Current oncologic concepts and emerging techniques for imaging of head and neck squamous cell cancer

Targeting fibroblast activation protein in newly diagnosed squamous cell carcinoma of the oral cavity - initial experience and comparison to [18F]FDG PET/CT and MRI

Purpose

While [¹⁸F]-fluorodeoxyglucose ([¹⁸F]FDG) is the standard for positron emission tomography/computed tomography (PET/CT) imaging of oral squamous cell carcinoma (OSCC), diagnostic specificity is hampered by uptake in inflammatory cells such as neutrophils or macrophages. Recently, molecular imaging probes targeting fibroblast activation protein α (FAP), which is overexpressed in a variety of cancer-associated fibroblasts, have become available and might constitute a feasible alternative to FDG PET/CT.

Methods

Ten consecutive, treatment-naïve patients (8 males, 2 females; mean age, 62 ± 9 years) with biopsy-proven OSCC underwent both whole-body [¹⁸F]FDG and [⁶⁸Ga]FAPI-04 (FAP-directed) PET/CT for primary staging prior to tumor resection and cervical lymph node dissection. Detection of the primary tumor, as well as the presence and number of lymph node and distant metastases was analysed. Intensity of tracer accumulation was assessed by means of maximum (SUV_max) and peak (SUV_peak) standardized uptake values. Histological work-up including immunohistochemical staining for FAP served as standard of reference.

Results

[¹⁸F]FDG and FAP-directed PET/CT detected all primary tumors with a SUV_max of 25.5 ± 13.2 (FDG) and 20.5 ± 6.4 (FAP-directed) and a SUV_peak of 16.1 ± 10.3 ([¹⁸F]FDG) and 13.8 ± 3.9 (FAP-directed), respectively. Regarding cervical lymph node metastases, FAP-directed PET/CT demonstrated comparable sensitivity (81.3% vs. 87.5%; P = 0.32) and specificity (93.3% vs. 81.3%; P = 0.16) to [¹⁸F]FDG PET/CT. FAP expression on the cell surface of cancer-associated fibroblasts in both primary lesions as well as lymph nodes metastases was confirmed in all samples.

Conclusion

FAP-directed PET/CT in OSCC seems feasible. Future research to investigate its potential to improve patient staging is highly warranted.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-021-05422-z.

Accuracy of 18-F Fluorodeoxyglucose Positron Emission Tomographic/Computed Tomographic Imaging in Primary Staging of Squamous Cell Carcinoma of the Oral Cavity

IMPORTANCE

Squamous cell carcinoma (SCC) of the oral cavity is one of the most common tumor entities worldwide. Precise initial staging is necessary to determine a diagnosis, treatment, and prognosis.

OBJECTIVE

To examine the diagnostic accuracy of preoperative 18-F fluorodeoxyglucose (FDG) positron emission tomographic/computed tomographic (PET/CT) imaging in detecting cervical lymph node metastases.

DESIGN, SETTING, AND PARTICIPANTS

This prospective diagnostic study was performed at a single tertiary reference center between June 1, 2013, and January 31, 2016. Data were analyzed from April 7, 2018, through May 31, 2019. Observers of the FDG PET/CT imaging were blinded to patients' tumor stage. A total of 150 treatment-naive patients with clinical suspicion of SCC of the oral cavity were enrolled.

EXPOSURES

All patients underwent FDG PET/CT imaging before local tumor resection with selective or complete neck dissection.

MAIN OUTCOMES AND MEASURES

The accuracy of FDG PET/CT in localizing primary tumor, lymph node, and distant metastases was tested. Histopathologic characteristics of the tissue samples served as the standard of reference.

RESULTS

Of the 150 patients enrolled, 135 patients (74 [54.8%] men) with a median age of 63 years (range, 23-88 years) met the inclusion criteria (histopathologically confirmed primary SCC of the oral cavity/level-based histopathologic assessment of the resected lymph nodes). Thirty-six patients (26.7%) in the study cohort had neck metastases. Use of FDG PET/CT detected cervical lymph node metastasis with 83.3% sensitivity (95% CI, 71.2%-95.5%) and 84.8% specificity (95% CI, 77.8%-91.9%) and had a negative predictive value of 93.3% (95% CI, 88.2%-98.5%). The specificity was higher than for contrast-enhanced cervical CT imaging (67.0%; 95% CI, 57.4%-76.7%; P < .01) and cervical magnetic resonance imaging (62.6%; 95% CI, 52.7%-72.6%; P < .001). Ipsilateral lymph node metastasis in left- or right-sided primary tumor sites was detected with 78.6% sensitivity (95% CI, 63.4%-93.8%) and 83.1% specificity (95% CI, 75.1%-91.2%), and contralateral metastatic involvement was detected with 66.7% sensitivity (95% CI, 28.9%-100.0%) and 98.6% specificity (95% CI, 95.9%-100.0%). No distant metastases were observed.

