Department of Radiation Oncology, Stanford University Medical Center, Stanford, CA, USA.
Int J Radiat Oncol Biol Phys. 2012 Aug 1;83(5):1521-7. doi: 10.1016/j.ijrobp.2011.10.022. Epub 2012 Jan 21.
We previously showed that metabolic tumor volume (MTV) on positron emission tomography-computed tomography (PET-CT) predicts for disease recurrence and death in head-and-neck cancer (HNC). We hypothesized that increases in MTV over time would correlate with tumor growth and biology, and would predict outcome. We sought to examine tumor growth over time in serial pretreatment PET-CT scans.
From 2006 to 2009, 51 patients had two PET-CT scans before receiving HNC treatment. MTV was defined as the tumor volume ≥ 50% of maximum SUV (SUV(max)). MTV was calculated for the primary tumor, nodal disease, and composite (primary tumor + nodes). MTV and SUV velocity were defined as the change in MTV or SUV(max) over time, respectively. Cox regression analyses were used to examine correlations between SUV, MTV velocity, and outcome (disease progression and overall survival).
The median follow-up time was 17.5 months. The median time between PET-CT scans was 3 weeks. Unexpectedly, 51% of cases demonstrated a decrease in SUV(max) (average, -0.1 cc/week) and MTV (average, -0.3 cc/week) over time. Despite the variability in MTV, primary tumor MTV velocity predicted disease progression (hazard ratio 2.94; p = 0.01) and overall survival (hazard ratio 1.85; p = 0.03).
Primary tumor MTV velocity appears to be a better prognostic indicator of disease progression and survival in comparison to nodal MTV velocity. However, substantial variability was found in PET-CT biomarkers between serial scans. Caution should be used when PET-CT biomarkers are integrated into clinical protocols for HNC.
我们之前的研究表明，正电子发射断层扫描-计算机断层扫描（PET-CT）上的代谢肿瘤体积（MTV）可预测头颈部癌症（HNC）的疾病复发和死亡。我们假设随着时间的推移，MTV 的增加将与肿瘤的生长和生物学相关，并可预测结果。我们试图在连续的预处理 PET-CT 扫描中检查肿瘤随时间的生长情况。
从 2006 年到 2009 年，51 例患者在接受 HNC 治疗前接受了两次 PET-CT 扫描。MTV 被定义为肿瘤体积≥最大标准摄取值（SUV(max))的 50%。原发性肿瘤、淋巴结疾病和复合病变（原发性肿瘤+淋巴结）的 MTV 均进行了计算。MTV 和 SUV 速度分别定义为 MTV 或 SUV(max)随时间的变化。Cox 回归分析用于检查 SUV、MTV 速度与结局（疾病进展和总生存）之间的相关性。
中位随访时间为 17.5 个月。两次 PET-CT 扫描之间的中位时间为 3 周。出乎意料的是，51%的病例在 SUV(max)（平均，-0.1 cc/周）和 MTV（平均，-0.3 cc/周）随时间推移而下降。尽管 MTV 存在变异性，但原发性肿瘤 MTV 速度可预测疾病进展（风险比 2.94；p = 0.01）和总生存（风险比 1.85；p = 0.03）。
与淋巴结 MTV 速度相比，原发性肿瘤 MTV 速度似乎是疾病进展和生存的更好预后指标。然而，在连续扫描之间，PET-CT 生物标志物存在很大的变异性。在将 PET-CT 生物标志物纳入 HNC 临床方案时应谨慎。
