The ability of post-chemoradiotherapy DWI ADCmean and 18F-FDG SUVmax to predict treatment outcomes in head and neck cancer: impact of human papilloma virus oropharyngeal cancer status

OBJECTIVES

To evaluate the ability of post-chemo-radiotherapy (CRT) diffusion-weighted-MRI apparent diffusion coefficient (ADCmean) and 18F-FDG PET maximum standardized uptake value (SUVmax) to predict disease-free survival (DFS) in head and neck squamous cell carcinoma (HNSCC), and to determine whether this ability is influenced by human papillomavirus oropharyngeal cancer (HPV-OPC) status.

METHODS

This prospective cohort observational study included 65 participants (53 male, mean ± SD age 59.9 ± 7.9 years, 46 HPV-OPC) with stage III or IV HNSCC. Primary tumour and nodal ADCmean (pre-treatment, 6- and 12-weeks post-CRT) and SUVmax (12-weeks post-CRT) were measured. Variables were compared with 2-year DFS (independent t-test/Mann-Whitney test) and overall DFS (Cox regression), before and after accounting for HPV-OPC status. Variables were also compared between HPV-OPC and other HNSCC subgroups after stratifying for DFS.

RESULTS

Absolute post-CRT ADCmean values predicted 2-year DFS and overall DFS for all participants (p = 0.03/0.03, 6-week node; p = 0.02/0.03 12-week primary tumour) but not in the HPV-OPC subgroup. In participants with DFS, percentage interval changes in primary tumour ADCmean at 6- and 12-weeks were higher in HPV-OPC than other HNSCC (p = 0.01, 6 weeks; p = 0.005, 12 weeks). The 12-week post-CRT SUVmax did not predict DFS.

CONCLUSION

Absolute post-CRT ADCmean values predicted DFS in HNSCC but not in the HPV-OPC subgroup. Amongst participants with DFS, post-CRT percentage interval changes in primary tumour ADCmean were significantly higher in HPV-OPC than in other HNSCC. Knowledge of HPV-OPC status is crucial to the clinical utilisation of post-CRT DWI-MRI for the prediction of outcomes.

Palatine tonsil SUVmax on FDG PET-CT as a discriminator between benign and malignant tonsils in patients with and without head and neck squamous cell carcinoma of unknown primary

AIM

To analyse the maximum standardised uptake value (SUVmax) ratio between tonsils in patients with and without tonsillar carcinoma to determine useful diagnostic thresholds.

MATERIALS AND METHODS

Positron-emission tomography (PET)/computed tomography (CT) examinations of patients with suspected head and neck squamous cell carcinoma (SCC) and controls from April 2013 to September 2016 were reviewed retrospectively. Tonsillar SUVmax ratios (ipsilateral/contralateral for malignant tonsils, maximum/minimum for patients without [controls]) were calculated and used to construct a receiver operating characteristic (ROC) curve.

RESULTS

Twenty-five patients had tonsillar carcinoma (mean SUVmax ratio of 2, range 0.89-5.4) and 86 patients acted as controls (mean SUVmax ratio of 1.1, range 1-1.5). Using the ROC, the most accurate SUVmax ratio for identifying malignancy was >1.2 (77% sensitivity, 86% specificity). A potentially more clinically useful SUVmax ratio is ≥1.6 with 62% sensitivity and 100% specificity.

CONCLUSION

An SUVmax ratio between tonsils of ≥1.6 is highly suspicious for SCC and could be used to direct site of biopsy. Some malignant tonsils had normal FDG uptake; therefore, PET/CT should not be used to exclude tonsillar cancer. Minor asymmetrical uptake is frequently seen in non-malignant tonsils and does not necessarily require further investigation. Due to the single centre nature of this study and the recognised variation in SUV measurements between PET scans, other centres may need to develop their own cut-offs.

What is the quality of economic evaluations of non-drug therapies? A systematic review and critical appraisal of economic evaluations of radiotherapy for cancer

BACKGROUND

Breast, cervical and colorectal cancers are the three most frequent cancers in women, while lung, prostate and colorectal cancers are the most frequent in men. Much attention has been given to the economic evaluation of pharmaceuticals for treatment of cancer by the National Institute for Health and Care Excellence (NICE) in the UK and similar authorities internationally, while economic analysis developed for other types of anti-cancer interventions, including radiotherapy and surgery, are less common.

OBJECTIVES

Our objective was to review methods used in published cost-effectiveness studies evaluating radiotherapy for breast, cervical, colorectal, head and neck and prostate cancer, and to compare the economic evaluation methods applied with those defined in the guidelines used by the NICE technology appraisal programme.

METHODS

A systematic search of seven databases (MEDLINE, EMBASE, CDSR, NHSEED, HTA, DARE, EconLit) as well as research registers, the NICE website and conference proceedings was conducted in July 2012. Only economic evaluations of radiotherapy interventions in individuals diagnosed with cancer that included quality-adjusted life-years (QALYs) or life-years (LYs) were included. Included studies were appraised on the basis of satisfying essential, preferred and UK-specific methods requirements, building on the NICE Reference Case for economic evaluations and on other methods guidelines.

RESULTS

A total of 29 studies satisfied the inclusion criteria (breast 14, colorectal 2, prostate 10, cervical 0, head and neck 3). Only two studies were conducted in the UK (13 in the USA). Among essential methods criteria, the main issue was that only three (10%) of the studies used clinical-effectiveness estimates identified through systematic review of the literature. Similarly, only eight (28%) studies sourced health-related quality-of-life data directly from patients with the condition of interest. Other essential criteria (e.g. clear description of comparators, patient group indication and appropriate time horizon) were generally fulfilled, while most of the UK-specific requirements were not met.

CONCLUSION

Based on this review there is a dearth of up-to-date, robust evidence on the cost effectiveness of radiotherapy in cancer suitable to support decision making in the UK. Studies selected did not fully satisfy essential method standards currently recommended by NICE.

Accelerated chemotherapy in the treatment of urothelial cancer

To evaluate an alternative treatment for advanced or metastatic urothelial cancers, a dose-intensive combination chemotherapy regimen using carboplatin, methotrexate, vincristine and cisplatin was given to 60 patients over a 3-year period (1990 to 1993). There were 26 patients with locally advanced disease and 34 with metastatic disease; 49 patients were evaluable for response. A complete response was noted in four patients (8%) and a partial response in 15 (31%), for an overall response rate of 39%. The median survival was 12 months. Two- and 5-year survival rates were 25.5% (95% confidence interval CI) 15.2-37.0) and 7.3% (95% CI 2.2-16.4) respectively. Failure-free survival was 15.3% (95% CI 7.5-25.6) at 2 years and 5.9% (95% CI 1.6-14.4) at 5 years, with a median of 8 months. For the responders, the median duration of response was 14 months, with a range of 2-59+ months. Toxicity included myelosuppression (28% grade 4/5 neutropenia, 19% grade 4 thrombocytopenia), peripheral neuropathy (54% grade 1 and 23% grade 2/3) and ototoxicity (21% grade 1, 19% grade 2). This schedule of dose-intensified platinum-based chemotherapy for bladder cancer resulted in significant neurotoxicity without evidence of enhanced response rates or survival. Regimens such as methotrexate, vinblastine, doxorubicin and cisplatin should remain standard. Accelerated regimens may be useful in situations were it is necessary to administer chemotherapy over a short time (e.g. as part of combined modality treatment).