Impact of the pattern of lymph node metastasis on the clinical target volume in radiotherapy for thoracic esophageal squamous cell carcinoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the pattern of lymph node metastasis of thoracic esophageal squamous cell carcinoma (ESCC) after esophagectomy and its impact on the clinical target volume (CTV) delineation in radiotherapy fpr thoracic ESCC.</p><p><b>METHODS</b>The pattern of lymph node metastasis was retrospectively analyzed in 1077 patients with primary thoracic ESCC. All patients received esophagectomy with two- or three-field lymphadenectomy. The clinicopathologic factors related to lymph node metastasis were then analyzed using logistic regression analysis.</p><p><b>RESULTS</b>The rates of cervical, upper mediastinal, middle mediastinal, lower mediastinal and abdominal cavity lymph node metastasis were 16.7%, 33.3%, 11.1%, 5.6% and 5.6%, respectively. The rates of those node metastasis in the middle thoracic ESCC were 4.0%, 3.8%, 28.5%, 7.1% and 17.1%, respectively, and the rates of those node metastasis in the lower thoracic ESCC were 1.5%, 3.0%, 22.7%, 37.0% and 33.2%, respectively. The depth of tumor invasion, histologic differentiation and the length of tumor were showed to be statistically most significant risk factors of lymph node metastasis of ESCC (P < 0.001).</p><p><b>CONCLUSION</b>The depth of tumor invasion, histologic differentiation, and length of tumor were closely correlated with lymph node metastasis of ESCC. All these factors and tumor location should be considered comprehensively when designing the target volume for radiotherapy.</p>

Impact of PET/CT on precise radiotherapy planning for non-small cell lung cancer / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the impact of PET/CT on the clinical staging, target volume delineation and precise radiotherapy (PAR) planning for patients with non-small cell lung cancer (NSCLC).</p><p><b>METHODS</b>PET/CT scanning was performed in 58 histologically proven NSCLC patients for radical radiotherapy or surgery. The clinical staging of all patients was determined by PET/CT according to 1997 World Health Organization (WHO) staging system. The gross tumor volume (GTV) was delineated and three-dimensional conformal radiotherapy (3D-CRT) planning was established with identical parameters based on CT image and PET/CT fused image, respectively. The indexes including volume of GTV (V(GTV)), percentage of the total lung volume which received more than 20 Gy (V(20)), mean lung dose (MLD), tumor control probability (TCP), normal tissue complication probability (NTCP), and dose to spinal cord (Ds) were selected and evaluated. The quality of the two plans and the impact of PET/CT on PAR planning was compare and analyzed.</p><p><b>RESULTS</b>1. PET/CT image results changed the clinical stages in 21 of 58 (36.2%) patients with 14 upstaged and 7 downstaged, therefore, the management decisions were modified in 16 (27.6%) patients. 2. Among 32 patients who underwent surgery, PET/CT staging result was consistent with pathologic staging in 29 with one false negative and 2 false positive in lymph node staging. The sensitivity of PET/CT was 96.9% and accuracy 90.6%. 3. The differences of indexes including V(GTV) (P = 0.004), V(20) (P = 0.000) and MLD (P = 0.004) between the two radiotherapy plannings were statistically significant, whereas, the Ds, TCP and NTCP (left lung, right lung, skin and spinal cord) was not.</p><p><b>CONCLUSION</b>1. The impact PET/CT on clinical staging of NSCLC and PAR planning was remarkable. 2. PET/CT is more consistent with pathology in staging than CT and, therefore, is an important compensatory staging measure. 3. Compared with CT, PET/CT can reduce the V(GTV) in patients with atelectasis and obstructive pneumonitis when contouring the target volume, so can provide better protection for normal surrounding lung tissue. On the other hand, PET/CT is more sensitive in detecting mediastinal lymph node metastasis than CT, and the V(GTV) can be more precise and guaranteed. 4. Radiopneumonitis may be more effectively prevented because of significant decrease in V(20) and MLD by more precise planning based on PET/CT results. 5. PET/CT not only can provide satisfactory Ds, TCP and NTCP within clinical demand, but also more precise delineation of the radiation target volume and precise radiotherapy planning for NSCLC.</p>

Comparison of different threshold ~(18)FDG PET with computer tomography for defining gross tumor volume in non-small cell lung carcinoma / 中华放射肿瘤学杂志

Objective Under different standard uptake value(SUV),to assess gross tumor volume (GTV) definition for non-small cell lung cancer(NSCLC) with 18-fluoro-deoxy-glucose positron emission tomography (~(18)FDG PET) both under definite threshold (42 percent threshold) and various relative threshold (threshold SUV/maximum SUV) derived from the linear regressive function,threshold SUV=0.307?(mean target SUV)+0.588,with computer tomography (CT).Methods Of 20 patients with non-small cell lung cancer,the CT GTV (GTV_(?)).PET GTV with 42 percents threshold (GTV_(42%)) and PET GTV with relative threshold (GTV_(?)) were obtained and compared.Results The mean GTV_(42%),,mean GTV_(?) and mean GTV_(CT) was (13 812.5?13 841.4),(24 325.3?22 454.7) and (28 350.9?26 079.8)mm~3,respectively,with the difference in mean GTV among these three methods significant (F =10,P＜0.01).The GTV_(42%) was smaller than the GTV_(?) and the GTV_(CT)(P＜0.01),with i(?)significant difference between GTV_(?) and GTV_(CT)(P=0.125).Conclusion The relative threshold is more suitable to define the gross tumor volume than the definite threshold.