RTOG 9804 Trial MCQ – Good-Risk DCIS Criteria
📘 Theme: Breast Surgery – DCIS (NEET SS / MCh / FMAS High Yield)
Clinical Breast Surgery MCQ
According to the RTOG 9804 trial, which of the following criteria defined a favourable (good-risk) ductal carcinoma in situ (DCIS)?
A. Less than 3.5 cm in size with a 2 mm free resection margin
B. Less than 2.5 cm in size with a 2 mm free resection margin
C. Less than 3 cm in size with a 3 mm free resection margin
D. Less than 2.5 cm in size with a 3 mm free resection margin
Answer: D. Less than 2.5 cm in size with a 3 mm free resection margin
Explanation
The RTOG 9804 trial evaluated radiotherapy in patients with good-risk DCIS treated with breast-conserving surgery. Eligible patients had low- or intermediate-grade DCIS measuring ≤2.5 cm with surgical margins of at least 3 mm. These criteria were used to define favourable DCIS.
Why other options are incorrect
- A: Tumour size criterion was not 3.5 cm.
- B: A 2 mm margin did not meet the RTOG 9804 eligibility requirement.
- C: The size cutoff was ≤2.5 cm, not 3 cm.
High-yield teaching points
- RTOG 9804 enrolled patients with "good-risk" DCIS.
- Eligibility required DCIS ≤2.5 cm and margins ≥3 mm.
- The study demonstrated a reduction in ipsilateral breast recurrence with radiotherapy.
- RTOG 9804 is frequently cited when discussing omission of radiotherapy in selected low-risk DCIS patients.