Hepatocellular carcinoma (HCC) is a lethal disease that is detected early in only a small number of patients, despite clinical recommendations for screening for hepatocellular carcinoma in high-risk groups for early detection and treatment.
For most patients with mid- to late-stage liver cancer at diagnosis, treatment options include radiofrequency ablation or microwave ablation, catheterization (transarterial chemoembolization or radioembolization), systemic chemotherapy, and oral treatment with new targeted agents. These treatments mostly have limitations, and people are also looking to local radiotherapy.
The word “radiotherapy” is not new to anyone, but many people may not understand what kind of treatment radiotherapy is.
This is the first time I’ve seen the word “radiotherapy,” but many people don’t know what kind of treatment it is. Radiotherapy is the use of radiation to kill cancerous tissue, and because the radiation is not visible to the naked eye, it is known as the “invisible scalpel.
In recent years, with rapid advances in technology, local radiotherapy has brought new hope to patients with advanced liver cancer, including stereotactic body radiotherapy (SRBT) and yttrium 90 micron selective internal radiation therapy (SIRT). internal radiation therapy (SIRT).
What is stereotactic radiation therapy?
Stereotactic radiation therapy (SRBT) uses imaging equipment to capture images of the tumor and surrounding normal tissues to precisely locate the tumor in the body and then deliver a high dose of radiation to cause focal destruction of the tumor, thereby minimizing damage to normal tissues and achieving treatment goals.
To put it bluntly, SBRT is the use of imaging equipment to precisely locate and locally deliver the maximum amount of radiation to kill cancerous tissue without damaging normal tissue.
What is yttrium particle selective internal radiation therapy?
Yttrium (Y90) particle-selective internal radiation therapy (SIRT) is a new approach to targeted high-dose radiotherapy of liver tumors through the hepatic vasculature.
The liver is fed by two vessels (hepatic artery and portal vein), and the blood supply required for tumor growth comes primarily from the hepatic artery, so yttrium microparticles act primarily through the hepatic artery. Healthy liver tissue receives blood through the portal vein, and little healthy tissue is damaged during the treatment process.
Yttrium particles are tiny spheres with radioactive material, and yttrium is a more desirable nuclide for radiation therapy.
Yttrium (Y90) emits only β-rays, and unlike the γ-rays used in other radiotherapy treatments, the β-rays radiate to tissue at a distance of less than 1 cm, averaging 0.25 cm. That is, yttrium microspheres, when implanted in the body, are highly lethal to tumor cells within 0.25 cm of the surrounding area, with diminishing impact beyond that range, and therefore less harmful to normal cells adjacent to the tumor. The tumor cells in the vicinity of the tumor are relatively less harmful.
The principle of SIRT treatment is actually to kill cancer tissue precisely by implanting yttrium 90 microparticles along the hepatic artery.
The surprise of individualized SRBT treatment: safe and effective
Results from a recent study showed that individualized SRBT treatment of hepatocellular carcinoma patients with preexisting liver dysfunction, based on direct biomarkers of liver function, resulted in 99% and 95% local control remission rates at 1 and 2 years, respectively, and was well tolerated by patients.
The above studies demonstrate that individualized SRBT based on direct biomarkers of liver function can provide both effective local tumor control and a high degree of safety.
Individualized stereotactic radiation therapy may represent a new treatment paradigm, with the greatest highlight being that the SRBT dose is determined based on the individual patient and tolerance to treatment, and is not a blanket treatment.
SIRT approximates the efficacy of new targeted drugs
Sorafenib, an oral targeted agent for the treatment of advanced hepatocellular carcinoma, significantly improves survival time for patients with advanced hepatocellular carcinoma by 2 to 3 months and is often used clinically as a last line of hope for patients with advanced hepatocellular carcinoma.
However, various adverse effects of sorafenib (such as diarrhea, fatigue, and skin changes on the hands and feet) have forced patients to stop taking the drug or reduce the dose.
So when comparing SIRT to sorafenib, both used to treat patients with advanced unresectable liver cancer, what are the differences in efficacy?
The study showed that patients with hepatocellular carcinoma with intrahepatic metastases or who had received hepatic artery embolization chemotherapy that was not effective had a median survival (survival in 50% of patients) of 8 months with SIRT and 9.9 months with oral sorafenib, with no significant difference in years of survival.
In terms of safety, 77% of patients treated with SIRT experienced at least one treatment-related adverse event, compared with a high rate of 82% in patients taking oral sorafenib. These treatment-related adverse events included malaise, decreased liver function, diarrhea, blood-related changes, abdominal pain, elevated creatinine, and skin reactions in the hands and feet, with a lower incidence of adverse events in patients who had SIRT therapy.
There was no significant difference between the two treatments in terms of improved survival, but the quality of survival and tolerability of patients treated with SIRT was better than that of oral sorafenib.
Summary
Both SBRT and SIRT emphasize precise targeting and reduced damage to normal tissue in the treatment of liver cancer.
Of course, these two treatments are still complementary to liver cancer treatment, and as clinical data continue to be updated, knowledge of liver cancer treatment continues to improve, and science and technology continue to improve, radiotherapy, represented by SBRT or SIRT, will play an increasingly important role as a new hope and direction for the treatment of patients with advanced liver cancer.