Metabolic tumor volume of primary tumor predicts survival better than T classification in the larynx preservation approach

A convolutional neural network with self-attention for fully automated metabolic tumor volume delineation of head and neck cancer in [Formula: see text]F]FDG PET/CT

PURPOSE

PET-derived metabolic tumor volume (MTV) and total lesion glycolysis of the primary tumor are known to be prognostic of clinical outcome in head and neck cancer (HNC). Including evaluation of lymph node metastases can further increase the prognostic value of PET but accurate manual delineation and classification of all lesions is time-consuming and prone to interobserver variability. Our goal, therefore, was development and evaluation of an automated tool for MTV delineation/classification of primary tumor and lymph node metastases in PET/CT investigations of HNC patients.

METHODS

Automated lesion delineation was performed with a residual 3D U-Net convolutional neural network (CNN) incorporating a multi-head self-attention block. 698 [Formula: see text]F]FDG PET/CT scans from 3 different sites and 5 public databases were used for network training and testing. An external dataset of 181 [Formula: see text]F]FDG PET/CT scans from 2 additional sites was employed to assess the generalizability of the network. In these data, primary tumor and lymph node (LN) metastases were interactively delineated and labeled by two experienced physicians. Performance of the trained network models was assessed by 5-fold cross-validation in the main dataset and by pooling results from the 5 developed models in the external dataset. The Dice similarity coefficient (DSC) for individual delineation tasks and the primary tumor/metastasis classification accuracy were used as evaluation metrics. Additionally, a survival analysis using univariate Cox regression was performed comparing achieved group separation for manual and automated delineation, respectively.

RESULTS

In the cross-validation experiment, delineation of all malignant lesions with the trained U-Net models achieves DSC of 0.885, 0.805, and 0.870 for primary tumor, LN metastases, and the union of both, respectively. In external testing, the DSC reaches 0.850, 0.724, and 0.823 for primary tumor, LN metastases, and the union of both, respectively. The voxel classification accuracy was 98.0% and 97.9% in cross-validation and external data, respectively. Univariate Cox analysis in the cross-validation and the external testing reveals that manually and automatically derived total MTVs are both highly prognostic with respect to overall survival, yielding essentially identical hazard ratios (HR) ([Formula: see text]; [Formula: see text] vs. [Formula: see text]; [Formula: see text] in cross-validation and [Formula: see text]; [Formula: see text] vs. [Formula: see text]; [Formula: see text] in external testing).

CONCLUSION

To the best of our knowledge, this work presents the first CNN model for successful MTV delineation and lesion classification in HNC. In the vast majority of patients, the network performs satisfactory delineation and classification of primary tumor and lymph node metastases and only rarely requires more than minimal manual correction. It is thus able to massively facilitate study data evaluation in large patient groups and also does have clear potential for supervised clinical application.

CT radiomics nomogram predicts pathological response after induced chemotherapy and overall survival in patients with advanced laryngeal cancer: A single-center retrospective study

Purpose

This study aimed to develop a radiomics nomogram to predict pathological response (PR) after induction chemotherapy (IC) and overall survival (OS) in patients with advanced laryngeal cancer (LC).

Methods

This retrospective study included patients with LC (n = 114) who had undergone contrast computerized tomography (CT); patients were randomly assigned to training (n = 81) and validation cohorts (n = 33). Potential radiomics scores were calculated to establish a model for predicting the PR status using least absolute shrinkage and selection operator (LASSO) regression. Multivariable logistic regression analyses were performed to select significant variables for predicting PR status. Kaplan–Meier analysis was performed to assess the risk stratification ability of PR and radiomics score (rad-score) for predicting OS. A prognostic nomogram was developed by integrating radiomics features and clinicopathological characteristics using multivariate Cox regression. All LC patients were stratified as low- and high-risk by the median CT radiomic score, C-index, calibration curve. Additionally, decision curve analysis (DCA) of the nomogram was performed to test model performance and clinical usefulness.

