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K. Kadota
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O17 - Anatomical Pathology I (ID 128)
- Event: WCLC 2013
- Type: Oral Abstract Session
- Track: Pathology
- Presentations: 1
- Moderators:K. Jones, K.F. To
- Coordinates: 10/29/2013, 10:30 - 12:00, Bayside 105, Level 1
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O17.05 - Accuracy and Interobserver Agreement in Identifying Histologic Subtypes in Stage I Lung Adenocarcinomas ≤3 cm Using Frozen Section (ID 2590)
11:15 - 11:25 | Author(s): K. Kadota
- Abstract
- Presentation
Background
The new IASLC/ATS/ERS classification of lung adenocarcinoma (ADC) histologic subtypes is now recommended for prognostic stratification. The ability to determine histologic subtype accurately by frozen section (FS) may help surgeons to choose limited resection versus anatomic resection in the management of lung ADC. The aim of this study is to investigate the accuracy and interobserver agreement of FS for predicting histologic subtype.Methods
FS and permanent section slides from 361 surgically resected stage I lung ADCs ≤3 cm were reviewed for predominant histologic subtype and presence or absence of lepidic, acinar, papillary, micropapillary, and solid patterns. To determine interobserver agreement, 50 cases were additionally reviewed by 3 pathologists. To test the accuracy of FS in determining degree of invasion in cases with predominantly lepidic growth pattern, 5 pathologists reviewed FS slides from 35 patients and attempted to discriminate between adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and lepidic predominant adenocarcinoma (LPA).Results
The accuracy of FS for predicting histologic subtype is shown in the Table. There was moderate agreement on the predominant histologic subtype between FS diagnosis and final diagnosis (κ=0.565). FS had high specificity for micropapillary and solid patterns (94% and 96%, respectively), but sensitivity was low (37% and 69%, respectively). The interobserver agreement was satisfactory (κ > 0.6, except for acinar pattern). All cases of AIS were correctly diagnosed using FS. For MIA, only 41.3% of FS diagnoses were correct, and 52% were overdiagnosed as LPA; for cases of LPA, 79% of FS diagnoses were correct.Parameter Accuracy, % (95% CI) Sensitivity, % (95% CI) Specificity, % (95% CI) κ Predominant histologic subtype Overall 68 (63–73) Not applicable Not applicable 0.565 Lepidic 90 (86–92) 75 (64–84) 93 (90–96) 0.681 Acinar 76 (71-80) 70 (61–77) 79 (73–84) 0.481 Papillary 85 (81-88) 62 (50–72) 91 (87–94) 0.527 Micropapillary 94 (91-96) 21 (9–40) 99 (97–100) 0.277 Solid 91 (88-94) 79 (67–87) 94 (90–96) 0.700 Presence or absence of each histologic pattern Lepidic 80 (76–84) 75 (69–80) 91 (84–96) 0.588 Acinar 89 (85–92) 90 (86–93) 67 (35–90) 0.252 Papillary 72 (67–77) 70 (64–75) 79 (69–87) 0.397 Micropapillary 67 (62–72) 37 (30–45) 94 (89–97) 0.321 Solid 84 (80–88) 69 (61–76) 96 (92–98) 0.670 Conclusion
FS can provide information on the presence of aggressive histologic patterns—micropapillary and solid—with high specificity but low sensitivity. FS is not suitable for determining the predominant pattern or degree of invasion. Although FS can be helpful in diagnosing AIS, it has poor accuracy in distinguishing MIA from LPA.Only Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.
