Breakthroughs in cancer treatment

With the immunotherapy drug dostarlimab, tumor-targeted therapy, or an mRNA vaccine, the world is slowly gaining fruit in the fight against cancer.

Cancer treatment is a long, slow and expensive process. After decades of research, scientists have made some breakthroughs in treatment methods, but the changes have not been significant. Most oncologists are reticent about new works. They will always defuse unrealistic expectations by asserting: “There is no elixir (for cancer) and there never will be in the future”.

However, more than 50 years after the West first announced its entry into the “war on cancer”, the world is slowly reaping the rewards.

Survival rates for diseases such as breast cancer, prostate cancer and skin cancer are unprecedented. Patients have a longer prognosis. With each published report, scientists better understand what barriers need to be overcome to properly conquer the disease.

Experts say there is still a long way to go, but thanks to the continuous advances of modern science, people are gradually overcoming the complex disease.

In recent months, the world has paid attention to achievements such as: vaccines that train the immune system to destroy pancreatic cancer; Immunotherapy detects mutant cells in rectal cancer patients; drugs that slow the growth of cancer cells were once thought to be untreatable.

In general, expectations focus on approaches that are increasingly accurate and tailored to each specific audience.

“We started to segment patients into different groups that were tailored to different treatments rather than having one therapy for everyone,” said Dr. Naureen Starling, consultant oncologist at The Hospital Royal Marsden Institute, said.

Experts understand that no two cancers are the same. In each person, tumor cells are driven by a series of distinct mutations that hide or evade the immune system in their own way.

Scientists have been researching cancer treatments for decades. Image: Roche

One of the recent achievements is experimental immunotherapy drug named dostarlimab. The drug helped cure rectal cancer for 12 volunteers in a 6-month trial.

Dostarlimab does not work by directly attacking the cancerous tumor itself, but prompts the patient’s immune system to do so.

Normally, T cells (immune cells) are responsible for finding and controlling foreign pathogens. They contain two types of proteins: one that helps trigger an immune response, the other that limits immunity. These are called checkpoint proteins.

Some cancer cells make high amounts of type two proteins. They inactivate T cells before the tumor disappears. In other words, cancer cells cause the patient’s immune system to stagnate.

The drug dostarlimab blocks type two checkpoint proteins, which block the effect of cancer cells on the immune system. When the immune system is active again, the T cells can find and attack the cancer cells.

However, the drug is only suitable for patients with impaired function of the DNA pairing error repair (MMR) system. These patients have certain genetic mutations that cause the repair system to fail when it comes to matching DNA in the cell. Uncorrected cells often have many genetic mutations, which can lead to cancer.

In addition to Dostarlimab, there are thousands of clinical studies aimed at harnessing the power of the immune system to attack the weak points of melanoma. MMR-induced mutations are present in 4% of colon cancer patients, 4% of gastric cancer patients, and 2% of pancreatic cancer cases. The effectiveness of the drug depends on the location of the tumor and how the immune system acts on that area.

Another tool to help treat cancer is “targeted therapy”, focusing on the tumor itself and the cancer cells instead of the immune system. The therapy attacks the cell’s switches and the proteins that divide and copy the problem, causing the tumor to grow uncontrollably.

A new drug that uses this mechanism, called trastuzumab deruxtecan, was presented at a meeting of the American Society of Clinical Oncology. In 373 patients taking the drug in the clinical trial, tumors stopped growing for about 10 months.

For patients with metastatic breast cancer that is progressing despite chemotherapy, trastuzumab deruxtecan attacks cancer cells directly. It has laser-like accuracy, slowing tumor growth and prolonging life to unprecedented levels.

The drug targets HER2, a gene that promotes breast cancer growth. This is a mutation commonly found in breast cancer and many other diseases. Patients with high HER2 levels can be effectively treated with medication. However, in patients with only a few HER2 cells, these drugs do not work. Trastuzumab deruxtecan contains an antibody that seeks and destroys HER2 before it travels to nearby cancer cells.

Drug effects go beyond breast cancer. It opens the door to targeting molecular abnormalities in tumor cells in general, which are sparse in patients.

The cancer drug trastuzumab deruxtecan.  Photo: Daiichi Sankyo

The cancer drug trastuzumab deruxtecan. Image: Daiichi Sankyo

Another hope of scientists in the treatment and prevention of cancer is vaccines using mRNA technology, Similar to the Covid-19 vaccine. The vaccine trains the immune system to destroy pancreatic cancer cells.

In a study published in the American Society of Clinical Oncology, half of the patients who received the vaccine were disease-free after 18 months.

Pancreatic cancer is one of the deadliest cancers, with 90% of patients dying within two years of being diagnosed. Survival rates and treatment breakthroughs have not improved after decades.

Pancreatic cancer vaccine opens new hope. It is tailored to each patient with the genetic code for the mRNA found in their own tumor. Once injected, the vaccine instructs the body to make proteins that are identical to those on the tumor’s surface, triggering an immune response.

After being destroyed, the body forms an immune memory. The remaining cancer cells in the blood will continue to be destroyed by the T cells in the future, preventing the cancer from coming back. Eight of the 16 vaccinated patients did not develop cancer during the clinical trial.

Still, according to Dr Juanita Lopez, a clinical researcher at Cancer Research London, these “high-flowering individual” treatment strategies are often complex, expensive and time-consuming. It took experts about four weeks to create a vaccine for just one patient.

It will take another 10 to 20 years to determine whether the vaccine is as protective as the HPV shot against cervical cancer.

Although there is no “silver bullet” to definitively treat cancer, scientists still believe that it is possible to gradually remove the death sentence for patients with increasingly sophisticated and accurate methods.

“Like the first time when chemotherapy started to be introduced into the application, this could be the beginning of a big change where we move to the next phase,” said Dr. Sam Godfrey, Chief Information Officer senior research news at Cancer Research UK, says.

Thuc Linh (Follow SCMP)


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