What’s behind a six-fold jump in cure rate of stage 4 lung cancer?

The treatment performance of stage 4 lung cancer, one of the worst types of lung cancer, has been improving rapidly in recent years.

"Ten years ago, the five-year survival rate for stage 4 lung cancer was 5 percent. However, it is now up to 30 percent," said Kim In-ae, a professor of respiratory and allergy medicine at Konkuk University Medical Center, on the YouTube channel with the same as the hospital.

Professor Kim explained that there are three types of stage 4 lung cancer: when a small tumor is present in the lung but malignant pleural fluid (water in the lung) is nearby; when lung cancer that was only on one side of the bifurcated lung has spread to the other side; and when it has spread to the brain, bone, liver, or adrenal glands.

The secret to the recent improvement in the cure rate of stage 4 lung cancer is the emergence of the latest therapeutic drugs, such as targeted anticancer drugs and immuno-oncology drugs, according to Kim.

"There are many new treatments for stage 4 lung cancer," she said. “And there are cases where stage 4 lung cancer can survive for more than 10 years with targeted therapy."

Targeted anticancer drugs block the cell signaling system that targets cancer cells, and many new drugs are being developed, including EGFR (epidermal growth factor receptor) and ALK (anaplastic lymphoma kinase).

"Targeted anticancer drugs are mainly oral drugs, and they are very effective when administered," Professor Kim said.

The first generation of EGFR-targeted anticancer drugs, Iressa, and the second generation, Giotrif, are generally effective for 12 to 18 months, while the third generation of EGFR-targeted anticancer drugs, Tagrisso and Leclaza, have fewer side effects and are effective for longer.

ALK-targeted cancer drugs are even more effective than EGFR-targeted cancer drugs. ALK-targeted antitumor drugs that block the ALK signaling pathway include Xalkori, Alecensa, Alunbrig, and Lorviqua.

"ALK-targeted anticancer drugs are more effective than EGFR-targeted anticancer drugs and usually last up to 36 to 42 months," Professor Kim said. One of the lung cancer patients who received ALK-targeted therapy, Alecensa, was effective enough to shrink their lung cancer mass from for centimeters to less than one centimeter after three months, she noted.

The advantage of targeted cancer drugs is that they are highly effective and have few side effects. "Side effects are things like diarrhea and skin side effects," Kim said.

However, targeted cancer drugs also have a major drawback. Most of them develop resistance. "EGFR-targeted antitumor drugs become resistant after 18 months and need to be switched, and ALK-targeted antitumor drugs become resistant and usually need to be switched after three years, according to Professor Kim.

In addition to targeted agents, immuno-oncology is another newer treatment that has improved the outcomes of stage 4 lung cancer.

"Immuno-oncology drugs can kill cancer cells by increasing the body's immunity, and they are less toxic," Kim said. "The previously known cytotoxic chemotherapy has become much less toxic than before, and recently, the cure rate and survival rate of lung cancer have increased in combination with immuno-oncology drugs."

Immuno-oncology drugs block immunosuppressive proteins on cancer cells to boost the patient's immunity so that the patient's immune cells kill the cancer cells. "The patient's immune cells kill the cancer cells rather than injecting any toxic substances, so there are fewer side effects," Kim explained.

Immuno-oncology is highly effective, but it also has its drawbacks. When used as a standalone drug, it is effective in only one in five cases.

"Therefore, they are often combined with cytotoxic mainstream cancer treatment," Professor Kim said. "Less toxic and effective treatments are still being developed, so even if you have stage 4 lung cancer, it is better to be tested and treated with hope."