Clinical evaluation of atlas-based auto-segmentation in breast and nodal radiotherapy.

OBJECTIVES: Accurate contouring of anatomical structures allows for high-precision radiotherapy planning, targeting the dose at treatment volumes and avoiding organs at risk. Manual contouring is time-consuming with significant user variability, whereas auto-segmentation (AS) has proven efficiency benefits but requires editing before treatment planning. This study investigated whether atlas-based AS (ABAS) accuracy improves with template atlas group size and character-specific atlas and test case selection. METHODS AND MATERIALS: One clinician retrospectively contoured the breast, nodes, lung, heart, and brachial plexus on 100 CT scans, adhering to peer-reviewed guidelines. Atlases were clustered in group sizes, treatment positions, chest wall separations, and ASs created with Mirada software. The similarity of ASs compared to reference contours was described by the Jaccard similarity coefficient (JSC) and centroid distance variance (CDV). RESULTS: Across group sizes, for all structures combined, the mean JSC was 0.6 (SD 0.3, p = .999). Across atlas-specific groups, 0.6 (SD 0.3, p = 1.000). The correlation between JSC and structure volume was weak in both scenarios (adjusted R2-0.007 and 0.185).Mean CDV was similar across groups but varied up to 1.2 cm for specific structures. CONCLUSIONS: Character-specific atlas groups and test case selection did not improve accuracy outcomes. High-quality ASs were obtained from groups containing as few as ten atlases, subsequently simplifying the application of ABAS. CDV measures indicating auto-segmentation variations on the x, y, and z axes can be utilised to decide on the clinical relevance of variations and reduce AS editing. ADVANCES IN KNOWLEDGE: High-quality ABASs can be obtained from as few as ten template atlases.Atlas and test case selection do not improve AS accuracy.Unlike well-known quantitative similarity indices, volume displacement metrics provide information on the location of segmentation variations, helping assessment of the clinical relevance of variations and reducing clinician editing. Volume displacement metrics combined with the qualitative measure of clinician assessment could reduce user variability.

Patient attitudes towards undergoing additional breast biopsy for research.

BACKGROUND: Acquisition of additional breast tissue has become integral to breast oncology research. This questionnaire study examines patient willingness to undergo research-dedicated breast biopsies either at time of diagnostic biopsy (T1) or after carcinoma diagnosis has been confirmed and eligibility for a specific study established (T2), and influencing factors thereof. METHODS: Prior to consultation, patients attending breast clinics were recruited to complete a questionnaire examining willingness to undergo an extra fine needle aspirate (FNA) and/or core needle biopsy (CNB) for research either at T1 or T2. Descriptions of FNA and CNB procedures were supplied to those with no prior experience. Patient perspectives towards donating surplus tissue remaining from a diagnostic procedure and/or surgery for future research were also explored. FINDINGS: A total of 100 patients were recruited, 42% with prior history of breast carcinoma (BC), 22% with family history of BC (FHBC) and 65%/42% with previous experience of CNB/FNA respectively. Overall, 57% were willing to undergo additional biopsy at one or both time points. Willingness to undergo additional biopsy was greater for T1 than T2, but equivalent for CNB and FNA (willingness CNB T1, 50% vs T2, 26%, willingness FNA T1 50% vs T2 29%). A statistically significant increase in willingness to undergo CNB and/or FNA at T1 and/or T2 was seen in association with prior diagnosis of BC, FHBC, previous visit to breast clinic and prior experience of breast biopsy. 83% of patients expressed a willingness to allow surplus tissue to be stored in a biobank for future research. INTERPRETATION: Where possible patients should be approached to undergo baseline research biopsies at time of diagnostic process rather than subsequently. Patients do not find FNA more acceptable than core biopsy. Prior exposure to the biopsy procedure increases willingness to undergo research-dedicated biopsies.