Can CAR-T cure stage 4 cancer?

CAR-T therapy is one of the immunotherapeutic methods that have significantly changed approaches in modern oncology in recent years. The essence of the technology is that the patient’s own T cells are taken and then modified so that they produce chimeric receptors capable of recognizing specific antigens on the surface of tumor cells.

After modification, the cells are returned to the body. When they encounter the desired antigen, these T cells bind to it, trigger the destruction of the target cell, and effectively destroy it. This method has had a significant impact on the treatment outcomes for a number of hematological tumors, including certain forms of leukemia, lymphoma, and multiple myeloma.

The logic behind the therapy is generally transparent: if the patient’s own immune system is returned to a specific tumor marker, it is possible to achieve a more targeted effect than with conventional chemotherapy, which affects not only cancer but also healthy, rapidly dividing cells.

Successes in treating blood cancer and limitations in working with solid tumors

In oncohaematology, CAR-T demonstrates high remission rates, sometimes quite long-lasting.

In the case of solid tumors, the situation is much more complicated. Most stage 4 diagnoses relate to this type of neoplasm, and it is here that CAR-T faces a number of systemic problems.

Main barriers:

• There are no truly specific antigens. Solid tumors are heterogeneous: different cells within the same tumor may have different antigens. In addition, many potential targets are also present in normal tissues, which increases the risk of toxicity.
• Immunosuppressive environment. A solid tumor creates an environment that suppresses the activity of immune cells and hinders the work of CAR-T.
• Physical barriers. The dense structure of the tumor mass prevents the uniform penetration of cells.
• Toxicity. Targeted exposure to antigens present in healthy organs can cause severe side effects.

For this reason, the effectiveness of CAR-T, which has been proven in relation to blood cancer, has not yet been replicated in most solid tumors, including those diagnosed at later stages.

New developments and their significance for patients with stage 4 disease

Currently, CAR-T research is mainly focused on improving the cell constructs themselves and finding more effective ways to deliver them to the tumour. Several areas are being explored:

• CAR variants with a “logical activation” scheme, which are activated only in the presence of a specific set of antigens;
• strategies targeting multiple antigens simultaneously;
• modified CAR-T cells capable of secreting substances that enhance the immune response;
• Local administration of cells directly into the tumour area;
• Combining CAR-T with other types of immunotherapy or traditional treatments.

The aim of all these approaches is to improve targeting accuracy, cell stability in the body and their actual antitumour activity, especially in relation to solid tumours.

Initial results show a moderate but noticeable shift. In one 2025 study, patients with advanced gastric cancer and gastroesophageal junction tumours who received CAR-T therapy lived longer on average than the group receiving standard treatment. There is also data on glioblastoma: the use of dual-target CAR-T in relapses led to tumour reduction in some patients.

Taken together, these results indicate that the technology is gradually moving beyond blood diseases and beginning to show potential for certain types of solid tumours, including those in advanced stages.

Why it’s still wrong to say that stage 4 cancer can be cured?

It is currently incorrect to talk about a complete cure for most forms of stage 4 cancer using CAR-T. Although data is gradually being updated, this technology does not show consistent results across such a wide and diverse range of diseases.

The fourth stage combines a variety of oncological processes that differ significantly in terms of their mechanism of development, localisation, and rate of progression. Individual successful examples in one specific nosology cannot be transferred to other types of tumours, as CAR-T still demonstrates the best results primarily in blood diseases. Even with a good initial response, the long-term prognosis remains uncertain: tumours are capable of changing their antigenic profile, suppressing the immune response, or simply growing faster than the modified cells can act.

An additional problem is the risk of toxicity, as many potential targets on solid tumours are also found in normal tissues. The situation is complicated by restrictions on patient selection, the high cost of treatment, and differences in availability and regulatory requirements in different countries. Therefore, isolated cases of long-term remission cannot be taken as proof of a cure for all types of stage 4 cancer.

Outlook: progress, but many hurdles

Work on CAR-T continues. Target selection is getting better, combination treatments are under study, and delivery methods are being refined.

Based on recent results, it’s reasonable to expect that CAR-T and similar cell therapies will slowly expand into the treatment of solid tumors, including advanced ones.

But the current evidence does not support the idea that CAR-T can broadly “cure” stage 4 cancer. Too many biological, technical and logistical issues remain.

In real-life practice, CAR-T may give some patients more time or even a lasting remission — but this is not guaranteed and not universal. Outcomes depend on the tumor type, the antigen profile, the patient’s condition and access to treatment.

CAR-T is a major step forward for oncology. It has already transformed treatment for some blood cancers. Its role in late-stage solid tumors is growing, but consistent, wide-scale effectiveness is still a goal for the future, not the present.

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