PET changes management and improves prognostic stratification in patients with head and neck cancer: results of a multicenter prospective study

Impact Of PET/CT On Treatment In Patients With Head And Neck Squamous Cell Carcinoma

<b><br>Introduction:</b> Although PET/CT is effective for staging HNSCC, its impact on patient management is somewhat controversial. For this reason, we considered it necessary to carry out a study in order to verify whether PET/CT helps to improve the prognosis and treatment in patients. This study was designed to address the impact of PET-FDG imaging when used alongside CT in the staging and therapeutic management of patients with HNSCC.</br> <b><br>Material and methods:</b> Data was collected from 169 patients diagnosed with HNSCC with both CT and PET/CT (performed within a maximum of 30 days of each other). It was evaluated whether discrepancies in the diagnosis of the two imaging tests had impacted the treatment.</br> <b><br>Results:</b> The combined use of CT and PET/CT led to a change in the treatment of 67 patients, who represented 39.7% of the sample. In 27.2% of cases, it entailed a change in the type of treatment which the patient received. In 3.0% of the cases, using both diagnostic tests led to modifications of the therapeutic intention of our patients.</br> <b><br>Conclusions:</b> Using PET/CT in addition to the conventional imaging method in staging resulted in more successful staging and more appropriate therapeutic decision-making.</br>.

18-Fluoride fluorodeoxyglucose positron emission tomography is impactful in newly diagnosed pancreatic adenocarcinoma

BACKGROUND

Adenocarcinoma of the pancreas has a dismal prognosis. Surgical resection increases survival but is reliant on accurate detection and staging of disease. In overseas studies, ¹⁸ F-FDG positron emission tomography (PET) has been shown to have high diagnostic accuracy and staging utility, but local data remain sparse, in part because the technique has hitherto been unfunded via the Medicare benefits schedule. Although Commonwealth funding for rare tumours (including of the pancreas) has been recently approved to commence in late 2022, the proposed item descriptor wording implies that PET should lead to a significant change in management. Accordingly, the aims of this study are to characterize PET findings in newly diagnosed pancreatic adenocarcinoma using standard parameters, such as the SUV_max , and assess the proportion of cases in which PET altered initial management planning.

METHODS

We analysed the PET findings of these cancers (presence and degree of metabolic activity in the primary lesion, as well as within malignant nodal and metastatic lesions) and compared the pre- and post-PET management plans of the referring specialists.

RESULTS

Of 51 patients we found that (a) increasing SUV_max of the primary lesion correlated with an increase in disease stage (r-value = 0.335; P-value = 0.016), and (b) PET contributed to a significant change in management in 35% of patients.

CONCLUSION

In newly diagnosed pancreatic adenocarcinoma, parameters in PET correlate with disease stage and the overall findings contribute to a significant management change in about 35% of patients.

The impact of multimodality integrated positron emission tomography-computed tomography on improving the staging and management of head and neck malignancy: a cross- sectional study

BACKGROUND

Clinical assessment of head and neck cancers is highly challenging owing to the complexity of regional anatomy and wide range of lesions. The diagnostic evaluation includes detailed physical examination, biopsy and imaging modalities for disease extent and staging. Appropriate imaging is done to enable determination of precise tumor extent and involvement of lymph nodes, and detection of distant metastases and second primary tumors.

OBJECTIVE

To evaluate the initial staging discrepancy between conventional contrasted computed tomography (CT) and 18F-fluorodeoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) and its impact on management plans for head and neck malignancies.

DESIGN AND SETTING

Prospective cross-sectional study in two tertiary-level hospitals.

METHODS

This study included 30 patients with primary head and neck malignant tumors who underwent contrasted computed tomography and whole-body 18F-FDG PET/CT assessments. The staging and treatment plans were compared with the incremental information obtained after 18F-FDG PET/CT.

RESULTS

18F-FDG PET/CT was found to raise the stage in 33.3% of the cases and the treatment intent was altered in 43.3% of them, while there was no management change in the remaining 56.7%. 18F-FDG PET/CT had higher sensitivity (96% versus 89.2%) and accuracy (93% versus 86.7%) than conventional contrast-enhanced computed tomography.

