When is Cancer Immunotherapy Most Effective?
“Cancer” is not a single disease but rather a category of diseases. Therefore, we usually see a great degree of variance when comparing the efficacy of different treatments.
In most general hospitals around the world, the first line of cancer treatment is usually a cancer-removal surgery (when possible), followed by chemotherapy. However, this “one size fits all” fails to acknowledge the differences between different cancer types, impacting a patient’s chance of survival.
In fact, some types of cancer cannot be cured with standard chemotherapy protocols. Patients diagnosed with these cancers are unlikely to gain many benefits from the treatment and should consider other alternatives instead – including immunotherapy.
What Types of Cancer Respond To Immunotherapy Best?
The principles of anti-cancer immunotherapy – that is, training the immune system to recognize mutated cancer cells as foreign, triggering an immune response to destroy them – apply to any type of malignant tumor.
So far, clinical trials have shown that some types of cancer are more sensitive to immunotherapy treatments than others. This may render a complete cure more likely, or radically increase the chances of radical remission.
Two types where immunotherapy yields the greatest benefit are:
Hematological malignancies
This cancer category originates from mutations in blood-forming tissue, such as the blood marrow. They are notoriously tricky to treat, as the body continuously produces new red and white blood cells. These cells will then circulate around the body rather than being confined to a specific organ or contained in a tumor, like a breast or lung cancer.
There are three main types of hematological malignancies: lymphoma, leukemia, and multiple myeloma. These diseases are among the ones that respond best to anti-cancer immunotherapy. Patients with these cancers are much more likely to enter a long-term, sustained remission.
Metastatic solid tumors
A solid tumor is an abnormal mass of tissue that doesn’t contain any liquid areas. If these tumors begin to grow uncontrollably, they are classified as malignant or cancerous.
Metastatic solid tumors usually begin in a single organ as a mutation of healthy organ tissue. As they grow, they can prevent the host organ from working properly. Eventually, a small part of the tumor (sometimes just a handful of cells) can break away from the original site and travel through the blood or lymph system into a different part of the body, which will give birth to new tumors. Once this happens, we say cancer has metastasized.
The results from anti-cancer immunotherapy vary greatly when it comes to metastatic solid tumors. As a general rule, complete remission rates for metastatic solid tumors are not as high as with hematological malignancies.
However, some types – most notable, metastatic malignant melanoma – do respond very nicely to immunotherapy. In these cases, patients can expect to significantly extend their life and improve their quality of life.