Results

Overall, PR rates were 45.6% (37/81) and 39.3% (13/33) in the training and validation cohorts, respectively. Eight features were optimally selected to build a rad-score model, which was significantly associated with PR and OS. The median OS in the PR group was significantly shorter than that in the non-PR group in both cohorts. Multivariate Cox analysis revealed that volume [hazard ratio, (HR) = 1.43], N stage (HR = 1.46), and rad-score (HR = 2.65) were independent risk factors associated with OS. The above four variables were applied to develop a nomogram for predicting OS, and the DCAs indicated that the predictive performance of the nomogram was better than that of the clinical model.

Conclusion

For patients with advanced LC, CT radiomics score was an independent biomarker for estimating PR after IC. Moreover, the nomogram that incorporated radiomics features and clinicopathological factors performed better for individualized OS estimation.

Clearance Profile of Circulating Tumor Human Papillomavirus DNA During Radiotherapy Predicts Clinical Outcomes in Human Papillomavirus-Related Oropharyngeal Cancer

PURPOSE

This study aimed to examine whether circulating tumor human papillomavirus type 16 (HPV16) DNA (ctHPV16DNA) can help identify patients with locally advanced HPV16-related oropharyngeal squamous cell carcinoma who may benefit from deintensified treatment.

MATERIALS AND METHODS

We serially collected blood samples before, during, and after treatment from 22 patients who received 70 Gy radiotherapy alone and longitudinally quantified ctHPV16DNA using droplet digital polymerase chain reaction. We correlated the clearance profile of ctHPV16DNA with clinical outcomes.

RESULTS

The percentage of patients with detectable ctHPV16DNA decreased after every 10 Gy of radiotherapy. By contrast, the percentage of patients who later developed treatment failure among patients with detectable ctHPV16DNA gradually increased as radiotherapy proceeded, reaching 100% after 60 Gy of radiotherapy. We defined patients with and without detectable ctHPV16DNA after receiving 40 Gy as having slow and rapid clearance profiles, respectively. All 12 patients with a rapid clearance profile remained disease-free after radiotherapy. Of the 10 patients with a slow clearance profile, three had persistent or progressive disease at response evaluation after radiotherapy and one developed distant metastasis during follow-up (ie, four patients experienced treatment failure). The median follow-up for surviving patients was 38.6 months, and the 3-year failure-free survival rates of patients with rapid and slow clearance profiles were 100% and 58%, respectively (P = .02). Neither baseline ctHPV16DNA levels nor metabolic tumor volume was an independent predictor of the pattern of the clearance profile.

CONCLUSION

In patients with HPV16-related oropharyngeal squamous cell carcinoma receiving radiotherapy, a slow ctHPV16DNA clearance profile could prelude unfavorable outcomes. Monitoring ctHPV16DNA is essential for determining the clearance profile, which might help optimize treatment intensity individually.

Prognostic value of MTV and TLG of 18 F-FDG PET in patients with head and neck squamous cell carcinoma: A meta-analysis

BACKGROUND

The current systematic review and meta-analysis explored the value of metabolic tumor volume (MTV) as well as total lesion glycolysis (TLG) in predicting the prognosis of head and neck squamous cell carcinoma (HNSCC) using 18 F-FDG PET parameters.

METHODS

This work identified relevant studies in the English language by searching several electronic databases, like Cochrane Library, EMBASE, and PubMed. In addition, pooled hazard ratios (HRs) were also calculated to analyze whether MTV and TLG were significant in predicting prognosis.

RESULTS

The present study included 15 primary studies involving HNSCC cases. As for the elevated TLG, it attained the pooled HR of 1.85 (95% confidence interval [CI], 1.16-2.94; P = .000; I2 = 78.3%) in predicting overall survival (OS), whereas that for elevated MTV was1.22 (95%CI, 1.09-1.36; P = .000; I2 = 82.4%). Besides, for elevated MTV, it attained the pooled HR of 1.34 (95%CI, 1.15-1.56, P = .000; I2 = 86.0%) in predicting disease-free survival (DFS); while the elevated TLG was related to DFS. Sensitivity analysis confirmed that our results are reliable. As for MTV, the ROC-stratified subgroups for DFS and multivariate analyses-stratified subgroups for OS showed statistically significant differences, with no obvious heterogeneities across different studies. For TLG, other methods-stratified subgroups for OS showed statistically significant differences, with no obvious heterogeneity across different studies.

