Johnson C R, Thames H D, Huang D T, Schmidt-Ullrich R K
Department of Radiation Oncology, Medical College of Virginia, Richmond 23298-0058, USA.
Int J Radiat Oncol Biol Phys. 1995 Sep 30;33(2):281-7. doi: 10.1016/0360-3016(95)00119-j.
While tumor volume is an important parameter predicting clinical outcome, its relationship to clonogen number remains uncertain. This uncertainty is related to many factors, among them treatment response heterogeneity, which obscures the influence of patients and treatment-related parameters. In this study, we analyze the effect of tumor volume on local and regional recurrence in a setting tightly controlled for dose, treatment time, and patient selection. The hypothesis that changes in clonogen number scale directly with changes in tumor volume is tested.
Using digital reconstruction of diagnostic computed tomography (CT) scans, primary and total tumor volumes were estimated in 51 cases of advanced squamous cell carcinoma of the head and neck. All patients were managed with a concomitant boost accelerated superfractionated schedule to a median dose of 70.2 Gy. Clinical data were fitted to a mixture model to relate tumor volume parameters to control probability where volume and clonogen number were related by the relationship m = a.Vb, where m is initial clonogen number, a is a proportionality constant, V is tumor volume, and b is the volume exponent.
Tumor volume estimates for primary tumor ranged from 3-196 cm3 and for total tumor volume 5-196 cm3. Actuarial local-regional control is 63%. The estimated volume exponent b is 0.85 (95%, confidence interval (c.i.): 0.40-1.29) for primary tumor volume and 1.1 (95%, c.i.: 0.33-1.85) for total tumor volume.
This study quantifies the adverse influence of tumor volume on local-regional disease control in advanced head and neck cancer. The derived volume exponent approximates to one, the theoretical expectation if the growth fraction is roughly constant and clonogen number increases linearly with volume. Finally, these results suggest that radiobiological parameters are more reliably estimated from clinical data with narrowly defined strata.
虽然肿瘤体积是预测临床结果的一个重要参数，但其与克隆源细胞数量的关系仍不明确。这种不确定性与许多因素有关，其中包括治疗反应的异质性，这掩盖了患者和治疗相关参数的影响。在本研究中，我们在严格控制剂量、治疗时间和患者选择的情况下，分析肿瘤体积对局部和区域复发的影响。对克隆源细胞数量的变化与肿瘤体积的变化直接成比例的假设进行了检验。
利用诊断性计算机断层扫描（CT）扫描的数字重建，对51例晚期头颈部鳞状细胞癌患者的原发肿瘤体积和总肿瘤体积进行了估计。所有患者均采用同步加量加速超分割方案，中位剂量为70.2 Gy。将临床数据拟合到一个混合模型中，以将肿瘤体积参数与控制概率相关联，其中体积和克隆源细胞数量通过关系m = a.Vb相关联，其中m是初始克隆源细胞数量，a是比例常数，V是肿瘤体积，b是体积指数。
原发肿瘤的肿瘤体积估计范围为3 - 196 cm³，总肿瘤体积为5 - 196 cm³。精算局部区域控制率为63%。原发肿瘤体积的估计体积指数b为0.85（95%，置信区间（c.i.）：0.40 - 1.29），总肿瘤体积为1.1（95%，c.i.：0.33 - 1.85）。
本研究量化了肿瘤体积对晚期头颈癌局部区域疾病控制的不利影响。导出的体积指数接近1，这是生长分数大致恒定且克隆源细胞数量随体积线性增加时的理论预期。最后，这些结果表明，从定义狭窄分层的临床数据中能更可靠地估计放射生物学参数。
