[18F]fluoro-2-deoxyglucose-positron emission tomography for the assessment of histopathological response after preoperative chemoradiotherapy in advanced oral squamous cell carcinoma

Volume-based 18F-fluorodeoxyglucose positron emission tomography/computed tomography parameters correlate with delayed neck metastasis in clinical early-stage oral squamous cell carcinoma

OBJECTIVE

There is no known preoperative marker that can effectively predict the risk of delayed neck metastasis (DNM), which is an important factor that determines the prognosis of early-stage oral cancer. In this study, we examined whether 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET)/computed tomography (CT) uptake parameters of primary cancer can predict the risk of DNM in early-stage oral squamous cell carcinoma (OSCC).

METHODS

Data from patients with stage I-II OSCC who underwent surgical resection of the primary tumor without elective neck dissection between January 2009 and December 2016 were retrospectively reviewed. Patient characteristics, histopathological factors, and PET/CT parameters (maximum standardized uptake value [SUVmax], metabolic tumor volume [MTV], and total lesion glycolysis [TLG]) were evaluated for their association with DNM. DNM rates were calculated, and the parameters that were statistically significant in the univariate analysis were used as explanatory variables. Independent factors associated with DNM were identified using multivariate analysis. For all statistical analyses, p-values < 0.05 were considered statistically significant.

RESULTS

Data from 71 patients were analyzed in the study. The overall DNM rate among all patients was 21.8%. The univariate analysis showed that the T classification, depth of invasion, pattern of invasion, lymphovascular invasion, SUVmax, MTV, and TLG were significant predictors of DNM. However, the multivariate analysis revealed that only the depth of invasion, MTV, and TLG were independent predictors of DNM.

CONCLUSION

This study suggests that, in addition to conventional predictors, volume-based PET parameters are useful predictors of DNM in those with early-stage OSCC.

18F-FDG PET cannot predict expression of clinically relevant histopathological biomarkers in head and neck squamous cell carcinoma: a meta-analysis

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is a common cancer. Positron emission tomography (PET) with 18F-fluorodeoxyglucose (18F-FDG) is a widely used imaging modality in HNSCC.

PURPOSE

To provide evident data about associations between 18F-FDG PET and histopathology in HNSCC.

MATERIAL AND METHODS

The MEDLINE database was screened for associations between maximum standard uptake values (SUV_max) derived from 18F-FDG PET and histopathological features in HNSCC up to May 2020. Only papers containing correlation coefficients between SUV_max and histopathology were acquired. Overall, 23 publications were collected.

RESULTS

The following correlations were calculated: KI 67: 12 studies (345 patients), pooled correlation coefficient (PCC): 0.23 (95% confidence interval [CI] 0.06-0.40); hypoxia-inducible factor-1α: eight studies (240 patients), PCC: 0.24 (95% CI 0.06-0.42); microvessel density: three studies (64 patients), PCC: 0.33 (95% CI 0.02-0.65); vascular endothelial growth factor: two studies (59 cases), PCC: 0.27 (95% CI 0.02-0.51); tumor suppressor protein p53: four studies (159 patients), PCC: 0.05 (95% CI -0.41 to 0.51); epidermal growth factor receptor: two studies (124 patients), PCC: 0.21 (95% CI 0.05-0.37); tumor cell count: three studies (67 patients), PCC: 0.18 (95% CI -0.06 to 0.42); tumor cell apoptosis: two studies (40 patients), PCC: 0.07 (95% CI = -0.85 to 0.99); B-cell lymphoma-2 protein: two studies (118 patients); PCC: 0.04 (95% CI -0.65 to 0.74); glucose-transporter 1: 10 studies (317 patients), PCC: 0.20 (95% CI 0.10-0.30).

CONCLUSION

SUV_max derived from 18F-FDG PET cannot reflect relevant histopathological features in HNSCC.