CONCLUSION

Our study demonstrated that 18F-FDG PET/CT had higher sensitivity and accuracy for detecting head and neck malignancy, in comparison with conventional contrast-enhanced computed tomography. 18F-FDG PET/CT improved the initial staging and substantially impacted the management strategy for head and neck malignancies.

Impact of pretreatment second look 18FDG-PET/CT on stage and treatment changes in head and neck cancer

•

The potential value of a second look PET/CT prior to radiotherapy was investigated.

•

New lymph node metastases were discovered in half of the patients.

•

Progression of the primary tumor and distant metastases were also observed.

•

This strategy led to changes in treatment planning in more than half of the cases.

Background

Patients diagnosed with locoregionally advanced head and neck squamous cell carcinoma (LAHNSCC) regularly undergo staging with ¹⁸F-FDG PET/CT in our center. In cases of delays in radiotherapy (RT) planning CT more than 4 weeks after initial PET/CT or clinically suspected progress, PET/CT is repeated for restaging and as an RT planning reference. Our aim was to determine the impact of second-look PET/CT on stage migration, treatment change and RT planning.

Methods

Consequent treatment changes were categorized as minor and major. Minor changes were defined as PET/CT-based modifications of RT plans, e.g., the addition of anatomical compartments, changes in high- and low-risk dose levels or both. Major changes included changes from curative to palliative treatment intent and alterations of interdisciplinary treatment plans, such as the addition of induction chemotherapy, switch to primary surgery, no treatment and/or the necessity of additional diagnostic work-up resulting in the postponement or cancellation of treatment.

Results

Thirty-two newly diagnosed LAHNSCC patients who were treated between 2014 and 2018 underwent second-look PET/CT (median interval 42.5 days). Second-look PET/CT led to locoregional and distant upstaging in 3/32 and 1/32 patients, respectively. In 1/32 patients (3%), second-look PET/CT led to a palliative approach with systemic treatment. New lymph node metastases were discovered in 16 patients, 6 of whom also showed significant progression of the primary tumor, resulting in minor changes in 16 of the remaining 31 patients (52%) who were treated curatively.

Conclusion

If RT treatment planning of LAHNSCC was delayed by more than 4 weeks after initial PET/CT staging or when progression was clinically suspected, a second look at ¹⁸FDG-PET/CT was performed. This led to changes in treatment planning in more than half of the cases, which is expected to directly influence oncologic outcomes.

Benefit of [18F]-FDG PET/CT for treatment-naïve nasopharyngeal carcinoma

Background

To test the advantages of positron emission tomography and computed tomography (PET/CT) for diagnosing lymph nodes and staging nasopharyngeal carcinoma and to investigate its benefits for survival and treatment decisions.

Methods

The performance of PET/CT and magnetic resonance imaging (MRI) in diagnosis was compared based on 460 biopsied lymph nodes. Using the propensity matching method, survival differences of T3N1M0 patients with (n = 1093) and without (n = 1377) PET/CT were compared in diverse manners. A radiologic score model was developed and tested in a subset of T3N1M0 patients.

Results

PET/CT performed better than MRI with higher sensitivity, accuracy, and area under the receiver operating characteristic curve (96.7% vs. 88.5%, p < 0.001; 88.0% vs. 81.1%, p < 0.001; 0.863 vs. 0.796, p < 0.05) in diagnosing lymph nodes. Accordingly, MRI-staged T3N0-3M0 patients showed nondifferent survival rates, as they were the same T3N1M0 if staged by PET/CT. In addition, patients staged by PET/CT and MRI showed higher survival rates than those staged by MRI alone (p < 0.05), regardless of the Epstein-Barr virus DNA load. Interestingly, SUVmax-N, nodal necrosis, and extranodal extension were highly predictive of survival. The radiologic score model based on these factors performed well in risk stratification with a C-index of 0.72. Finally, induction chemotherapy showed an added benefit (p = 0.006) for the high-risk patients selected by the model but not for those without risk stratification (p = 0.78).

Conclusion

PET/CT showed advantages in staging nasopharyngeal carcinoma due to a more accurate diagnosis of lymph nodes and this contributed to a survival benefit. PET/CT combined with MRI provided prognostic factors that could identify high-risk patients and guide individualized treatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-021-05540-8.

