Immunotherapy vs. Chemotherapy: They’re Not the Same

What Is Immunotherapy?

Immunotherapy is formulated to enhance the body’s immune system, empowering it to recognize and destroy cancer cells.

Normally, the immune system can detect and eliminate “bad” cells – cancerous or otherwise – that pose threats to health. However, cancer cells can “hide” and escape detection by the immune system. Immunotherapy uses proteins and other substances made by the body or in a lab to strengthen the immune system and give it the boost it needs to find and destroy cancer cells.

The various types of immunotherapy include:

• Monoclonal antibodies, man-made proteins that mimic the body’s natural antibodies to target specific proteins found only in cancer cells.
• Checkpoint inhibitors, which block the proteins, or checkpoints, that prevent certain cancer-fighting white blood cells (called “T cells”) from attacking cancerous cells. This blocking, or inhibition, enables the T cells ton start attacking the cancer.
• T-cell therapy. T cells are extracted intravenously (through a needle inserted into a vein), multiplied and re-engineered in a laboratory, and then infused back into the body to help the immune system find and kill certain cancers.
• Vaccines. Unlike vaccines administered to prevent infections, these vaccines trigger the immune system to attack cancer cells.

Immunotherapy agents can be administered:

• Intravenously,
• orally with a pill or capsule,
• topically with a skin cream (used to treat some skin cancers),
• or intravesically (directly into the bladder using a catheter, an approach used for some bladder cancers). 

When determining the most suitable type of immunotherapy for each case, the medical team will review the patient’s medical history, cancer type, and cancer stage.

What Is Chemotherapy?

Chemotherapy, or chemo, is a commonly employed cancer treatment that uses powerful medications to attack and kill cancer cells or prevent them from spreading. By killing cells and reducing the size of tumors, these drugs may also alleviate pain and other symptoms. Chemotherapy may be administered orally or intravenously. Topical chemotherapy also is used for some skin cancers.

Oncologists in some cases use chemo to shrink tumors before the patient receives other treatments such as surgery or radiation. This is known as “neoadjuvant chemotherapy.”

There are different types of chemotherapy drugs. They include:

• Alkylating agents, which damage the DNA of cancer cells and prevent them from reproducing.
• These are alkylating agents that can travel into the brain through the blood-brain barrier to help treat some brain cancers.
• Antimetabolites, which interfere with the DNA and RNA building blocks in cancer cells to stop them from reproducing.
• Anti-tumor antibiotics, which mutate the DNA inside cancer cells to prevent them from growing and multiplying.
• Topoisomerase inhibitors. These agents prevent cancer cells from replicating by interfering with enzymes that attempt to separate and copy DNA strands.
• Mitotic inhibitors, which are formulated to stop cancer cells from dividing and forming new cells.

When chemotherapy is indicated, the medical team will determine which chemo type, dose, and treatment frequency is most suitable for the type and stage of the patient’s cancer.

Differences Between Immunotherapy vs. Chemotherapy

While both immunotherapy and chemotherapy have strong evidence supporting their use, several key factors determine which treatment is more likely to be effective for a given patient. These factors include:

Cancer Type

Chemotherapy, widely used since the 1940s, is considered standard treatment for many different cancer types, including:

• Brain cancer
• Breast cancer
• Lung cancer
• Ovarian cancer
• Leukemias
• Lymphomas
• Hodgkin disease
• Multiple myelomas
• Sarcomas

Immunotherapy is an innovative treatment that has become more widely available over the last 10 years. Studies have shown immunotherapy to be effective in targeting tumor growth in patients with aggressive cancers such as leukemia, lymphoma, kidney cancer, lung cancer, skin cancer, and prostate cancer. Immunotherapies are continuously being researched for use in more types of cancer, and each year the U.S. Food and Drug Administration approves new immunotherapy drugs and new uses for existing agents.

Method

Chemotherapy targets cancer cells directly, preventing them from growing and spreading. Chemo usually is a systemic treatment, meaning it travels through the bloodstream and throughout the body.

Immunotherapy “teaches” the immune system to find and fight cancerous cells that had been eluding detection. Immunotherapy has been shown to be effective in treating certain cancers resistant to chemotherapy and radiation.

Length of Treatment Effectiveness

Chemotherapy treatment is an effective treatment option and generally starts to work on shrinking a tumor almost immediately. However, this effectiveness only lasts as long as the medicines remain in the body. That is why specialists administer chemo in cycles, so the patient can continue receiving the treatment benefits.

Immunotherapy is also effective, but it generally takes more time to start seeing results with this approach. Immunotherapy, however, can work for an extended time, even after the therapy has stopped. The immune system has a “memory” that allows it to recognize and remember the cancer cells, allowing it to continue fighting any new cancer cells that may develop.

Side Effects

Because chemotherapy is a systemic treatment, it affects both cancerous and non-cancerous cells as the drugs travel through the body. The damage to the non-cancerous cells can lead to side effects such as hair loss, nausea and vomiting, diarrhea, and fatigue, among others. These side effects are generally temporary and can range from mild to severe, depending on the chemo dose and schedule.

Because of these side effects, chemo usually is delivered on a tailored schedule, so that the patient can recover between doses.

Immunotherapy is more targeted, so it is less likely than chemo to affect non-cancerous cells. Some patients, however, may develop side effects from an overstimulated or overactivated immune system. Some adverse effects, such as nausea and flu-like symptoms, can be minor, but more severe effects such as infections, inflammation, or organ failure are possible. The medical team will monitor the patient closely for reactions to ensure safety during and after immunotherapy treatment.

Frequently Asked Questions About Chemotherapy and Immunotherapy

Does chemotherapy or immunotherapy work faster?

In general, chemotherapy works faster because the tumors are targeted directly and can start shrinking immediately. Immunotherapy treatments usually take longer to start working, as the immune system needs an extra “push” to attack the tumors.

What is “pseudo-progression” in immunotherapy?

Occasionally, when immunotherapy is started, tumors can appear to grow because of the intrusion of immune cells into the tumors. It does not necessarily mean the cancerous cells in the tumor are increasing in size, or that the treatment is not working.

How do you know if chemotherapy and immunotherapy are working?

To determine if either treatment is effective, oncologists use blood tests and imaging scans, such as MRI (magnetic resonance imaging) and CT (computed tomography). Blood tests show the levels of certain hormones, enzymes, proteins, or biomarkers that can provide important indications of response to treatment. Scans enable physicians to see if tumors have shrunk, remained the same, or spread.

How long does immunotherapy treatment take?

Oncologists and hematologists usually give immunotherapy treatments in cycles. Each cycle can last around 2 to 3 weeks. Patients generally need several cycles, as it takes time for the immune system to react. That means results may not be apparent for several months.

Does immunotherapy always work?

While immunotherapy can treat certain aggressive cancers that are resistant to other treatment, it is not always effective for all cancer types. And, as with all treatments, there is no guarantee that it will be effective for a specific patient, although physicians are able to draw on extensive data to determine which types of patients are likely to benefit from immunotherapy.

Get World-Class Cancer Treatment at RCCA

Regional Cancer Care Associates (RCCA) offers chemotherapy, immunotherapy, and other cutting-edge, evidence-based cancer treatments at 22 community-based locations throughout New Jersey, Connecticut, Maryland, and the Washington, DC area. RCCA oncologists and hematologists see more than 26,000 new patients each year and provide care to more than 245,000 established patients, collaborating closely with their patients’ other physicians.

In addition, RCCA offers patients access to clinical trials, studies that may connect qualifying patients with another, potentially effective treatment option. If you’re grappling with a cancer diagnosis, request an appointment today to learn about your treatment options.