Why is it Difficult to Find New Cancer Treatments?

Cancer research focussing on finding new treatments is widely pursued. Although many new cancer treatments are successfully produced, most of those seem to extend the life of the patients for a few months, or years, and the process is many times perceived as extremely slow and expensive.

Photo by National Cancer Institute on Unsplash

Why is it so difficult to find cancer cures?

There are some reasons that apply to any research for new cancer treatments.

First, cancer treatment evaluation research involves accurate measurement of the response to therapy, which requires repeated evaluation through high-end imaging techniques including CT, MRI, PET-CT, etc., all of which are expensive and resource-consuming. Second, the operational expenses of the trial and all the safety precautions are also high. Third, is the development of treatment resistance among the cancer cells. Even if the resistance initially emerges in only few of the cancer cells, their turnover is so high that they quickly select themselves to outgrow non-resistant cancer cells. Fourth, the dysfunction of other body organs such as coexisting diabetes, heart disease, liver disease, kidney disease, etc. complicate the response to the therapy by interlinked and poorly understood mechanisms.

When it comes to challenges that are specific to individual therapies, there are unique problems in all therapies.

Surgical treatments attempt to remove all the cancer cells from the body if it has not spread extensively. Much of the cancer cases are diagnosed in later stages when the disease has spread extensively, and a surgical cure can only be obtained if the tumor is artificially shrunk using another therapy first. Finding new surgical treatments requires research on methods of the pre-surgical shrinking of cancer, and measurement of the extent of microscopic cancer spread (not visible while operating) into the lymphatics, surrounding tissues, and their timely removal. This requires excellent real-time pathology support.

Chemotherapy comprises of toxic chemicals that directly attack the cancer cells trying to kill them. Finding new chemotherapy agents involves research to find new molecular targets on cancer cells and then developing agents that can attack those targets without much collateral damage. These drug targets may be expressed in all or only a few of the patients, and finding them remains a big challenge. The situation becomes complex when these targets are also expressed on other body organs. Finding new chemotherapy targets often requires state of the art facilities for genomics and proteomics.

Radiation therapy also adopts more or less a similar approach of killing cancer cells but through radiation. Finding new radiation treatments requires research on methods to deliver targeted radiation via doses that are appropriate to kill cancer cells. This requires devices to support complex treatment planning and evaluation of radiation dosage and its effects on surrounding tissues requiring equipment that are capital extensive.

Immunotherapy stimulates the body's defense mechanisms and corrects imbalances of the immune system in order to kill cancer cells. Being the youngest out of all the therapies, this seems to have the highest untapped potential. However, the challenges that are seen in immunotherapy are unprecedented in terms of complexity. Advancing immunotherapy requires state of the art facilities for cellular research on live cancer cell lines and cell lines of B-cells and T-cells. In addition, the research requires delineating the complex interplay between proinflammatory and anti-inflammatory cytokines and its effect on cancer cells.

Finally, there are issues in collecting enough cases as each subtype of cancer remains a rare disease and it is difficult for a single center to collect enough patients. Therefore, more and more cancer research is carried out across multiple centers to pool the patients. However, this diversity brings its own challenges of genetic, racial, and other biological and social differences among the patients that seem to further complicate things.

References:

1. Current Challenges in Cancer Treatment

2. How Precision Oncology Helps Cancer Patients

3. Improving radiotherapy in cancer treatment: Promises and challenges

4. Grand Challenges in Surgical Oncology

5. Current Challenges in Cancer Immunotherapy

About the author: Dr. Naval Asija is a licensed MBBS Physician from India. MBBS is the equivalent of the MD degree offered by international medical schools. He is based in Delhi, India, and works as a medical writer, editor, and consultant. He supports medical researches as an author's editor, medical communication companies involved in medico-marketing activities, and medical technology companies in improving their products. He can be contacted via his LinkedIn Profile: https://www.linkedin.com/in/navalasija/