PET/CT Variants and Pitfalls in Head and Neck Cancers Including Thyroid Cancer

PET/CT imaging is a dual-modality diagnostic technology that merges metabolic and structural imaging. There are several currently available radiotracers, but ¹⁸F-FDG is the most commonly utilized due to its widespread availability. ¹⁸F-FDG PET/CT is a cornerstone of head and neck squamous cell carcinoma imaging. ⁶⁸Ga-DOTA-TOC is another widely used radiotracer. It allows for whole-body imaging of cellular somatostatin receptors, commonly expressed by neuroendocrine tumors and is the standard of reference for the characterization and staging of neuroendocrine tumors. The normal biodistribution of these PET radiotracers as well as the technical aspects of image acquisition and inadequate patient preparation affect the quality of PET/CT imaging. In addition, normal variants, artifacts and incidental findings may impede accurate image interpretation and can potentially lead to misdiagnosis. In order to correctly interpret PET/CT imaging, it is necessary to have a comprehensive knowledge of the normal anatomy of the head and neck and to be cognizant of potential imaging pitfalls. The interpreter must be familiar with benign conditions which may accumulate radiotracer potentially mimicking neoplastic processes and also be aware of malignancies which can demonstrate low radiotracer uptake. Appropriate use of structural imaging with either CT, MR or ultrasound can serve a complimentary role in several head and neck pathologies including local tumor staging, detection of bone marrow involvement or perineural spread, and classification of thyroid nodules. It is important to be aware of the role of these complementary modalities to maximize diagnostic accuracy and patient outcomes. The purpose of this article is to outline the basic principles of PET/CT imaging, with a focus on ¹⁸F-FDG PET/CT and ⁶⁸Ga-DOTA PET/CT. Basic physiology, variant imaging appearances and potential pitfalls of image interpretation are presented within the context of common use cases of PET technology in patients with head and neck cancers and other pathologies, benign and malignant.

PET/CT in Surgical Planning for Head and Neck Cancer

Fluorine-18 (¹⁸F)-fluorodeoxyglucose (FDG) positron emission tomography fused with computed tomography (PET/CT) is a valuable tool in surgical planning for head and neck squamous cell carcinoma (HNSCC). If performed prior to biopsy or other surgical intervention, FDG-PET/CT has high sensitivity for the detection of the primary site in patients with cervical lymph node metastases from unknown primary origin and can be used to direct the surgical workup. FDG-PET/CT is superior to CT alone for detection of nodal metastases outside the expected pattern or distant metastases or second primary cancers and can greatly affect determination of appropriate management including surgical eligibility. Prior to the advent of PET/CT, many patients undergoing (chemo)radiation-based therapy had planned post-treatment neck dissection; FDG-PET/CT now has a proven role in the evaluation of recurrent or persistent disease amenable to salvage surgery and enables safe avoidance of planned postradiation neck dissection with a high negative predictive value. Specifically for this important application, two standardized reporting metrics may be used in the head and neck anatomic region: the "Hopkins criteria" and the "Neck Imaging Reporting and Data System"; both systems produce a formalized evaluation and recommendation based on PET/CT findings. The role of PET/CT as a replacement for elective neck dissection or examination under anesthesia remains controversial but deserves further study. FDG-PET/CT has a wide-ranging impact on the surgical management of patients with HNSCC and should be used routinely in patients with unknown primary nodal disease and those presenting with advanced-stage cancers at initial staging and to assess treatment response.

Integration of 18-FDG PET/CT in the Initial Work-Up to Stage Head and Neck Cancer: Prognostic Significance and Impact on Therapeutic Decision Making

Background: The objective of this study was to assess the therapeutic and prognostic impact of integrating18F-fluorodeoxyglucose (18-FDG) positron emission tomography (PET)/computed tomography (CT) into work-up (WU) at initial staging of patients with head and neck squamous cell carcinoma (HNSCC).

Method: 477 consecutive patients (414M/63F, mean age 62.3 ± 9.7 years) with newly diagnosed HNSCC who underwent pre-treatment 18-FDG PET/CT were retrospectively included. The 18-FDG PET/CT stage (sPET) was compared to the conventional work-up stage (sCWU). A group of cancer specialists determined whether integrating PET/CT into WU at initial staging had an impact on the therapeutic decision, classifying the clinical impact as high (change in therapeutic modality), medium (change in the radiotherapy or surgical procedure), or low (modification of TNM staging and/or detection of synchronous cancer without high or medium impact). Three-year overall survival (OS) was considered as primary endpoint of the prognostic analysis.