CONCLUSION

This work indicated that PET/CT is of predictive significance across HNSCC cases. Although the included articles used different methods and recruited HNSCC cases with high clinical heterogeneity; however, our findings confirmed that an elevated MTV can predict the increased risk of side reactions or even death among HNSCC cases and that an elevated TLG can predict a higher death risk.

[Larynx preservation: recommendations for decision-making in T3 laryngeal cancer patients]

BACKGROUND

By today's standard, the optimal treatment of every individual tumor patient is discussed and determined in an interdisciplinary tumor board. According to the new S3 guidelines, larger volume T3 laryngeal cancers which are no longer safely resectable with larynx-sparing surgery are ideal candidates for a larynx preservation approach using primary chemoradiation (pCRT). So far, no clear criteria have been defined under what circumstances primary radiotherapy alone (pRT) might be acceptable in case chemotherapy (CT) is prohibited or in what cases, even in T3, upfront total laryngectomy with risk-adapted adjuvant treatment (TL±a[C]RT) should be recommended.

METHOD

The literature was searched for parameters chosen as criteria for an inclusion in the surgical rather than the conservative arm in non-randomized LP studies or which proved to be significant prognostic markers after conservative treatment. Development of a counselling tool for therapeutic decision making.

RESULTS

Significant prognostic markers were tumor volume (< 3.5 ccm/< 6 ccm vs. 6-12 ccm vs. > 12 ccm), presence and kind of vocal cord fixation (none vs. Succo I/II vs. Succo III/IV), extent of cartilage infiltration (none vs. minimal vs. multiple/gross), nodal status (N0‑1 vs. N2-3), and laryngeal dysfunction (pretreatment necessity of feeding tube or tracheostomy).

CONCLUSION

For T3 laryngeal cancers, pRT could be acceptable when the tumor volume is < 3.5 ccm for glottic and < 6 ccm for supraglottic tumors and there are no further risk factors. pCRT can be regarded as the standard for LP for tumors between 6 ccm and 12 ccm, vocal cord fixation Succo pattern I/II, only minimal cartilage infiltration and a high nodal burden. For tumor > 12 ccm, vocal cord fixation Succo pattern III/IV, gross or multiple cartilage infiltration or clinically relevant laryngeal dysfunction, upfront TL±a[C]RT should be considered.

Utility and limitations of metabolic parameters in head and neck cancer: finding a practical segmentation method

PURPOSE

Although metabolic tumor volume (MTV) and total lesion glycolysis (TLG) have shown good prognostic value in head and neck cancer (HNC), there are still many issues to resolve before their potential application in standard clinical practice. The purpose of this study was to compare the discrimination ability of two relevant segmentation methods in HNC and to evaluate the potential benefit of adding lymph nodes' metabolism (LNM) to the measurements.

METHODS

We retrospectively analyzed a recently published database of 62 patients with HNC treated with chemoradiotherapy. MTV and TLG were measured using an absolute threshold of SUV2.5. Comparison analysis with previously published background-level threshold (BLT) results was done through Concordance index (C-index) in eight prognostic models.

RESULTS

BLT obtained better C-index values in five out of the eight models. The addition of LNM improved C-index values in six of the prognostic models.

CONCLUSION

We found a potential benefit in adding LNM to the main tumor measurements, as well as in using a BLT for MTV segmentation compared to the most commonly used SUV2.5 threshold. Despite its limitations, this study suggests a practical and simple manner to use these parameters in standard clinical practice, aiming to help elaborate a general consensus.

Performance of oral HPV DNA, oral HPV mRNA and circulating tumor HPV DNA in the detection of HPV-related oropharyngeal cancer and cancer of unknown primary

