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Immunotherapy emerges as a breakthrough in cancer care
After decades of development, treatments that harness the body's immune system to combat cancer are transforming patient outcomes, offering hope without the harsh side effects of traditional therapies.
A patient's remarkable recovery
Maureen Sideris, a 71-year-old New York resident, faced a second cancer diagnosis in 2022-this time, oesophageal cancer. Instead of surgery, chemotherapy, or radiation, she enrolled in a clinical trial at Memorial Sloan Kettering Cancer Center. Over four months, she received infusions of dostarlimab, an immunotherapy drug. By the end of the treatment, her tumor had vanished, leaving her with only manageable fatigue as a side effect.
"It's unbelievable. It's almost like science fiction."
Maureen Sideris, cancer survivor
How immunotherapy works
The human immune system naturally detects and eliminates abnormal cells, including cancerous ones. However, some tumors evade detection by disguising themselves as healthy tissue. Immunotherapy aims to unmask these cells, enabling the immune system to target and destroy them.
Two leading approaches dominate the field: CAR T-cell therapy and immune checkpoint inhibitors. CAR T-cell therapy involves modifying a patient's T cells in a lab to attack cancer cells, primarily used for blood cancers. Immune checkpoint inhibitors, meanwhile, block proteins that cancer cells use to deactivate T cells, allowing the immune system to recognize and attack tumors. The scientists behind this innovation were awarded the Nobel Prize in 2018.
Challenges and limitations
Despite its promise, immunotherapy has hurdles. CAR T-cell therapy struggles with solid tumors, which account for over 90% of new cancer cases, and remains costly and labor-intensive. Immune checkpoint inhibitors, while effective, can trigger severe side effects, including inflammation of organs like the liver, heart, and kidneys, as the immune system may attack healthy tissue.
Response rates also vary. Only 20% to 40% of patients benefit from immunotherapy, leaving many exposed to side effects without significant gains. Researchers are exploring ways to improve efficacy, including dietary adjustments, timing of treatments, and combining immunotherapy with other therapies like radiation or ultrasound.
Personalized medicine and future directions
Cancer is not a single disease but a collection of over 200 distinct conditions, each requiring tailored approaches. Personalized medicine is gaining traction, with researchers matching patients to treatments based on genetic profiles. For example, tumors with specific genetic signatures respond well to immune checkpoint inhibitors like dostarlimab. In trials, this approach eradicated tumors in 84 of 103 patients with rectal, oesophageal, bladder, and stomach cancers.
Cancer vaccines represent another frontier. Unlike traditional vaccines that prevent disease, these train the immune system to target existing tumors. Early trials show promise, with personalized vaccines triggering anti-cancer responses in kidney cancer and melanoma patients.
Hope and hurdles ahead
While immunotherapy is saving lives, challenges remain. Many promising treatments fail in early clinical trials, and not all patients respond. Luis Diaz, head of solid tumor oncology at Memorial Sloan Kettering, emphasizes the need for broader solutions: "We have to move from Medieval times to modern times. To remove your rectum or your stomach or bladder-we've got to do better than that."
For now, immunotherapy offers a lifeline to those who respond. Sideris, reflecting on her experience, believes the field is moving in the right direction. "One of the doctors told me that within 10 years, doing any kind of chemo and radiation is going to be like bloodletting-so old-fashioned."
"People are living, and living with good quality lives. We're talking about cures."
Jennifer Wargo, professor of surgical oncology, MD Anderson Cancer Center