FDG PET correlates weakly with HIF-1 expression in solid tumors: a meta-analysis

BACKGROUND

Hypoxia-inducible factor (HIF)-1α plays a key role in hypoxic adaptation of tumor cells. Overexpression of HIF-1α is associated with tumor aggressiveness and worse prognosis in several malignancies. Presumably, expression of HIF-1a may be reflected by positron emission tomography with 2-deoxy-2 [fluorine-18] fluoro-D-glucose (18F-FDG PET). There are inconsistent data about relationships between FDG PET and HIF-1α.

PURPOSE

To provide evident data about associations between maximum standardized uptake value (SUV_max) and HIF-1α expression in solid tumors.

MATERIAL AND METHODS

MEDLINE, SCOPUS, and EMBASE databases were screened for relationships between SUV and HIF-1α up to August 2019. Overall, 21 studies with 1154 patients were identified. The following data were extracted from the literature: authors; year of publication; number of patients; and correlation coefficients.

RESULTS

Correlation coefficients between SUV_max and HIF-1α were in the range of -0.51-0.71. The pooled correlation coefficient was 0.27 (95% confidence interval [CI] = 0.14-0.41). Furthermore, correlation coefficients for some tumor entities were calculated. For this sub-analysis, data for primary tumors with >2 reports were included. The calculated correlation coefficients in the analyzed subgroups were as follows: head and neck squamous cell carcinoma: ρ = 0.25 (95% CI = 0.07-0.42); non-small lung cell cancer: ρ = 0.27 (95% CI = -0.14-0.67); uterine cervical cancer: ρ = -0.09 (95% CI = -0.89-0.71); thymic tumors: ρ = 0.39 (95% CI = 0.04-0.58).

CONCLUSION

SUV_max of FDG PET correlated weakly with expression of HIF-1α both in overall sample and tumor subgroups. Therefore, FDG PET cannot be used for prediction of hypoxia in clinical practice.

PET/CT-Based Response Evaluation in Cancer-a Systematic Review of Design Issues

Positron emission tomography/x-ray computed tomography (PET/CT) has long been discussed as a promising modality for response evaluation in cancer. When designing respective clinical trials, several design issues have to be addressed, especially the number/timing of PET/CT scans, the approach for quantifying metabolic activity, and the final translation of measurements into a rule. It is unclear how well these issues have been tackled in quest of an optimised use of PET/CT in response evaluation. Medline via Ovid and Science Citation Index via Web of Science were systematically searched for articles from 2015 on cancer patients scanned with PET/CT before and during/after treatment. Reports were categorised as being either developmental or evaluative, i.e. focusing on either the establishment or the evaluation of a rule discriminating responders from non-responders. Of 124 included papers, 112 (90 %) were accuracy and/or prognostic studies; the remainder were response-curve studies. No randomised controlled trials were found. Most studies were prospective (62 %) and from single centres (85 %); median number of patients was 38.5 (range 5-354). Most (69 %) of the studies employed only one post-baseline scan. Quantification was mainly based on SUVmax (91 %), while change over time was most frequently used to combine measurements into a rule (79 %). Half of the reports were categorised as developmental, the other half evaluative. Most development studies assessed only one element (35/62, 56 %), most frequently the choice of cut-off points (25/62, 40 %). In summary, the majority of studies did not address the essential open issues in establishing PET/CT for response evaluation. Reasonably sized multicentre studies are needed to systematically compare the many different options when using PET/CT for response evaluation.

A combined analysis of maximum standardized uptake value on FDG-PET, genetic markers, and clinicopathological risk factors in the prognostic stratification of patients with resected oral cavity squamous cell carcinoma

OBJECTIVE

Clinical outcomes of patients with resected oral cavity squamous cell carcinoma (OCSCC) chiefly depend on the presence of specific clinicopathological risk factors (RFs). Here, we performed a combined analysis of FDG-PET, genetic markers, and clinicopathological RFs in an effort to improve prognostic stratification.

METHODS

We retrospectively reviewed the clinical records of 2036 consecutive patients with first primary OCSCC who underwent surgery between 1996 and 2016. Of them, 345 underwent ultra-deep targeted sequencing (UDTS, between 1996 and 2011) and 168 whole exome sequencing (WES, between 2007 and 2016). Preoperative FDG-PET imaging was performed in 1135 patients from 2001 to 2016. Complete data on FDG-PET, genetic markers, and clinicopathological RFs were available for 327 patients.

