Sydney School of Public Health, Sydney Medical School, Edward Ford Building (A27), The University of Sydney, NSW 2006, Australia.
U.O. Senologia Clinica e Screening Mammografico, Dipartimento di Radiodiagnostica, APSS Trento, Italy.
Breast. 2019 Feb;43:59-66. doi: 10.1016/j.breast.2018.11.001. Epub 2018 Nov 10.
Tomosynthesis is proposed to improve breast cancer assessment and staging. We compared tomosynthesis and mammography in estimating the size of newly-diagnosed breast cancers.
All pathologically-confirmed cancers detected in the STORM-2 trial (90 cancers, 85 women) were retrospectively measured on tomosynthesis by two independent readers. One reader also measured cancers on mammography. Relative mean differences (MDs) and 95% limits of agreement (LOA) with pathology were estimated for tomosynthesis and mammography within a single reader (Analysis 1) and between two readers (Analysis 2).
Where cancers were detected and hence measured by both tests, tomosynthesis overestimated pathologic size relative to mammography (Analysis 1: MD 5% versus 1%, Analysis 2: 7% versus 3%; P = 0.10 both analyses). There was similar, large measurement variability for both tests (LOA range: -60% to +166%). Overestimation by tomosynthesis was attributable to the subgroup with dense breasts (MDs = 12-13% versus 4% for mammography). There was low average bias for both tests in the low-density subgroup (MDs = 0-4%). LOA were larger in dense breasts for both tomosynthesis and mammography (P ≤ 0.02 all comparisons). Cancers detected only by tomosynthesis were more frequently in dense breasts (60-68%): for those tumours size was estimated with increased measurement variability (LOA ranging from -75% to +293%).
On average, tomosynthesis overestimates pathologic tumour size in women with dense breasts; that difference is more likely to impact management in women with larger tumours. The main advantage of tomosynthesis appears to be detecting mammographically-occult cancers; however tomosynthesis less accurately measured those cancers in dense breasts (large measurement variability).
断层合成被提议用于改善乳腺癌评估和分期。我们比较了断层合成和乳房 X 线摄影术在估计新诊断乳腺癌大小方面的作用。
回顾性地在 STORM-2 试验（90 例癌症，85 例女性）中由两位独立的读者在断层合成上测量所有经病理证实的癌症。一位读者还在乳房 X 线上测量了癌症。在单个读者（分析 1）和两位读者之间（分析 2），对断层合成和乳房 X 线摄影术的病理相对平均差值（MD）和 95%一致性界限（LOA）进行了估计。
在断层合成和乳房 X 线摄影术均能检测到并测量的癌症中，断层合成相对于乳房 X 线摄影术高估了病理大小（分析 1：MD 5%对 1%，分析 2：7%对 3%；两项分析均 P = 0.10）。两种检测方法的测量变异性都很大（LOA 范围：-60%至+166%）。断层合成的高估归因于致密乳腺亚组（MDs = 12-13%对乳房 X 线摄影术的 4%）。在低致密亚组中，两种检测方法的平均偏差均较小（MDs = 0-4%）。对于断层合成和乳房 X 线摄影术，致密乳腺的 LOA 均较大（所有比较均 P ≤ 0.02）。仅通过断层合成检测到的癌症更常见于致密乳腺（60-68%）：对于这些肿瘤，其大小的估计具有更大的测量变异性（LOA 范围从-75%到+293%）。
平均而言，在致密乳腺的女性中，断层合成高估了病理肿瘤大小；这种差异更有可能影响肿瘤较大的女性的治疗。断层合成的主要优势似乎在于检测乳房 X 线摄影术隐匿性癌症；然而，在致密乳腺中，断层合成对这些癌症的测量不够准确（测量变异性较大）。