A biomarker that is useful for the detection of human papillomavirus (HPV)‐related oropharyngeal cancer (OPC) and cancer of unknown primary (CUP) is indispensable. We evaluated the diagnostic performance of HPV DNA and mRNA in oral gargle samples and circulating tumor HPV16 DNA (ctHPV16DNA) in blood samples. Oral HPV DNA and mRNA were analyzed using commercially available HPV assays of the GENOSEARCH HPV31 and Aptima, respectively. ctHPV16DNA was analyzed using in‐house droplet digital polymerase chain reaction. Seventy‐four patients with OPC and eight patients with CUP were included. The sensitivity and specificity of oral HPV DNA, oral HPV mRNA, and ctHPV16DNA were 82% (95% confidence interval [CI] = 66‐92) and 100% (95% CI = 88‐100), 85% (95% CI = 69‐94) and 94% (95% CI = 73‐100), and 93% (95% CI = 81‐99) and 97% (95% CI = 84‐100), respectively, for HPV16‐related OPC, while those were 20% (95% CI = 1‐72) and 100% (95% CI = 3‐100), 0% (95% CI = 0‐52) and 100% (95% CI = 3‐100), and 100% (95% CI = 54‐100) and 100% (95% CI = 16‐100), respectively, for HPV16‐related CUP. The sensitivity of ctHPV16DNA for HPV16‐related OPC was higher than that of oral biomarkers, though the difference was not statistically significant. ctHPV16DNA remarkably correlated with the anatomic extent of disease, total metabolic tumor volume and HPV16 copy number per tumor genome in patients with HPV16‐related OPC/CUP, whereas oral biomarkers did not. In conclusion, ctHPV16DNA is a potentially promising biomarker for HPV16‐related OPC, while further studies are required for HPV16‐related CUP.

What's new?

A minimally‐invasive biomarker that allows the detection of human papillomavirus (HPV)‐related oropharyngeal cancer and cancer of unknown primary is indispensable. Here, the authors show that circulating tumour HPV DNA (ctHPVDNA) correlates with the tumour burden and HPV copy number per tumour genome in HPV‐related oropharyngeal cancer and cancer of unknown primary. Neither oral HPV DNA nor mRNA exhibits such a correlation. ctHPVDNA outperforms oral HPV DNA and mRNA in detecting HPV‐related oropharyngeal cancer and in distinguishing HPV‐related cancer of unknown primary from HPV‐unrelated cancers. ctHPVDNA emerges as a potentially useful biomarker for HPV‐related oropharyngeal cancer and cancer of unknown primary.

Functional Larynx Preservation in Patients With Locally Advanced Squamous Cell Carcinoma of the Larynx and Hypopharynx Treated With Induction Chemotherapy vs. Concurrent Chemoradiation Alone

Objectives

Chemoradiation therapy (CRT) has been established as a standard treatment for locally advanced hypopharynx/larynx squamous cell carcinoma (SCC) but the role of induction chemotherapy (IC) remains unclear. The primary outcome of this study is to determine whether functional larynx-preservation survival (FLPS) is improved with the addition of IC in these patients. Secondary outcomes were overall survival (OS), progression-free survival (PFS), distant metastasis-free survival (DMFS), and laryngectomy rates.

Methods

Records for patients with AJCC 8th edition clinical stage III-IVB laryngeal and hypopharyngeal SCC treated with CRT +/- IC from 2005-2019 were reviewed. FLPS was defined as time until death, progression, laryngectomy, or non-functional larynx. Kaplan-Meier curves were generated for FLPS, OS, PFS, and DMFS. Outcomes were compared using the stratified log-rank test. Laryngectomy rates were compared using Fisher’s exact test.

Results

We included 52 patients with laryngeal and 38 with hypopharyngeal SCC (n=90); 19 patients with laryngeal SCC and 19 with hypopharyngeal SCC received IC (median three cycles). There were no differences in the three-year FLPS (61% vs 67.8%; p=0.88), OS (73.9% vs 86.2%; p=0.42), PFS (53.6% vs 62.6%; p=0.44), or DMFS (65.2% vs 71.5%, p= 0.85) between patients who did and did not receive IC all patients. Laryngectomy rates did not differ with and without IC (18.4 % vs 7.7%; p=0.19).

Conclusion

In this study of advanced laryngeal and hypopharyngeal SCC, IC did not improve three-year FLPS, OS, PFS, or laryngectomy rates compared to CRT alone. A large prospective series would provide a more robust understanding of the role of IC in this group of patients. 

Adding value to tumor staging in head and neck cancer: The role of metabolic parameters as prognostic factors

BACKGROUND

Validated biomarkers in head and neck squamous cell carcinoma (HNSCC) are scarce.