CONCLUSIONS AND RELEVANCE

In this study, FDG PET/CT imaging had a high negative predictive value in detecting cervical lymph node metastasis in patients with newly diagnosed, treatment-naive SCC of the oral cavity. Routine clinical use of FDG PET/CT might lead to a substantial reduction of treatment-related morbidity in most patients.

Utility of 3-Month Surveillance F-18 FDG PET/CT in Surgically Resected Oral Squamous Cell Carcinoma

OBJECTIVES

To evaluate the performance of surveillance F-18 fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) 1 year after imaging in oral squamous cell carcinoma (OSCC) patients treated with definitive surgery and adjuvant (chemo)radiotherapy (RT).

METHODS AND MATERIALS

Surveillance PET/CT accuracy was retrospectively evaluated in OSCC patients receiving surgical resection and (chemo)RT. Pathologic risk factors were assessed for influence on accuracy of the post-RT PET/CT.

RESULTS

Fifty-four patients with median follow-up of 3.8 years met inclusion criteria. A PET/CT obtained a median of 3.4 months after RT revealed 11 (20.4%) instances of true disease recurrence: 4 locoregional alone, 6 distant alone, and 1 patient with locoregional and distant disease. Locoregional detection sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 55.6%, 75.0%, 33.3%, and 88.2%, respectively. For distant recurrence, the respective values were 100%, 95.2%, 77.8%, and 100%. Absence of bone invasion, absence of pT4 disease, and disease within the tongue were independently associated with higher sensitivity ( P = .048). Perineural invasion was associated with increased specificity ( P = .027), and tumor location in the tongue was associated with a higher PPV ( P = .007) on surveillance PET/CT.

CONCLUSIONS

Post-RT PET/CT accuracy information for surgically managed OSCC patients demonstrates significant associations with pathologic factors.

Primary tumor-associated expression of CXCR4 predicts formation of local and systemic recurrency in head and neck squamous cell carcinoma

Objectives

Despite modern treatment regimens, overall survival in head and neck squamous cell carcinomas (HNSCC) is less than 50% due to local and systemic disease recurrency. The current study aims to identify molecular markers in primary tumor specimens that predict the risk for local and systemic recurrency at the time of initial diagnosis.

Methods

The study included clinic-pathological data of 1,057 HNSCC. MMP2/9, TIMP1/2, CXCR4, and CXCL12 immunohistochemistry was done in 150 randomly selected specimens. For statistics, we employed Chi square, Fisher exact, and Student's t-test. Overall survival (OS) was calculated by Kaplan–Meier and log-rank test. Prognostic variables were subsequently evaluated by Cox regression for forward selection.

Results

CXCR4 positive specimens demonstrated a significant increased risk for tumor recurrency associated death (rT: HR 10.07; p=0.001 / rN: HR 5.04; p=0.013 / rM: HR 2.49; p=0.029) when compared with their unaltered counterparts. Expression of MMP9, TIMP2, CXCR4, and CXCL12 was significantly increased in distant metastasized patients (p<0.0001) and showed significant cross-correlation. In addition, CXCR4 positivity was associated with an increased risk to die due to enhanced T or N status (T1/2 vs. T3/4: HR 5.78; p=0.017; N0 vs. N+: HR 5.18; p=0.033).

Conclusion

CXCR4 positivity in tumor samples at initial diagnosis were associated with reduced overall survival, in particular with respect to increasing T/N status, local and systemic recurrency.

18F-Fluoromisonidazole in tumor hypoxia imaging

Hypoxia is a common feature of solid tumors that is closely associated with radiotherapy and chemotherapy resistance, metastasis and tumors prognosis. Thus, it is important to assess hypoxia in tumors for estimating prognosis and selecting appropriate treatment procedures. ¹⁸F-Fluoromisonidazole positron emission tomography (¹⁸F-FMISO PET) has been widely used to visualize tumor hypoxia in a comprehensive and noninvasive way, both in the clinical and preclinical settings. Here we review the concept, mechanisms and detection methods of tumor hypoxia. Furthermore, we discuss the correlation between ¹⁸F-FMISO PET and other detection methods, current applications of ¹⁸F-FMISO PET and the development prospects of this imaging technology.

