EBM Flashcards
According to NHMRC - Level I evidence is?
A systematic review of level II studies.
According to NHMRC - Level II evidence is?
Depends on the aim. For intervention: Randomised controlled trial For prognosis and aetiology: a prospective cohort study
According to NHMRC - Level III-1 evidence is?
For an intervention, it is a pseudo randomised trial
According to NHMRC - Level III-2 evidence is?
A comparative study with concurrent controls: ▪ Non-randomised, experimental trial ▪ Cohort study ▪ Case-control study ▪ Interrupted time series with a control group
According to NHMRC - Level III-3 evidence is?
A comparative study WITHOUT concurrent controls: ▪ Historical control study ▪ Two or more single-arm study ▪ Interrupted time series without a parallel control group
According to NHMRC - Level IV evidence is?
Case series with either post-test or pre-test/post-test outcomes
Why have a 2:1 randomisation in a RCT? (4)
Easier to recruit - i.e. more likley to get study intervention More numbers in subgroup for later analysis More power when treatment responses are less precise The economical advantage when one arm is more expensive
Name 2 QOL assessment tools?
FACT - Functional Assessment of Cancer Therapy (with FACT-En (endometrial) FACT-O (Ovarian)) EORTC - QLQ (Quality of life questionnaires) general and specific cancer tools
Why are QOL important outcome measures? (3)
- They are important to patients
- Increased cancer survival creates larger groups of survivors with survivorship issues and plans
- where the treatment offers little benefit the impact of QoL may guide the usage of treatment
WHat is HRQOL / HRQL
The extent to which one’s usual or expected physical, emotional and social well-being are affected by a medical condition or its treatment
Subjective - appraisal on the impact of illness or its treatment. Pts with the same objective health status can report dissimilar HRQL
How does HRQL data inform treatments? (5)
- In clinical trials - compare treatments and HRQL as a method to determine overall benefit - esp when SE are considerable
- Planning for future care - ID requirement for care needs in the future
- Capturing changes in status during treatment.
- Predicting treatment response - in Lung Ca - change in HRQL predicted response to Rx
- Treatment decision-making - prolongation of life, without QOL is not a universally desired goal.
What is the Warburg effect?
Tumours tend to use glycolysis for energy even in aerobic conditions - “aerobic glycolysis”. ? dysfunctional mitochondria may be the cause of a higher rate of glycolysis.
What is the SUV
SUV is the standardised uptake value. It is a relative measure of FDG uptake in tissues. It is a ratio of the tracer in a region of interest in relation to the amount of FBG and the patients weight. If all the FDG was evenly distributed in the body the SUV would be 1. The SUV of a cervical lesion at Diagnosis was an independent RF for disease recurrence in a retrospective cohort of 287 women with stage IB –IVA Ca. Volume did not correlate with SUV. 3 prognostic groups were identified. SUV Max • = 5.2 = 95% 5yr OS • >5.2 - 13.3 = 70% 5yr OS • >13.3 = 44% 5 yr OS
What are the criteria for a screening test?
Modified Wilson screening criteria IATROGENIC
Important – the condition should be an important one
Acceptable - treatment for the disease
Treatment - and diagnostic facilities should be available
Recognisable - at an early stage of symptoms
Opinions - on who to treat as patients must be agreed
Guaranteed safety e.g. low radiation exposure
Examination - must be acceptable by the patient
Natural history - of the disease must be known
Inexpensive test
Continuous screening i.e. not a one-off
What is an odds ratio and how do you calculate one?
OR are used to compare the relative odds of the occurrence of the outcome of interest (e.g. disease or disorder), given exposure to the variable of interest (e.g. health characteristic, aspect of medical history).
The OR can also be used to determine whether a particular exposure is a risk factor for a particular outcome, and to compare the magnitude of various risk factors for that outcome.
OR=1 Exposure does not affect odds of the outcome
OR>1 Exposure associated with higher odds of the outcome
OR<1 Exposure associated with lower odds of the outcome
OR = (A/B) / (C/D) = AD / BC
What is a relative risk and how it is calculated. How does it differ from an OR?
The relative risk is the probability of an event in a treatment group (a / a+b) divided by the probability of an event in a non-treatment group (c / c + d)
The OR compares the odds of an event the treatment vs the odds in the control group. The i.e. (a /b) / (c/d)
Calculation of risk needs a people at risk denominator. in Case control or retrospective studies where the number of exposed people is not available the OR is calculate as the RR cannot be calculated. The RR can only be calculated when the people at risk denominator is known.
Multiple logistic regression, a frequently used multivariate technique, calculates adjusted ORs and not RRs.
Endometrial Ca - survival by grade and stage according to cancersurvival.com