METHODS

We retrospectively analyzed 62 patients with HNSCC treated with radiotherapy +/- concurrent chemotherapy. Pretreatment metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were measured in a ¹⁸ F-FDG positron emission tomography using a liver dependent standardized uptake value threshold. Cox regression analyses were performed to find associations with disease-free survival (DFS) and overall survival (OS).

RESULTS

High values of MTV (>37 ml) were independently associated with a worse DFS (hazard ratio [HR] = 3.45; 95% confidence interval [CI], 1.52-7.84) and OS (HR = 3.27; 95% CI, 1.41-7.57). Similar results were found for high values of TLG (>247 g) for DFS (HR = 3.32; 95% CI, 1.44-7.65) and OS (HR = 3.42; 95% CI, 1.45-8.07).

CONCLUSIONS

MTV and TLG can be considered as independent prognostic factors for DFS and OS in patients with HNSCC. Considering how easily obtainable they are, they may be useful for predicting clinical outcomes in these patients.

CMBD: a manually curated cancer metabolic biomarker knowledge database

The pathogenesis of cancer is influenced by interactions among genes, proteins, metabolites and other small molecules. Understanding cancer progression at the metabolic level is propitious to the visual decoding of changes in living organisms. To date, a large number of metabolic biomarkers in cancer have been measured and reported, which provide an alternative method for cancer precision diagnosis, treatment and prognosis. To systematically understand the heterogeneity of cancers, we developed the database CMBD to integrate the cancer metabolic biomarkers scattered over literatures in PubMed. At present, CMBD contains 438 manually curated relationships between 282 biomarkers and 76 cancer subtypes of 18 tissues reported in 248 literatures. Users can access the comprehensive metabolic biomarker information about cancers, references, clinical samples and their relationships from our online database. As case studies, pathway analysis was performed on the metabolic biomarkers of breast and prostate cancers, respectively. 'Phenylalanine, tyrosine and tryptophan biosynthesis', 'phenylalanine metabolism' and 'primary bile acid biosynthesis' were identified as playing key roles in breast cancer. 'Glyoxylate and dicarboxylate metabolism', 'citrate cycle (TCA cycle)', and 'alanine, aspartate and glutamate metabolism' have important functions in prostate cancer. These findings provide us with an understanding of the metabolic pathway of cancer initiation and progression. Database URL: http://www.sysbio.org.cn/CMBD/.

Response Evaluation Criteria in Solid Tumors (RECIST) and PET Response Criteria in Solid Tumors (PERCIST) for response evaluation of the neck after chemoradiotherapy in head and neck squamous cell carcinoma

BACKGROUND

An optimal approach to imaging assessment of neck after chemoradiotherapy must be established to avoid unnecessary neck dissection.

METHODS

We retrospectively examined 101 patients and compared between Response evaluation criteria in solid tumors (RECIST), PET response criteria in solid tumors (PERCIST), and positron emission tomography/computed tomography (PET/CT) qualitative assessment.

RESULTS

PERCIST was superior to RECIST in positive predictive value (PPV; 47% vs. 36%), with equivalent negative predictive value (NPV; 78%). Only 3 of 15 patients with incomplete responses on either RECIST or PERCIST alone had regional treatment failure, and the combination of RECIST and PERCIST improved PPV (55%) without reducing NPV. This combination yielded the highest hazard ratio of regional treatment failure. The combination of RECIST and PET/CT qualitative assessment also improved PPV (50%). In human papillomavirus (HPV)-related oropharyngeal cancer, NPV was 100% across the imaging assessments, while PPV was poor (14%-33%).

CONCLUSIONS

Combining RECIST and PERCIST might optimize decision making in neck management after chemoradiotherapy. HPV status would affect the accuracy of response evaluation.

Prognostic significance of semi-quantitative FDG-PET parameters in stage I non-small cell lung cancer treated with carbon-ion radiotherapy

Purpose

Prognostic significance of volumetric ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computer tomography (PET/CT) parameters in carbon-ion radiotherapy (C-ion RT) treated stage I non-small cell lung cancer, and need of histology-wise separate cut-off values for risk stratification were assessed.

