echocardiogram (an ultrasound of the heart) before treatment begins, followed by serial tests during treatment and long after treatment ends to monitor heart function ^[6]. Families should promptly report symptoms like chest pain, fainting, unusual shortness of breath, or swelling to their care team.

Monitoring and Protecting Hearing

Another frontline osteosarcoma drug, cisplatin, can cause hearing loss (ototoxicity), particularly affecting high-frequency sounds first. To manage this risk, children undergo a baseline audiogram before starting cisplatin, followed by repeat hearing tests throughout their treatment and into survivorship ^[7][8]. For young children who cannot reliably complete behavioral listening tests, audiologists can use objective measurements like otoacoustic emissions or auditory brainstem response testing ^[9].

Catching hearing loss early allows the medical team to discuss whether any treatment adjustments are appropriate, though changing the duration of a cisplatin infusion is not recommended to reduce hearing damage ^[10]. In some cases of non-metastatic disease (cancer that has not spread to distant sites), a protective drug called sodium thiosulfate may be considered ^[10][11]. This drug is heavily protocol-dependent and must be given at a specific time after cisplatin. Because hearing loss can develop or worsen after treatment ends, long-term monitoring is important. If hearing loss does occur, specialists can provide hearing aids, speech-language support, and school accommodations ^[12].

Guarding the Kidneys to Clear Chemotherapy

Your child’s kidneys play a crucial role in safely removing chemotherapy drugs from the body. Both cisplatin and high-dose methotrexate (HD-MTX) can stress the kidneys, but they require different protective strategies:

• For Cisplatin: The team administers large volumes of IV fluids (hydration) and replaces magnesium, an electrolyte that can be depleted by the drug, to help prevent kidney injury ^[13][7].
• For High-Dose Methotrexate: If methotrexate is not cleared by the kidneys on schedule (delayed clearance), it can lead to severe, widespread toxicity ^[14]. To maintain a safe urine flow and support drug clearance, the team uses aggressive IV hydration and urine alkalinization (adding medications to make the urine less acidic) ^[15]. They closely monitor creatinine (a blood marker of kidney function), urine output, urine pH, and specific methotrexate blood levels timed to the protocol ^[16].

Following HD-MTX, patients receive leucovorin, a crucial rescue medicine timed precisely by the oncology team to protect healthy cells ^[15]. If blood tests show methotrexate is clearing too slowly, the team will urgently escalate rescue measures. For cases of severe delayed clearance with kidney injury, a specialized medication called glucarpidase may be used to rapidly break down the methotrexate in the blood ^[17].

Medication Safety Alert: Never give your child over-the-counter medicines (especially NSAIDs like ibuprofen) or new prescription drugs without checking with your oncology team first. These can interact with the chemotherapy, worsen kidney function, and cause dangerous delays in clearing methotrexate from the body ^[15].