Analysis of Growth Curve Type in Pulmonary Nodules with Different Characteristics

: 背景与目的 计算机断层扫描（computed tomography, CT）随访评估肺内结节的生长特性是临床判断结节良恶性的常用策略。不同生物学行为的肺结节可能具有不同的生长速度和生长模式。本研究的目的是绘制不同类型肺结节的体积生长曲线，了解其生长方式，为判断结节性质并制定肺结节随访方案提供依据。方法 应用三维分析软件对111例接受2次及以上CT检查的肺结节（实性结节54例、亚实性结节57例）的影像资料进行回顾性分析。35例恶性及5例良性结节经病理或组织学确认，其余71例经两年随访无显著生长，经专家会诊确认为肺癌低危结节。所有结节按密度及性质分组：实性良性/低危结节、实性恶性结节、亚实性良性/低危结节、亚实性恶性结节。以随访间隔时间（d）为X轴，以随访结节的三维体积（mm3）和三维体积对数为Y轴，绘制体积线性及指数性生长曲线，由研究者主观观察曲线的形态。应用卡方检验比较不同性质肺结节的生长曲线的差异。结果 实性恶性结节中12例（66.7%）生长曲线快速上升，3例（16.7%）先平缓-后上升，2例（11.1%）缓慢上升，1例（5.56%）平直。亚实性恶性结节中8例（47.1%）呈快速上升型，4例（23.5%）缓慢上升，3例（17.6%）平直，2例（11.8%）为先下降-后上升型。实性良性/低危结节中5例（13.9%）呈下降型，17例（47.2%）平直，8例（21.6%）缓慢上升，6例（16.7%）呈波浪型。亚实性良性/低危结节中4例（10%）呈下降型，21例（52.5%）平直，9例（22.5%）缓慢上升，6例（15%）呈波浪型。良性/低危结节与恶性结节生长曲线分布存在显著性差异（χ2=42.4, P 1 cm), benign/low-risk subsolid nodules, and malignant subsolid nodules (diameter ≤1 cm and >1 cm). The follow-up interval time (d) were plotted on the x-axis, and the nodules' volume (mm3) and logarithmic volume were plotted on the y-axis. Two radiologists subjectively determined the type of growth curve. Chi-square test was performed to compare the growth curves of benign/low-risk and malignant nodules. RESULTS: Of 18 solid cancers, 12 cases (66%) were found with steep ascendant growth curves. Those of 3 cases (16.7%) were flat ascendant, 2 cases (11.1%) slowly ascendant, and 1 (5.56%) case flat. Of 17 subsolid cancers, 8 cases (47.1%) manifested steep ascendant growth curves. Those of 4 cases (23.5%) were slowly ascendant, 3 (17.6%) flat, and 2 (11.8%) descendant-ascendant. Of 36 benign/low-risk solid nodules, 5 cases (13.9%) manifested descendant growth curves, 17 cases (47.2%) flat, 8 cases (21.6%) slowly ascendant, and 6 cases (16.7%) undulate. Of 40 benign/low-risk subsolid nodules, 4 cases (10%) manifested descendant growth curves, 21 cases (52.5%) flat, 9 cases (22.5%) slowly ascendant, and 6 cases (15%) undulate. The distribution of growth curve types significantly differed between benign/low-risk and malignant nodules (χ2=42.4, P<0.01). CONCLUSIONS: The growth curves of lung cancers are heterogeneous. A steep ascendant curve is the main type for lung cancer, with the exception of flat, slowly ascendant, or even descendant curve. A slowly ascendant curve cannot exclude the diagnosis of lung cancer, especially for subsolid nodules.
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