Many cancer medicines are built around chemotherapy. Chemotherapy causes individuals to experience both significant physical and mental stress and has given them great hope. Additionally, not all cancer cases respond to treatment as effectively as they should. Chemosensitivity testing seeks to identify these cancer cell resistances before therapy starts, helping avoid unsuccessful chemotherapies.

What are Chemotherapeutics and Chemotherapy?

Cells that divide uncontrollably and too quickly become cancerous. Chemotherapeutics, or medications that target and kill rapidly dividing cells, are a staple in cancer treatment. When planning chemotherapy, doctors today have access to many potent chemotherapeutics with various modes of action. It can be challenging to select from these the most effective drugs for treating a specific case of cancer. The patient's unique characteristics might affect the treatment's effectiveness. It could also be because of the type of tumour.

According to the origin tissue and stage of the malignancy, current cancer therapy guidelines aim to categorize cancer patients. They subsequently get cancer medication that will benefit each of these groups the most. Depending on the type of cancer, the patient gets chemotherapy in standardized combinations. This is done to maximize efficacy and reduce unfavourable drug effects.

Attributes of cancer treatment - chemosensitivity and chemoresistance

However, chemotherapy administered by the recommendations is not always equally successful. Unique conditions affect cancer. Additionally, even in tumours with a similar origin, a patient's cancer cells' chemosensitivity (susceptibility to a chemotherapeutic) may vary. Chemosensitivity, a characteristic of cancer cells, refers to the intensity of the tumour's response to a specific anticancer treatment. It details how a tumour responds to this chemical. It also includes how severely a medical professional stops its growth and whether the treatment causes the cells in the tumour to die. Chemosensitivity in cancer is hence a requirement for chemotherapy's effectiveness.

The opposite of chemosensitivity and chemoresistance. A chemo-resistant tumour can continue to develop even in the presence of a chemotherapeutic it is resistant to. This behaviour is very much like that of antibiotic-resistant bacteria. Therefore, utilizing this medication for chemotherapy would not be a wise choice. Fortunately, it is uncommon for malignancies to defy every possible form of treatment. Therefore, workable alternatives are easier to find if the chemoresistance shows up in advance. We want to assist you with this in some way.

Direct Chemosensitivity testing

Doctors use the same "chemosensitivity assay" techniques to evaluate both chemosensitivity and chemoresistance. They check if the patient's cancer cells may continue to divide and survive while undergoing chemotherapy treatment. There is a >95% chance that the source tumour is likewise resistant to the tested chemotherapeutic if cancer cells exhibit chemoresistance in a chemosensitivity experiment. Chemosensitivity assays excel at precisely predicting these resistances (or, more fitting: chemotherapy resistance assays). The likelihood of a favourable clinical response considerably increases by only providing chemotherapy agents that could inhibit the development of cancer cells in a chemosensitivity experiment.

In a chemosensitivity experiment, cancer cells that exhibit chemosensitivity imply that the source tumour is also susceptible to the chemotherapeutic under test. However, because no diagnostic test can yet fully imitate therapy resistance in the human body, medical professionals cannot predict the chemosensitivity of the source tumour from chemosensitivity assays with the same accuracy as chemoresistance.

Different chemosensitivity assays identify cancer cells that have survived. The Chemotherapy-Resistance-Test (CTR-Test) is our method of choice. It counts the quantity of freshly generated DNA to determine if there is a division in the cells from the tissue while chemotherapeutics treat them. This assay is highly selective to cancer cells since normal (non-cancerous) cells do not divide in them, rendering them invisible to the test. Other tests, which are more likely to be biased since non-cancerous cells are still alive, measure the amount of ATP (an unstable chemical utilized to transport energy in living cells).

Indirect Chemosensitivity testing

All chemosensitivity assays described above require living cancer cells. Yet, stored and dead tumour samples can if acquired recently still hold information about the chemosensitivity of the tumour they originated from. In this case, professionals can extrapolate chemosensitivity from analyzing biomarkers; characteristic biological features of the tumour that the doctors can associate with therapy outcome. By assessing relevant biomarkers for multiple therapies, a medical professional can generate an individual profile of the tumour for predicting therapy efficacy.

Chemosensitivity Assays in Targeted Cancer Therapies

Doctors increasingly use chemotherapies for cancer in conjunction with or substitute for so-called targeted cancer therapies. Drugs used in targeted therapy precisely target one of the genetic changes (mutations); that cause uncontrolled cell proliferation and cancer development in previously healthy tissues. As a result, targeted medications are better than chemotherapeutic drugs at telling cancer cells apart from healthy cells. They have fewer side effects, are better targeted at cancer cells, and can be pretty powerful in the fight against the disease. But only if the cancer being treated has the precise mutations the medicine is meant to treat.

As a result, the existence of a select few particular mutations significantly impacts the (chemo)sensitivity of cancer cells to targeted therapy. Consequently, it's crucial to customize the therapy to the patient. Doctors can use the abovementioned techniques for chemosensitivity testing to determine the likelihood of response in targeted cancer therapy.

Conclusion

Indirect efficacy assessment has already been done for several recently targeted therapy medications by analysis of selected molecular-based biomarkers because therapeutic effectiveness is heavily dependent on a few unique mutations. Direct efficacy tests for specific medications are also being developed or are already available.