Methods

Thirty-nine patients (29 men and 10 women, 71.9 ± 8.3 years) who underwent FDG PET/CT examinations before C-ion RT were retrospectively evaluated. FDG-PET parameters: standardized uptake values (SUVmax, SUVpeak, and SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG), and clinicopathological variables were assessed for prognosis using Cox proportional hazards regression analysis. Mann-Whitney test compared medians of significant parameters between adenocarcinoma (AC) and squamous cell carcinoma (SCC), and Kaplan-Meier curves were plotted for median-based low- and high-risk groups.

Results

Median follow-up period was 44.8 months. 1/2/3-year overall survival (OS), progression-free survival (PFS) and local control (LC) rates were 94.9/84.3/70.8, 82.1/69.2/58.4 and 97.3/85.7/82.3%. Multivariate analysis revealed age (hazard ratio, HR: 1.09; 95% confidence interval, CI: 1.0–1.19, p < 0.05) and MTV (HR 4.83, 95% CI 1.21–19.27, p < 0.03) predicted OS, and only MTV predicted PFS (HR 5.3, CI 1.32–21.35, p < 0.02) independently. Compared with AC, SCC had higher MTV (median, 6.625cm³ vs 0.2 cm³, p < 0.01). Single MTV cut-off based on overall cohort was insignificant in SCC for PFS (p > 0.02); separate cut-offs of MTV, 0.2 cm³ for AC (p < 0.03) and 6.625 cm³ for SCC (p < 0.05) were relevant.

Conclusion

Among all FDG PET/CT parameters, only MTV beared prognostic ability for stage I NSCLC treated with C-ion RT, and its histological variation may need consideration for risk-adapted therapeutic management.

Metabolic tumor volume of metastatic lymph nodes and survival after total laryngectomy in laryngeal and hypopharyngeal cancer

OBJECTIVES

The prognostic value of metabolic tumor volume (MTV) in locally advanced laryngeal or hypopharyngeal cancer is established in the setting of chemoradiotherapy, while it remains unknown in the setting of upfront total laryngectomy.

MATERIALS AND METHODS

We retrospectively analyzed 88 patients receiving total laryngectomy and neck dissection, using Cox regression models.

RESULTS AND CONCLUSION

Variables related to metastatic lymph node were associated with overall survival, whereas those related to primary tumor were not. In multivariable models, MTV of metastatic lymph nodes (N-MTV) as a continuous variable (Akaike's information criterion (AIC), 277.5) was equivalent to pathological nodal status (AIC, 278.2; P = 0.40), and superior to pathological nodal classification as an ordinal variable (AIC, 281.4; P < 0.05) in ability of predicting death. The risk of death was increased by 1.2-fold (95% confidence interval (CI), 1.0-1.4; P = 0.03) every 10-ml increment of N-MTV, while patients with pN+ disease were at a higher risk of death by 2.9-fold (95% CI, 1.0-12.2; P < 0.05) compared with patients with pN0 disease. Using recursive partitioning analysis (RPA), we classified the patients as having a low, intermediate, or high risk of death on the basis of N-MTV and extranodal extension (ENE). This RPA classification system exhibited greater concordance with overall survival than the classification considering pathological nodal status and ENE (AIC, 275.8 versus 281.4; P = 0.02). In the setting of upfront total laryngectomy, N-MTV is a critical predictor of mortality. A staging system in which N-MTV is incorporated may better inform adjuvant treatment decisions.

Prognostic significance of pretreatment 18F-fluorodeoxyglucose positron emission tomography evaluation using metabolic tumor volume of the primary tumor and lymph nodes in advanced hypopharyngeal cancer

BACKGROUND

The purpose of this study was to retrospectively evaluate the usefulness of pretreatment positron emission tomography (PET) using metabolic tumor volume (MTV) of the primary tumor and lymph nodes in advanced hypopharyngeal cancer.

METHODS

From June 2007 to December 2015, consecutive patients with advanced hypopharyngeal cancer who underwent PET and were treated with definitive radiation therapy were retrospectively reviewed.

