Because the risk of cardio-toxic outcomes depends on type of drug, dose, cumulative dose, dose and schedule of administration, route, other drugs in regimen, inclusion of radiotherapy as well as patient demographics--pre-existing CV risk factors--it is often hard to tease out universal guidance. This context informs the debate around a recent article published in the New England Journal of Medicine. I think it is particularly relevant as the objective of the study is to potentially spare patients chemotherapy regimens with the use of a prediction tool, MammaPrint, a 70-gene signature test.
Comparatively data points in Quadrant IV suggests that Oncotype DX is less costly and more effective than MammaPrint. The graphic demonstrates the majority of data points are in Quadrant II, indicating that MammaPrint is the dominant strategy. The graphic isn't clearly depicted in the reference article for some reason but the trend is somewhat visible. When looking at efficacy and cost MammaPrint seems like a worthwhile clinical tool.
Confidence intervals gauge the utility of the data and accuracy of the estimates in the data. You may not be familiar with the one-sided bound described in the paper--lower one-sided bound but it means that 95% of the population is greater than 92% or the non-inferiority boundary.
The authors here did no such thing. Instead "The primary goal was to assess whether, among patients with high-risk clinical features and a low-risk gene-expression profile who did not receive chemotherapy, the lower boundary of the 95% confidence interval for the rate of 5-year survival without distant metastasis would be 92% (i.e., the noninferiority boundary) or higher."
The maximum level of where we reject the null hypothesis is alpha (significance level) and it is typically 0.05. The relevant data is somewhat hard to decipher. If you review the appendix you are reminded that red indicates chemotherapy and blue indicates no chemotherapy. You can also see p-values that should fail to reject the null hypothesis. I can only think that the expanded y axis leads to a bit of the distortion (inset). The disease-free survival (panel C and D) seem to show a benefit for patients on chemotherapy and in Table 2 you observe a P value of 0.03, HR 0.64 and 95% CI (0.43-0.95)
A total of 1550 patients (23.2%) were deemed to be at high clinical risk and low genomic risk. At 5 years, the rate of survival without distant metastasis in this group was 94.7% (95% confidence interval, 92.5 to 96.2) among those not receiving chemotherapy. The absolute difference in this survival rate between these patients and those who received chemotherapy was 1.5 percentage points, with the rate being lower without chemotherapy. Similar rates of survival without distant metastasis were reported in the subgroup of patients who had estrogen-receptor–positive, human epidermal growth factor receptor 2–negative, and either node-negative or node-positive disease.(also not significant)
The data suggest that it would be a roll of the dice--strictly due to chance. Are you feeling lucky?