Role of Computed Tomography (CT) in Localisation and Characterisation of Suprahyoid Neck Masses

Background

Suprahyoid neck lesions are difficult to assess only by means of clinical inspection and therefore imaging techniques are required to precisely evaluate suprahyoid neck spaces. The aim of this study was to evaluate the distinctive role of computed tomography in the assessment of anatomical source and pathological type of masses involving the suprahyoid neck spaces.

Material/Methods

Sixty patients presenting with suprahyoid neck masses underwent computed tomography of the neck. The CT findings were correlated with histopathological findings and a final diagnosis was made.

Results

Overall, male preponderance was seen except in the case of parotid space lesions where female predominance was seen. The most common aetiology was squamous cell carcinoma and the majority of cases (30%) were seen in patients aged 41–50 years. The majority of lesions were found in the pharyngeal mucosal space (n=16) with squamous cell carcinoma being the most common pathology. In the parotid space, pleomorphic adenoma and in the prestyloid parapharyngeal space, squamous cell carcinoma were the most common lesions, respectively. In the retropharyngeal space, an equal incidence of malignant and inflammatory aetiologies was seen. Abscesses were the most common lesions in the prevertebral space. The pleomorphic adenoma was the most common benign tumour and was also the second most common tumour in the suprahyoid neck spaces. CT had an excellent correlation with histopathological findings with sensitivity of 96.4%, specificity of 100%, positive predictive value of 100% and a negative predictive value of 91.67%.

Conclusions

Computed tomography definitely has a major role to play in the evaluation of suprahyoid neck masses as it has an excellent correlation with post-operative histopathological diagnosis.

Enhanced Control of Bladder-Associated Tumors Using Shrimp Anti-Lipopolysaccharide Factor (SALF) Antimicrobial Peptide as a Cancer Vaccine Adjuvant in Mice

Shrimp anti-lipopolysaccharide factor (SALF) is an antimicrobial peptide with reported anticancer activities, such as suppression of tumor progression. In this study, we prepared a potential cancer vaccine comprised of SALF in conjunction with the cell lysate of inactivated murine bladder carcinoma cells (MBT-2), and evaluated its efficacy in a mouse tumor model. Our study shows that SALF added to cell culture media inhibits growth progression of MBT-2, and that SALF together with inactivated MBT-2 lysate elevates the level of inflammasome activity, and modulates the levels of IL-1β, MCP-1, IL-6, IL-12, and TNF-α in mouse macrophages. Immunization of 7, 14, and 21 day-old mice with the vaccine prevented growth of MBT-2 cell-mediated tumors. The vaccine was found to enhance expression of T-cell, cytotoxic T cells, and NK cells in the immunized mice groups. Recruitment of macrophages, T-helper cells, and NK cells was enhanced, but levels of VEGF were decreased in immunized mice. This report provides empirical evidence that our SALF as vaccine adjuvant enhances antitumor immunity in mice.

Assessment of an Advanced Monoenergetic Reconstruction Technique in Dual-Energy Computed Tomography of Head and Neck Cancer

OBJECTIVES

To define optimal keV settings for advanced monoenergetic (Mono+) dual-energy computed tomography (DECT) in patients with head and neck squamous cell carcinoma (SCC).

METHODS

DECT data of 44 patients (34 men, mean age 55.5 ± 16.0 years) with histopathologically confirmed SCC were reconstructed as 40, 55, 70 keV Mono + and M_0.3 (30 % 80 kV) linearly blended series. Attenuation of tumour, sternocleidomastoid muscle, internal jugular vein, submandibular gland, and noise were measured. Three radiologists with >3 years of experience subjectively assessed image quality, lesion delineation, image sharpness, and noise.

RESULTS

The highest lesion attenuation was shown for 40 keV series (248.1 ± 94.1 HU), followed by 55 keV (150.2 ± 55.5 HU; P = 0.001). Contrast-to-noise ratio (CNR) at 40 keV (19.09 ± 13.84) was significantly superior to all other reconstructions (55 keV, 10.25 ± 9.11; 70 keV, 7.68 ± 6.31; M_0.3, 5.49 ± 3.28; all P < 0.005). Subjective image quality was highest for 55 keV images (4.53; κ = 0.38, P = 0.003), followed by 40 keV (4.14; κ = 0.43, P < 0.001) and 70 keV reconstructions (4.06; κ = 0.32, P = 0.005), all superior (P < 0.004) to linear blending M_0.3 (3.81; κ = 0.280, P = 0.056).