RESULTS

Using log-ranked tests based on 5-year disease-free survival (DFS), the optimal cutoff points for maximum standardized uptake values (SUV-max) of the primary tumor and neck metastatic nodes were 22.8 and 9.7, respectively. The 5-year DFS rates were as follows: SUVtumor-max ≥ 22.8 or SUVnodal-max ≥ 9.7 (n = 77) versus SUVtumor-max < 22.8 and SUVnodal-max < 9.7 (n = 250), 32%/62%, P < 0.001; positive UDTS or WES gene panel (n = 64) versus negative (n = 263), 25%/62%, P < 0.001; pN3b (n = 165) versus pN1-2 (n = 162), 42%/68%, P < 0.001. On multivariate analyses, SUVtumor-max ≥ 22.8 or SUVnodal-max ≥ 9.7, a positive UDTS/WES gene panel, and pN3b disease were identified as independent prognosticators for 5-year outcomes. Based on these variables, we devised a scoring system that identified four distinct prognostic groups. The 5-year rates for patients with a score from 0 to 3 were as follows: loco-regional control, 80%/67%/47%/24% (P < 0.001); distant metastases, 13%/23%/55%/92% (P < 0.001); DFS, 74%/58%/28%/7% (P < 0.001); and disease-specific survival, 80%/64%/35%/7% (P < 0.001) respectively.

CONCLUSIONS

The combined assessment of tumor and nodal SUV-max, genetic markers, and pathological node status may refine the prognostic stratification of OCSCC patients.

Downregulation of DHRS9 is associated with poor prognosis in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) has a high potential for local invasion and nodal metastasis. Therefore, early detection and elucidation of the detailed molecular mechanisms underlying OSCC are essential. Dehydrogenase/reductase member 9 (DHRS9) is downregulated in recurrent OSCC. Although DHRS9 is reported to act as a tumour suppressor in several malignancies, its expression in OSCC cells is unknown. In this study, we examined DHRS9 expression immunohistochemically in specimens from a sample of 98 OSCC patients. Reduced DHRS9 expression was observed in 68 of 98 patients (69.4%) with OSCC. A significant association was found between low DHRS9 expression and local progression (T factor) (p = 0.0135). Furthermore, patients with low DHRS9 expression had a significantly poorer prognosis than those with high DHRS9 expression (p = 0.0443). In multivariate analysis using the Cox proportional hazards model, decreased DHRS9 expression strongly correlated with worse prognosis. The study findings suggest that DHRS9 might be a useful diagnostic and prognostic marker for OSCC.

Hallmarks of Cancer-Related Newly Prognostic Factors of Oral Squamous Cell Carcinoma

Head and neck cancer, including oral squamous cell carcinoma (OSCC), is the sixth leading malignancy worldwide. OSCC is an aggressive tumor and its prognosis has exhibited little improvement in the last three decades. Comprehensive elucidation of OSCC's molecular mechanism is imperative for early detection and treatment, improving patient survival. Based on broadly accepted notions, OSCC arises from multiple genetic alterations caused by chronic exposure to carcinogens. In 2011, research revealed 10 key alterations fundamental to cancer cell development: sustaining proliferative signaling, evading growth suppressors, avoiding immune destruction, activating invasion and metastasis, tumor-promoting inflammation, enabling replicative immortality, inducing angiogenesis, genome instability and mutation, resisting cell death, and deregulating energetics. This review describes molecular pathological findings on conventional and novel hallmarks of OSCC prognostic factors. In addition, the review summarizes the functions and roles of several molecules as novel OSCC prognosticators.

Role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in predicting pathological response to preoperative super-selective intra-arterial chemoradiotherapy for advanced squamous cell carcinoma of the mandible

Introduction

Although chemoradiotherapy (CRT) for oral squamous cell carcinoma (SCC) has been shown to preserve organ function and improve cosmetic results, site-specific data, especially mandible, are limited. The aim of this study was to evaluate the predictability of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) on response to super-selective intra-arterial CRT for advanced SCC of the mandible.

