USE of SUVmax tool in General Staging of NSCLC in FDG PET/CT
Although integrated computed/positron emission tomography (PET/CT) reveal lung cancer staging and imaging modality with the highest accuracy, the blatant diagnostic accuracy of the SUVmax for the lymph nodes still requires thorough scrutiny. Nevertheless, Zhao et al. (2021) note that SUV max is the vital parameter that accurately measures the tumor metabolic activities and provides essential prognostic data and information. Still, Yu et al. (2018) validate that PET/CT is noninvasive imaging that depends on functional molecular imaging that improves diagnostic accuracy and sensitivity. Besides, Yachi et al., (2019) findings reveal that PET/CT complements the traditional deficiencies imaging by promoting the mediastinal lymphadenopathy workup role. For example, the authors’ study showed that PET/CT specificity and sensitivity in diagnosing malignant and benign mediastinal lymph nodes were 89% and 87%, respectively. Therefore, the SUVmax tool in staging the NSCLC had the highest fidelity/accuracy in detecting the metastases lymph nodes compared with the CT scan.
Admittedly, the standard uptake value (SUV) staging tool is preferred over SUVmean in percentage variability in accuracy and specificity (Pareek et al., 2018). For example, SUVmean typically has a variability of 3% during observations, and such discrepancies decrease 3% when the SUVmax is incorporated. Besides, SUV max cut-off value (2.5%) helps differentiate between malignant and benign lesions. The authors reiterated that in their studies, the 2.5 SUVmax cut-off value appropriately maintains an excellent and reliable specificity while improving the sensitivity of the lymph nodes. In short, SUVmax reveals accurate information on its regional lymph nodes and its primary tumor’s metabolic activities.
SUVmax Inaccuracy in Terms of Specificity and Sensitivity in Staging
Although the SUVmax imaging specificity and sensitivity for NCSLC staging have improved with FDG-PET/CT introduction, the techniques have insufficient treatment protocol accuracy. Besides, the predictability and sensitivity value for malignancy reveals a value less than 80% in various studies (Pahk, 2019). Thus, a biopsy test helps validate the lymph node involvement except in malignancy probability cases of the mediastinum and peripheral lung cancer. In turn, the endobronchial ultrasonography (endoscopic technique) with aspirational needles (EBUSA-NA) helps in verifying the SUVmax FDG-PET results of findings (Yaprak, 2019). Similarly, using SUVmax of lymph nodes in metastasis prediction seems vital. Still, false positivity coaxes the authors to use higher SUVmax values rather than the traditional values such as 2.5 to elevate the metastasis accuracy.
According to Hua et al. (2021), the higher SUV max is considered vital in predicting the lymph node metastasis and invasion of lymphatic vessels only at an early stage. However, low sensitivity and specificity lead to false negativity and positivity in normal SUVmax due to inflammatory disease involvement with lymph nodes and microscopic metastasis that rise above the PET/CT spatial resolution (Nakanishi et al., 2021). The above causes result from immune reactions due to silicotic nodules, lung tumors, and anthracosis resulting from biomass exposure or intensive air pollution indoors. Therefore, Kaseda (2020) concludes that CT morphologic features and SUVmax combination improve diagnostic and prognosis accuracy and decrease the essential positive-false cases.
The Comparison of Tumor Ratio
Nobody denies that the primary treatment determinant provided to the patient with NSCLC is their mediastinal nodal status. Still, the sensitivity and efficacy of detecting lymph nodes depend on the type of ratio used. According to Lee et al. (2019) studies, with 530 patients undergoing NSCLC diagnosis, the SUV max to tumor size ratio was best in enhancing the survival of patients and solid in treatment response than SUV max alone. Similarly, the tumor size ratio confirmed a positive prognosis indication of NSCLC than primary tumor SUVmax during surgery and is vital in predicting the outcome and results for NSCLC advanced patients (Yu et al., 2018). Likewise, the SUV/max size ratio influenced by age only. Under survival examination, the SUV max tumor size ratio independently predicted the PPS, OS, and PFS than the SUV max alone.