CONCLUSIONS

Mono + DECT at low keV levels significantly improves CNR and subjective image quality in patients with head and neck SCC, as tumour CNR peaks at 40 keV, and 55 keV images are preferred by observers.

KEY POINTS

• Mono + DECT combines increased contrast with reduced image noise, unlike linearly blended images. • Mono + DECT imaging allows for superior CNR and subjective image quality. • Head and neck tumour contrast-to-noise ratio peaks at 40 keV. • 55 keV images are preferred over all other series by observers.

Low-tube-voltage 80-kVp neck CT: evaluation of diagnostic accuracy and interobserver agreement

BACKGROUND AND PURPOSE

Low-tube-voltage acquisition has been shown to facilitate substantial dose savings for neck CT with similar image contrast compared with standard 120-kVp acquisition. However, its potential for the detection of neck pathologies is uncertain. Our aim was to evaluate the effects of low-tube-voltage 80-kV(peak) acquisitions for neck CT on diagnostic accuracy and interobserver agreement.

MATERIALS AND METHODS

Three radiologists individually analyzed 80-kVp and linearly blended 120-kVp image series of 170 patients with a variety of pathologies who underwent dual-energy neck CT. Reviewers were unblinded to the clinical indication for CT but were otherwise blinded to any other data or images and were asked to state a final main diagnosis. Findings were compared with medical record charts, CT reports, and pathology results. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for each observer. Interobserver agreement was evaluated by using intraclass correlation coefficients.

RESULTS

Diagnoses were grouped as squamous cell carcinoma-related (n = 107, presence/absence of primary/recurrent squamous cell carcinoma), lymphoma-related (n = 40, presence/absence of primary/recurrent lymphoma), and benign (n = 23, eg, abscess). Cumulative sensitivity, specificity, positive predictive value, and negative predictive value for 80-kVp and blended 120-kVp images were 94.8%, 93.0%, 95.9%, and 91.1%, respectively. Results were also consistently high for squamous cell carcinoma-related (94.8%/95.3%, 89.1%/89.1%, 94.3%/94.4%, 90.1%/91.0%) and lymphoma-related (95.0%, 100.0%, 100.0%, 95.2%) 80-kVp/120-kVp image series. Global interobserver agreement was almost perfect (intraclass correlation coefficient, 0.82, 0.80; 95% CI, 0.76-0.74, 0.86-0.85). Calculated dose-length product was reduced by 48% with 80-kVp acquisitions compared with the standard 120-kVp scans (135.5 versus 282.2 mGy × cm).

CONCLUSIONS

Low-tube-voltage 80-kVp CT of the neck provides sufficient image quality with high diagnostic accuracy in routine clinical practice and has the potential to substantially decrease radiation exposure.

PET/MRI and PET/CT in follow-up of head and neck cancer patients

PURPOSE

Positron emission tomography (PET)/MRI combines the functional ability of PET and the high soft tissue contrast of MRI. The aim of this study was to assess contrast-enhanced (ce)PET/MRI compared to cePET/CT in patients with suspected recurrence of head and neck cancer (HNC).

METHODS

Eighty-seven patients underwent sequential cePET/CT and cePET/MRI using a trimodality PET/CT-MRI set-up. Diagnostic accuracy for the detection of recurrent HNC was evaluated using cePET/CT and cePET/MRI. Furthermore, image quality, presence of unclear (18)F-fluorodeoxy-D-glucose (FDG) findings of uncertain significance and the diagnostic advantages of use of gadolinium contrast enhancement were analysed.

RESULTS

cePET/MRI showed no statistically significant difference in diagnostic accuracy compared to cePET/CT (91.5 vs 90.6%). Artefacts' grade was similar in both methods, but their location was different. cePET/CT artefacts were primarily located in the suprahyoid area, while on cePET/MRI, artefacts were more equally distributed among the supra and infrahyoid neck regions. cePET/MRI and cePET/CT showed 34 unclear FDG findings; of those 11 could be solved by cePET/MRI and 5 by cePET/CT. The use of gadolinium in PET/MRI did not yield higher diagnostic accuracy, but helped to better define tumour margins in 6.9% of patients.

CONCLUSION

Our data suggest that cePET/MRI may be superior compared to cePET/CT to specify unclear FDG uptake related to possible tumour recurrence in follow-up of patients after HNC. It seems to be the modality of choice for the evaluation of the oropharynx and the oral cavity because of a higher incidence of artefacts in cePET/CT in this area mainly due to dental implants. However, overall there is no statistically significant difference.