RESULTS

A total of 61 patients were eligible for this study. On multivariate analysis, MTV of the primary tumor (MTV-T) was significantly related to the local control rate and overall survival (OS) (P = .036 and .012, respectively). In patients with lower MTV-T, MTV of metastatic lymph nodes (MTV-N) was significantly related to disease-specific survival and OS (P = .012 and .017, respectively).

CONCLUSION

MTV-T is a significant predictor in patients with advanced hypopharyngeal cancer, and MTV-N is also significant in patients with lower MTV-T.

What is the prognostic impact of FDG PET in locally advanced head and neck squamous cell carcinoma treated with concomitant chemo-radiotherapy? A systematic review and meta-analysis

PURPOSE

Evidence is conflicting on the prognostic value of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in head and neck squamous cell carcinoma. The aim of our study was to determine the impact of semiquantitative and qualitative metabolic parameters on the outcome in patients managed with standard treatment for locally advanced disease.

METHODS

A systematic review of the literature was conducted. A meta-analysis was performed of studies providing estimates of relative risk (RR) for the association between semiquantitative metabolic parameters and efficacy outcome measures.

RESULTS

The analysis included 25 studies, for a total of 2,223 subjects. The most frequent primary tumour site was the oropharynx (1,150/2,223 patients, 51.7%). According to the available data, the majority of patients had stage III/IV disease (1,709/1,799, 94.9%; no information available in four studies) and were treated with standard concurrent chemoradiotherapy (1,562/2,009 patients, 77.7%; only one study without available information). A total of 11, 8 and 4 independent studies provided RR estimates for the association between baseline FDG PET metrics and overall survival (OS), progression-free survival (PFS) and locoregional control (LRC), respectively. High pretreatment metabolic tumour volume (MTV) was significantly associated with a worse OS (summary RR 1.86, 95% CI 1.08-3.21), PFS (summary RR 1.81, 95% CI 1.14-2.89) and LRC (summary RR 3.49, 95% CI 1.65-7.35). Given the large heterogeneity (I2 > 50%) affecting the summary measures, no cumulative threshold for an unfavourable prognosis could be defined. No statistically significant association was found between SUVmax and any of the outcome measures.

CONCLUSION

FDG PET has prognostic relevance in the context of locally advanced head and neck squamous cell carcinoma. Pretreatment MTV is the only metabolic variable with a significant impact on patient outcome. Because of the heterogeneity and the lack of standardized methodology, no definitive conclusions on optimal cut-off values can be drawn.

Metabolic tumor volume of primary tumor predicts survival better than T classification in the larynx preservation approach

We aimed to determine whether pretreatment metabolic tumor volume of the primary tumor (T-MTV) or T classification would be a better predictor of laryngectomy-free survival (LFS) and overall survival (OS) after chemoradiotherapy in patients with locally advanced laryngeal or hypopharyngeal cancer requiring total laryngectomy. We analyzed 85 patients using a Cox proportional hazards model and evaluated its usefulness by Akaike's information criterion. A T-MTV cut-off value was determined by time-dependent receiver operating characteristic curve analysis. Interobserver reliability for measuring T-MTV was estimated by the intraclass correlation coefficient (ICC). After adjustment for covariables, T-MTV, irrespective of whether a continuous or dichotomized variable, and T classification remained independent predictors of LFS and OS. Large T-MTV (>28.7 mL) was associated with inferior LFS (hazard ratio [HR], 4.16; 95% confidence interval [CI], 1.97-8.70; P = 0.0003) and inferior OS (HR, 3.18; 95% CI, 1.47-6.69; P = 0.004) compared with small T-MTV (≤28.7 mL). The T-MTV model outperformed the T classification model in predicting LFS and OS (P = 0.007 and 0.01, respectively). Three-year LFS and OS rates for patients with small versus large T-MTV were 68% vs 9% (P < 0.0001) and 77% vs 25% (P < 0.0001), respectively, whereas those for patients with T2-T3 versus T4a were 61% vs 31% (P = 0.003) and 71% vs 48% (P = 0.10), respectively. ICC was 0.99 (95% CI, 0.99-1.00). Given the excellent interobserver reliability, T-MTV is better than T classification to identify patients who would benefit from the larynx preservation approach.