How do we know a treatment is working? Flashcards
What is cancer
Cancer is the uncontrolled growth of a cell.
What does the graph of cancer cell growth show?
It takes 10 years before a tumour reaches a certain number of cells where it produces symptoms and can be diagnosed.
What is the significance of early screening in cancer?
Early screening can expand the window of opportunity between diagnosis and death, increasing the chance for successful treatment.
What percentage of cancer patients are cured?
Around 50%.
What are the current cancer treatments available?
- Surgery: physically removing the tumour.
- Chemotherapy: using anti-cancer drugs to destroy the tumour.
- Radiation: using radiation to destroy cancer cells.
- Hormone therapy: turning off the hormones that are driving the cancers.
- Immunotherapy: harnessing the patient’s immune system to fight the cancer.
- Biological therapies: interfering with the biological pathways that are driving the cancer.
What are the objectives of cancer treatments?
- Cure the patient: kill or remove ALL cancer cells.
- Prolong patient survival: kill MOST cancer cells if the disease is too advanced.
- Palliate symptoms: kill SOME cancer cells when the cancer is very advanced.
What is remission?
Remission is when MOST cancer cells are killed, and there is no apparent cancer.
What is tumour progression?
Tumour progression occurs when treatment fails and the tumour continues to grow.
What is tumour efficacy?
Tumour efficacy refers to the response to treatment, such as tumour shrinkage.
How do we measure tumour response?
We use a method called RECIST, which involves measuring target lesions and assessing non-target lesions.
What survival times are used to assess treatment efficacy?
- Overall survival time: time from start of treatment to date of death.
- Disease-free survival time: time prior to tumour relapse after radical treatment.
- Progression-free survival time: survival time prior to tumour progression.
What is a clinical trial?
A clinical trial is any planned experiment involving patients designed to determine the most appropriate treatment method.
How do you assess the efficacy of new treatment?
By comparing with historical controls, concurrent controls, or through randomised concurrent control (RCT).
What is a single arm clinical trial?
A single arm clinical trial tests a new treatment on a group of patients without a comparison group.
What is the purpose of randomised controlled trials (RCT)?
RCTs aim to directly compare new treatments against standard treatments to provide unbiased evidence.
What are the phases of clinical trials?
Clinical trials start with Phase 1, then move to Phase 2, and finally Phase 3 trials.
How do we test if a treatment is working?
By estimating the treatment effect, confidence interval, and testing the hypothesis about the new treatment’s efficacy.
What are Kaplan-Meier survival curves?
Kaplan-Meier survival curves show the probability of survival over time from randomisation.
What are Kaplan-Meier survival curves?
These curves show the probability of survival (y axis) over time (x-axis) from randomisation.
What is the hazard ratio (HR) and how is it used to compare treatments in terms of survival time?
The HR for death with Nivolumab = 0.59, indicating a 41% reduction in risk of death with Nivolumab treatment. The 95% CI for this HR is 0.44 - 0.79, suggesting a minimum 21% reduction in risk even in the worst-case scenario. A p-value of 0.01 indicates highly statistically significant evidence that Nivolumab is superior to Docetaxel.
What is a waterfall plot?
Each bar shows an individual patient’s target lesion size change. Patients above the 0 line have increased lesion size, while those below have a reduction. The greater the size of the bar, the greater the shrinkage of the tumor. 58% of patients had a tumor response to this treatment with a 95% confidence interval (48% - 67%).
When may treatment be used without proof of a randomized controlled trial (RCT)?
Biologically based treatments targeted at a subgroup of patients, such as Ceritinib for ALK-driven tumors, can be used without RCT proof. The FDA approved this drug for ALK +ve lung cancer patients.
What is stratified medicine and how might it aid clinical trials?
Stratifying patients based on genetic molecular characteristics allows for targeted drug selection, improving outcomes. Predictive biomarkers can be collected to identify subgroups benefiting from treatment.
What is an example of a correlative biomarker study?
In a trial of cetuximab for advanced colorectal cancer, the HR was 0.77, indicating a 23% reduction in risk of death. The p-value was 0.005, showing significant evidence that cetuximab is better than best supportive care.