Methods

Fifteen patients with advanced SCC of the mandible underwent super-selective intra-arterial CRT followed by radical resection. Maximum standardized uptake value (SUVmax) of the mandibular lesion was evaluated with FDG-PET/CT before and after CRT. The SUVmax before and after CRT was defined as pre-SUVmax and post-SUVmax, respectively. The difference between pre- and post-SUVmax was calculated as SUVmax reduction rate to evaluate treatment response of the mandibular lesion. Each SUVmax reduction rate and surgical specimen of the corresponding lesion was analyzed to evaluate an accuracy of the modality for predicting pathological response.

Results

The median of pre-SUVmax was significantly lower than that of post-SUVmax (p = 0.001). Of the 15 patients, 6 had a pathological complete response (pCR) and 9 had a non-pCR. Neither pCR patients nor non-pCR patients showed significant difference of the median of SUVmax between pre- and post-CRT (pre-CRT p = 0.099 post-CRT p =0.074). The SUVmax reduction rate in patients with pCR was significantly higher than that with non-pCR (p = 0.002). Receiver operating characteristic analysis revealed that the optimal cut-off point of the reduction rate was 64.7%, with 83% sensitivity and 100% specificity.

Conclusions

These results concluded that SUVmax reduction rate can predict pathological complete response of preoperative super-selective intra-arterial CRT for advanced SCC of the mandible.

Correlation between the Uptake of 18F-Fluorodeoxyglucose (18F-FDG) and the Expression of Proliferation-Associated Antigen Ki-67 in Cancer Patients: A Meta-Analysis

Objective

To study the correlation between ¹⁸F-FDG uptake and cell proliferation in cancer patients by meta-analysis of published articles.

Methods

We searched PubMed (MEDLINE included), EMBASE, and Cochrane Database of Systematic Review, and selected research articles on the relationship between ¹⁸F-FDG uptake and Ki-67 expression (published between August 1, 1994-August 1, 2014), according to the literature inclusion and exclusion criteria. The publishing language was limited to English. The quality of included articles was evaluated according to the Quality Assessment of Diagnosis Accuracy Studies-2 (QUADAS-2). The correlation coefficient (r) was extracted from the included articles and processed by Fisher's r-to-z transformation. The combined correlation coefficient (r) and the 95% confidence interval (CI) were calculated with STATA 11.0 software under a random-effects model. Begg's test was used to analyze the existence of publication bias and draw funnel plot, and the sources of heterogeneity were explored by sensitivity and subgroup analyses.

Results

According to the inclusion and exclusion criteria, 79 articles were finally included, including 81 studies involving a total of 3242 patients. All the studies had a combined r of 0.44 (95% CI, 0.41-0.46), but with a significant heterogeneity (I² = 80.9%, P<0.01). Subgroup analysis for different tumor types indicated that most subgroups showed a reduced heterogeneity. Malignant melanoma (n = 1) had the minimum correlation coefficient (-0.22) between ¹⁸F-FDG uptake and Ki-67 expression, while the thymic epithelial tumors (TETs; n = 2) showed the maximum correlation coefficient of 0.81. The analytical results confirmed that correlation between ¹⁸F-FDG uptake and Ki-67 expression was extremely significant in TETs, significant in gastrointestinal stromal tumors (GISTs), moderate in patients with lung, breast, bone and soft tissue, pancreatic, oral, thoracic, and uterine and ovarian cancers, average in brain, esophageal and colorectal cancers, and poor in head and neck, thyroid, gastric and malignant melanoma tumors. Subgroup analysis indicated that positron emission tomography (PET) or PET/CT imaging technology or Ki-67 and standardized uptake value (SUV) measurement technology did not significantly affect the results of r values, and Begg's test showed no significant publication bias.

Conclusion

In cancer patients, ¹⁸F-FDG uptake showed a moderate positive correlation with tumor cell proliferation. Different tumor types exhibited varied degree of correlation, and the correlation was significant in TETs and GSTs. However, our results need further validation by clinical trials with a large sample of different tumor types.