| ObjectiveTo discuss the value of PET-CT in detecting different historical types of NSCLC and its lymph node metastasis.MethodsA retrospective, single-institution review of225patients pathologically proven SCC or AC and had PET/CT scanning at first affiliated hospital, college of medicine, Zhejiang University.114of them were males while84were females. The mean age was61.6years. Compare SUVmax and diameter of primary tumor and metastatic lymph nodes between SCC and AC. In surgery patients, compare SUVmax and diameter of primary tumor in SCC and AC respectively. Lymph node staging was pathologically confirmed on tissue specimens obtained at thoracotomy. At last, analyze the correlation between lymph node SUVmax and its diameter in SCC and AC respectively and the correlation between lymph node SUVmax and primary tumor SUVmax respectively. ResultsThere were225patients in our study, including66SCC and159AC. The SUVmax of primary tumor of SCC was11.0±4.1compared with7.4±5.0for AC (P<0.001). The diameter of primary tumor of SCC was39.5±17.0millimeter compared with25.5±8.9millimeter for AC (P<0.001). A total of122patients were treated with surgery and517nodal stations were evaluated, including195for SCC and322for AC. The SUVmax of metastatic lymph nodes in SCC group was4.6±3.1compared with3.6±2.5for AC group (P=0.221). And the diameter of metastatic lymph nodes in SCC was12.0±5.7millimeter compared with12.7±5.5millimeter for AC (P=0.635). In the patients treated with surgery, tumor SUVmax of patients with lymph node metastasis was9.3±4.6, greater than that of patients without lymph node metastasis,5.5±3.9in AC group (P<0.001). The difference was not significant in SCC group (P=0.182). Tumor diameter between patients with and without lymph node metastasis was no significant difference both in SCC (P=0.239) and AC group (P=0.308). Lymph nodes were deemed malignant when their SUVmax was higher than background (criterion1), PET-CT had a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of48.1,88.1,52.0,91.8and86.7%in SCC group and57.5,95.9,82.1,87.2and86.3%in AC group respectively for lymph node evaluation. Lymph nodes were deemed malignant when SUVmax was above2.5(criterion2), PET-CT had a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of37.0,90.5,38.5,89.9and83.1%in SCC group and40.0,96.3,78.0,82.9and82.3%in AC group respectively for lymph node evaluation. Sensitivity of PET-CT for lymph node detecting with criterion1is higher than criterion2both in SCC (P=0.042) and AC group (P=0.027), while specificity was not significantly different between criteria1and criteria2in both SCC and AC group. There was no correlation between the tumor SUVmax and metastatic lymph nodes’SUVmax both in SCC (P=0.657) and AC group (P=0.119), while SUVmax of metastatic lymph nodes were positively correlated with the size of metastatic lymph nodes both in SCC group (P=0.006, R=0.673) and AC group (P=0.001, R=0.6).ConclusionsPET-CT has value in differentiate SCC and AC clinically. It is better to evaluate lymph node metastasis combining its SUVmax and diameter. It is also better regarding background as reference when evaluate lymph node metastasis with PET-CT. The sensitivity of PET/CT in detecting nodal metastasis is too low to avoid any further invasive staging procedure both in patients with SCC and AC. |
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