On the other hand, Nakanishi et al. (2021) studies indicate that LR diagnosis on FDG-PET prior to surgery is a good LN metastasis predictor for victims with NSCLC cN2 than the TLG or SUVmax. However, TLG or SUVmax is the best predictor for adenocarcinoma patients with LN metastasis. Simultaneously, the Nakanishi et al. (2021) findings confirmed that LR was essential in LN metastasis diagnosis exclusionary than the SUVmax or TLG. For instance, the LN metastasis specificity and sensitivity were 66.7% and 84.1%, respectively, with LR and decreased the false-negatives results because of its significant-high sensitivity. Therefore, the findings reveal the positive-false adverse effects of LN benign in a small volume.
Conversely, Yachi et al. (2019) conducted a cohort study on 45 patients with SUV max (2.5-4.1) and 93 LN mediastinal. It was evident that the cut-off was 0.3 in predicting the malignancy value (specificity 71% and 91% sensitivity). The results verify that LR had higher sensitivity than SUV max, making it the best to predict the LN metastasis for NSCLC patients.
In the same line, 18-FDG PET has a vital influence on staging the NCLSC compared to conventional imaging methods NSCLC detection in various organs due to alteration in NSCLC binary stage in patients (Martucci et al., 2020). Therefore, the binary change automatically alters therapeutic management because LD-NSCLC benefits from radiation therapy’s curative intent. Similarly, binary change improves the 18-FDG PET/CT diagnostic fidelity. On the other hand, Xie et al. (2021) studies compared FDG-PET/CT with the measurable anatomical information (SAD) functional information (SUVmax) in predicting the LN status. When the authors reached the Int-score on the tumor SUVmax efficiency in the AUC and training cohort compared with 18-FDG PET/CT, it was evident that Int-score had higher diagnostic sensitivity and efficacy.
According to Hui et al. (2020) studies, the victims with SUVmax values greater than 2.5 correlated with TLG and MTV. The findings revealed that TLG and MTV were essential correlating with lymphocyte and WBC counts and tumor size. Likewise, The WBC count before treatment indicated systemic inflammation. At the same time, TLG and MTV volumetric parameters are associated with WBC hematological count. Still, Hua et al. (2020) verified that WBC count positively associates with F-DG PET/CT parameters, confirming that cytokines and upregulated aerobic glycolysis and tumor generated the highest quantity of lactic acid. Besides, the process initiated systemic inflammation through lactic acid-induced pathways. Therefore, the study revealed that the TNM stage had a high impact or influence for high SUVmax, PFS than SCC primary lesion components had poor NSCLC of OS prediction. Briefly, high 18-FDG PET/CT SUVmax values as prognostic factors related to low health and clinical responses in patients with neck and head cancer malignancies, cervical cancer, NSCLC, and renal carcinoma cells.
For instance, the mediastinal and SUV max are practical tools with the highest fidelity in predicting cancer prognosis. The effectiveness and accuracy are correlated with Liver SUVmax (LR) with biological factors affecting the progression and proliferation of cancer in NSCLC. Similarly, Farsad (2019) affirm that FDG PET/CT is more advantageous in delineating tumor affiliated with intensive atelectasis in detecting invaded areas not identified by the CT. Besides, PET escalates the diagnostic fidelity when examining the nodal status in detecting the metastatic disorder than the CT alone
Reiteratively, Zhao et al.’s (2021) findings reveal that LMR is the best simple marker of systematic inflammatory response in correlation with positive clinical outcomes. Again, LMR reflects the balance between monocytes’ effects of the unfavorable tumor promotion and the lymphatic system of anti-tumor immunity. Notably, LMR reflects the inflammatory host response, and SUVmax represents the primary tumor of the local metabolic status. In similar hematological and SUVmax parameter correlations in cancer, SUVmax correlated with NLR and LMR in predicting the OS and PFS and identifying the prognosis (Yaprak, 2019). In turn, the SUV-LR or SUVmax LMR scores tools are the best accurate cancer treatment prognosis and responses with significant and appropriate treatment strategies, particularly for advanced patients.
Kaseda (2020) used the SUV max of hilar LN and compared it with PET-CT to predict mediastinal. The results indicated that PET-CT was better than SUV max hilar LN in predicting mediastinal due to the highest sensitivity and specificity in prediction. Again, the PET-CT accuracy is more significant than hilar LNs than other findings (Yu et al., 2018). On the other hand, the PET-CT had higher false-positive results due to a higher inflammation rate than the hilar LN.
In summary, SUVmax tumor size is the best prognosis indicator in a patient with advanced NSCLC due to the highest sensitivity and specificity compared with size ratio, mediastinal ratio, liver ratio, and tumor ratio.
References
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