Combining two traditional methods, scientists can defeat cancer

The treatment of cancer by irradiation always has certain limitations, but researchers believe that new therapies can help increase the effectiveness of treatment and reduce the risk for patients.

In his final Federal message, US President Obama assigned the Vice President Joe Biden to lead an initiative on the National Cancer Center. The center was born in the hope of bringing the United States on the path to becoming " the first country to cure cancer once and for all. " The areas of research listed in this initiative are a local class. New cancer treatment is immunotherapy for cancer therapy and combination therapy.

Immunotherapy for cancer is a treatment by stimulating the immune system to targets and attacking cancer cells. Researchers believe that the combination therapy with traditional remedies may open up new possibilities for cancer treatment.

For example, irradiation is one of the most common and oldest measures used to treat cancer. But there are still limits on the amount of radiation that the human body can take, and it cannot kill all cancer cells. However, by combination therapy, irradiation can be combined with immunotherapy to form a " two-in-one punch " aimed at cancer cells.

Traditional irradiation methods cannot kill all cancer cells.

How does radiation kill cancer?

Most cancer patients incorporate some treatments such as surgery, chemotherapy and radiotherapy during their treatment. In particular, irradiation is used for about 50% of cancer patients. Unlike chemotherapy, which uses hundreds of different drugs to attack cancer cells in different ways, ionizing radiation is simply high-energy waves. No matter how much radiation is transmitted, the cells generally suffer from the same amount of radiation in similar ways.

Radiation can kill cancer cells directly by destroying their DNA, then activating different forms of cell degeneration, including the " suicide " of the cell. Because high-energy waves will also affect healthy cells surrounding cancer cells, a person can only receive a limited dose of radiation so as not to adversely affect healthy tissue. strong.

Cancer treatment with radiotherapy.

Over the years, radiotherapy has improved, allowing more radioactivity to focus on tumors and less harm to the surrounding normal cells. Today, patients are often treated with smaller, intervalally spaced doses, called fractional irradiation. This allows higher doses to be added to tumors, but less harmful side effects.

But even with these advances, there are still many cancer patients who cannot be treated with radiation. For example, cell suicide mechanisms require cellular activity to activate the "apoptosy progress" process.

Cancer cells can develop mutations in the gene that make them resistant to being destroyed by radiation, and then these cells can escape through the excretory pathway. And other cancer cells can survive because they only have to receive an insufficient amount of radiation to kill, because they are located deep inside the tumor.

Many cancer patients cannot be treated with radiation.

In some cases, radiation is not treatable at all. However, this therapy is still done to relieve pain or narrow the tumor before taking other treatments.

However, cancer cells, which can survive through irradiation, are not without effect. Recently, researchers have found that sudden irradiation of cancer cells can make them a better target for each of our immune systems, and that is the time for immunotherapy.

How does immunotherapy fight cancer?

In the early days of immunotherapy, people thought that therapies for mass destruction (such as radiotherapy and chemotherapy), would never be combined with an immunotherapy - which is intended to replicate. immune cells up.

However, researchers have shown that radiation can make tumor cells expose genes, which will enhance the activity of immune cells. This is interesting because many cancer cells can avoid detection by reducing gene expression, which can be recognized by the immune system and attack. This finding suggests that radiation can reverse this process and make cancer cells easier to recognize.

Photos taken through a color microscope show that T cells (pink) are attacking cancer cells (yellow).

For example, radiation may increase the expression of proteins on the surface of rectal tumor cells and prostate tumors, increasing survival and T cell killing mechanisms.

Radiation can also cause cancer cells to separate from the molecules, which are responsible for replenishing T cells for tumors, or stimulating the activity of other cancer-killing cells, called cells. Cells destroy from nature.

Many other immunostimulatory genes can also be prepared in radiation cancer cells, called immune stimulation modulation, in different types of cancer cells. So the old point of view is that radiation is completely weakening the immune system, and can not be used with new immunotherapy, is completely wrong. Therefore, from the perspective of immunology, radioactivity is still not being used properly.

Radiation supplements in these therapies make cancer cells a better target for T cells to be produced from immune treatments. And that's not the only potential benefit of using radiation and immunotherapy together.

A tray containing cancer cells on an electron microscope.

Attack cancer in other parts of the body

Radiation cannot target every tumor or every cancer cell in the body. It is also not feasible to radiate radiation to each and every tumor cell, when the disease has spread throughout the body.

That's where an effect is called " abscopal effect " (non-target effect). Absocal means " far from the target ", a biological term to describe an interesting phenomenon: sometimes treating a tumor by irradiating a part of the body, but eliminating and treating one The tumor is not treated at another location.

Many scientists believe that this effect is due to the activity of immune cells, triggered by radiation, which enhances the effectiveness of attack on untreated tumors. This can be seen by experimenting with cancer in experimental mice. However, it is also found in cancer patients in hospitals.

The Abscopal effect appears on the left leg when irradiating the tumor on the right leg of the experimental mouse.

In the past few years, there have been a series of high-level reports on abscopal reactions in patients with lung cancer, melanoma and other types of cancer. Abscopal reactions occur even in some malignant patients who receive only radiation to relieve pain. These patients have all been treated with immunotherapy in addition to radiation therapy.

The bad news is that we are still not sure exactly how to respond abscopal appropriately. The challenge is to accurately visualize the cause of the Abscopal effect so that it can reliably reconstruct it on combination therapy patients.

The remaining question is how good the radiation dose is to create this effect. The optimal time of irradiation is relative to the cancer immunotherapy. For specific types of cancer that will respond in this way and which immunotherapy is best to create this effect in the combined strategy.

Anyway, the good news is that radiotherapy has new assistants, which can make killing cancer cells more effective and safer for patients. It is cancer immunotherapy, which can reuse one of the oldest cancer treatments in new ways.