A common question among patients with lymphoma and multiple myeloma is: what is the success rate of CAR-T therapy? While publications often cite success rates between 70% and 90%, what does this actually mean? Given that CAR-T therapy is a relatively new treatment, offered by many medical centers for only the last 5-10 years, does it imply a cure for the disease or long-term remission? And if so, for how many years?
Below is a guide and glossary for the terms you may encounter.
The success rate of CAR T-cell therapy varies based on several factors, including the type of cancer being treated—there are many types of leukemia, lymphoma, and multiple myeloma—the stage of the disease, and individual patient factors such as age, physical condition, and prior treatments and medications. For some types of leukemia and lymphoma, response rates have been reported to be over 80%, and for multiple myeloma, around 90%.
What is the response rate of CAR-T therapy? Once you understand the terms below, you can explore the statistics of Sheba Hospital’s CAR-T treatment outcomes from 2015-2023.
Calculating the success rate of treatment for blood cancer diseases involves several key steps and considerations.
Here’s a detailed explanation:
- Defining Success
• Complete Remission (CR): No signs of cancer are detected after treatment.
• Partial Remission (PR): Cancer is significantly reduced but not completely gone.
• Overall Survival (OS): The percentage of patients still alive after a specific period, often 5 years.
• Progression-Free Survival (PFS): The time during and after treatment that the patient lives with the disease without it worsening.
• Disease-Free Survival (DFS): The time after treatment during which the patient shows no signs of cancer.
- Selecting the Patient Cohort
• Inclusion Criteria: Age, type and stage of blood cancer, previous treatments, and other medical conditions.
• Exclusion Criteria: Patients who do not meet the inclusion criteria.
- Data Collection
• Clinical Trials: Prospective studies where patients receive a specific treatment and are followed over time.
• Registry Data: Real-world data collected from medical records and cancer registries.
• Retrospective Studies: Analysis of past patient data to determine outcomes.
- Statistical Analysis
• Kaplan-Meier Survival Curves: Used to estimate the survival function and visualize the time until events like death or recurrence.
• Cox Proportional Hazards Model: Assesses the impact of various factors on survival rates.
• Response Rates: Calculated by dividing the number of patients who respond to treatment (CR or PR) by the total number of patients treated.
- Adjustments and Considerations
• Baseline Characteristics: Adjusting for factors like age, gender, and comorbidities that could affect outcomes.
• Follow-Up Duration: Ensuring a consistent follow-up period for all patients to compare outcomes fairly.
• Treatment Variability: Considering the type of treatment (chemotherapy, radiation, CAR-T therapy, etc.) and its variations.
- Reporting the Success Rate
• Overall Response Rate (ORR): Percentage of patients achieving CR or PR.
• Five-Year Survival Rate: Percentage of patients alive five years after diagnosis or treatment.
• Median Survival Time: The time at which 50% of the patients have survived.
Example Calculation
Let’s say a study follows 100 patients with a specific type of blood cancer over 5 years:
- Complete Remission (CR): 40 patients
- Partial Remission (PR): 30 patients
- No Response or Progression: 30 patients
Overall Response Rate (ORR) Calculation: ORR=(CR+PR)Total Patients×100\text{ORR} = \frac{(\text{CR} + \text{PR})}{\text{Total Patients}} \times 100ORR=Total Patients(CR+PR)×100 ORR=(40+30)100×100=70%\text{ORR} = \frac{(40 + 30)}{100} \times 100 = 70\%ORR=100(40+30)×100=70%
Five-Year Survival Rate Calculation: If 80 out of 100 patients are alive after 5 years: Five-Year Survival Rate=80100×100=80%\text{Five-Year Survival Rate} = \frac{80}{100} \times 100 = 80\%Five-Year Survival Rate=10080×100=80%
Factors Influencing Success Rate
- Type of Blood Cancer: Different types (e.g., leukemia, lymphoma, myeloma) have different prognosis and response rates.
- Stage at Diagnosis: Early-stage cancers generally have better outcomes.
- Patient Health: Overall health and comorbid conditions can affect survival and response rates.
- Treatment Advances: New therapies can significantly improve outcomes over time.
By considering these steps and factors, clinicians and researchers can accurately calculate and report the success rates of treatments for blood cancer diseases, helping to guide patient care and inform future research.
