The overall survival of patients with operable pancreatic adenocarcinoma without distant metastases, according to their T stage at the time of surgery.

The Kaplan−Meier graph in Figure 1 describes the overall survival of patients with operable pancreatic adenocarcinoma without distant metastases, according to their T stage at the time of surgery. T1 indicates smaller primary tumour, while T2 and T3 indicate progressively increased primary tumour mass. The patients were followed up at regular intervals for approximately 65 months.

Figure 1 Overall survival of pancreatic patients, according to their T stage at the time of surgery.

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This graph shows the percentage of overall survival (from 0 to 100%; vertical y-axis) of cancer patients followed up for 65 months after surgical operation (from 0-65 months; horizontal x-axis). Patients are divided in three groups: T1 (blue line), T2 (green line) and T3 (red line). All lines fall progressively as months increase from left to right. The red line falls the most and is always below the other two. The blue line falls least and is always above the other two.

Overall survival of pancreatic patients, according to their T stage at the time of surgery.

A.Based on Figure 1, what is the percentage of patients with T1 and T3 tumours surviving at 24 months? What is the difference in the percentage of patients surviving between these two groups at 24 months? (Show your workings.)

(3 marks)

B.Apart from primary tumour size, which other two factors are considered in the staging of cancers? Why are these considered important?

(5 marks)

C.The data in this study uses ‘overall survival’ as an outcome. You have also learnt about ‘relapse-free survival’ and ‘progression-free survival’. Which of these two survival times could be measured in this cohort, and why?

(2 marks)