Advanced cancer therapies represent a significant evolution from historical treatments that took a broad approach, targeting any rapidly dividing cell. While this destroyed cancer cells, it also damaged healthy tissues like hair follicles and bone marrow. This “one size fits all” model is being replaced by a new paradigm of personalization and precision. The core principle of modern therapy is to tailor treatment to the specific molecular and genetic drivers of an individual’s cancer. By identifying what makes a cancer cell unique, these treatments can attack the tumor with greater accuracy, aiming to maximize effectiveness while minimizing harm to the rest of the body.
Harnessing the Immune System
A powerful strategy in modern cancer care involves using the body’s own immune system to fight the disease. The immune system constantly patrols the body for abnormal cells, and tumor-infiltrating lymphocytes (TILs) found near tumors are a sign it recognizes cancer and is trying to respond. Cancer cells, however, can develop methods to evade this attack, such as producing proteins that act as a “stop sign” for immune cells. Immunotherapy is a class of treatments designed to counteract these tactics by boosting or retraining the immune system to be more effective.
A widely used form of immunotherapy is a class of drugs called checkpoint inhibitors. Immune cells have natural “brakes,” or checkpoints, that prevent them from becoming overactive. Some cancer cells exploit this by displaying proteins that engage these checkpoints, tricking the immune system into ignoring them. Checkpoint inhibitor drugs block this interaction, “releasing the brakes” on immune cells and allowing them to launch a more powerful attack.
Another approach is CAR T-cell therapy, which creates a “living drug.” This treatment involves drawing a patient’s T-cells and genetically engineering them in a lab to produce special receptors called chimeric antigen receptors (CARs). These new receptors are designed to recognize and bind to specific proteins, or antigens, on the surface of the patient’s cancer cells.
Once engineered, these modified T-cells are multiplied into the millions and infused back into the patient. Equipped with their new targeting system, the CAR T-cells can hunt down and kill cancer cells throughout the body. This therapy turns the patient’s own cells into a precision-guided weapon against their specific cancer.
Therapeutic cancer vaccines also stimulate a targeted immune response. Unlike preventative vaccines, these are given to people who already have cancer. The vaccines introduce cancer-specific antigens into the body to provoke a robust immune reaction. This process helps the immune system learn to recognize these antigens as foreign, prompting it to destroy tumor cells that display them.
Targeted Molecular Therapies
Targeted molecular therapies are designed to interfere with specific molecules essential for a tumor’s growth and survival, based on its unique genetic profile. The effectiveness of this approach hinges on identifying the right “target” within the cancer cells through biomarker testing. This analysis of a tumor sample looks for specific gene mutations or proteins to match the right patient to the right drug.
An analogy for how these therapies work is a “lock and key” mechanism, where the molecular target is the lock and the drug is the key. For instance, some non-small cell lung cancers are driven by a mutation in the EGFR gene. Drugs known as EGFR inhibitors block this faulty receptor, shutting down the signal that tells cancer cells to grow and divide.
Some breast cancers have an overabundance of a protein called HER2 on their cell surface, which promotes aggressive growth. Targeted drugs have been developed to seek out and attach to the HER2 protein. This action can block the protein from sending growth signals and can also flag the cancer cell for destruction by the immune system.
These therapies work by blocking chemical signals that stimulate cancer cell growth, changing proteins within cancer cells to cause them to die, or triggering the immune system to destroy them. Their selective action often spares healthy cells, which can lead to different and sometimes less severe side effects compared to traditional chemotherapy.
Innovations in Radiation Oncology
Radiation therapy has undergone significant technological advancements to improve its precision. Modern techniques aim to deliver a potent, focused dose of radiation directly to the tumor while minimizing exposure and side effects to surrounding healthy tissue.
One innovation is proton therapy. Traditional radiation uses X-ray beams that deposit energy along their entire path through the body. Proton beams can be controlled to stop and release the bulk of their energy at the precise depth of the tumor, with almost no radiation dose delivered to the tissue behind it. This is advantageous when treating tumors near sensitive structures like the brain or spinal cord.
Stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT) are techniques that deliver high doses of radiation to a specific area. SRS is used for tumors in the brain and spine, while SBRT is used for tumors in other parts of the body. These procedures use advanced imaging to target the tumor with sub-millimeter accuracy, allowing a full course of radiation to be delivered in just one to five sessions.
A newer treatment, radiopharmaceuticals, combines a radioactive substance with a cell-targeting molecule. This drug travels through the bloodstream to seek out and bind to specific proteins on cancer cells. Once attached, the radioactive component delivers a localized dose of radiation, killing the cancer cells from the inside out.
The Role of Clinical Trials in Accessing New Therapies
Clinical trials are research studies that involve patients to determine if a new therapy is safe, effective, and better than existing options. For many patients with advanced or rare cancers, a clinical trial may offer access to cutting-edge therapies before they become widely available.
The process is structured in phases, each designed to answer different questions. Phase 1 trials are the earliest stage, focusing on safety and determining the best dose and administration method in a small group of patients. Phase 2 trials expand to a larger group to evaluate effectiveness against a specific cancer and further assess safety.
If a treatment shows promise, it moves to a Phase 3 trial, which involves hundreds or thousands of patients. The goal is to compare the new treatment against the current standard of care to confirm its effectiveness and monitor side effects. The results of these trials are used by regulatory agencies, like the FDA, to decide whether to approve a new therapy.
A common concern for patients is receiving a placebo. In cancer research, a patient rarely receives a placebo alone if an effective standard treatment exists. Participants will receive either the new treatment or the best available standard therapy. A placebo might only be used when no standard treatment exists or in combination with an active drug.
Finding a suitable clinical trial can be done through several resources. The National Cancer Institute (NCI) maintains a searchable database of clinical trials. Patient advocacy organizations, academic medical centers, and a patient’s own oncology team are also valuable sources of information.