Results: 18-FDG PET/CT had a clinical impact in 221 patients (46.3%) with a medium or high impact on management in 94 (19.5%) patients. Medium and high impact of 18-FDG PET/CT was statistically equivalent between sCWU-stage I/II and III/IV subgroups (p = 0.02). 42 patients were PET/CT-upstaged from early stage I/II to advanced stage III/IV and had a significantly lower 3-year OS than those with concordant CWU and 18-FDG PET/CT early stage (54.8 vs. 82.6%, p = 0.001).

Conclusion: This study demonstrated that implementing 18-FDG PET/CT in the initial WU of HNSCC provides valuable staging information with a better prognostic stratification. Patient management was modified for any disease stage, even for early stage I-II, with consequences on survival.

Correlation between PET/CT and CT in the staging prior to the treatment of head and neck squamous cell carcinoma

Introduction

Head and neck squamous cell carcinoma is the seventh most common malignant tumor. The advances in treatment have improved the global survival rates in the past years, although the prognosis is still grave.

Objective

The aim of the present study is to evaluate the correlation between positron emission computed tomography and computed tomography at the time of staging a previously untreated head and neck squamous cell carcinoma, and to determine which of the two imaging techniques gives us more information at the time of initial diagnosis.

Methods

Data from all patients diagnosed in our hospital of head and neck squamous cell carcinoma by a biopsy of any location or unknown primary tumor was collected, between January 2012 and July 2017. In all cases, computed tomography and positron emission computed tomography were performed with a maximum of 30 days difference between them and patients had not received any prior treatment to staging. The stage given to each case was compared based solely on the physical examination, only on the computed tomography/positron emission computed tomography, with respect to the stage given by the tumor board, observing the concordance obtained through Cramer's V statistical test.

Results

We performed a comparative analysis obtaining a correlation of 0.729 between the stage given by the tumor board and the one assigned based on the physical examination without imaging techniques. When only using computed tomography as an imaging method, the correlation was 0.848, whereas with only the use of positron emission computed tomography it was estimated at 0.957. When comparing the statistical association between staging using exclusively one of the two imaging techniques, correlation was 0.855.

Conclusion

Positron emission computed tomography is useful for the diagnosis of head and neck squamous cell carcinoma, improving the patient's staging especially when detecting cervical and distant metastases. Therefore, we consider that the use of positron emission computed tomography for the staging of patients with head and neck squamous cell carcinoma is a diagnostic test to be considered.

Workup of Suspected Chest Metastases on 18F-FDG-PET/CT in Head and Neck Cancer: Worth the Wait?

The objective of our study is to assess the impact of equivocal or positive positron emission tomography combined with low-dose noncontrast computed tomography (PET/CT) findings in the chest on treatment for head and neck cancer (HNC). We reviewed charts of patients presented at Augusta University's Head and Neck Tumor Board (AUTB) between 2013 and 2016 with the following exclusion criteria: <18 years, Veterans Affairs patients, those with incomplete data, and those without a history of head and neck squamous cell carcinoma. The lung/thorax sections of the radiologists' PET/CT reports were graded as "Positive, Equivocal, or Negative" for chest metastases. Patients who underwent workup for suspected chest metastases were assessed for treatment delays, changes in treatment plans, and complications. In addition, we evaluated the time between AUTB presentation and peri-treatment PET/CT to primary treatment initiation were calculated between groups. There was a total of 363 patients with PET/CT prior to treatment, the read was "Negative" in 71.3% (n = 259), "Equivocal" in 20.9% (n = 76), and "Positive" in 5.8% (n = 21). Of 272 patients with complete treatment data, 22 underwent workup for suspected chest metastases. Mean time from PET/CT to treatment initiation was 27.5 days without workup and 64.9 days with workup ( P < .0001), and from AUTB presentation was 29.1 days without workup and 62.5 days with workup ( P < .0001). Five (19.2%) patients experienced a complication from workup. Twenty (76.9%) patients had no changes in their treatment plan after workup. In conclusion, our results for potential chest metastases on PET/CT in patients with HNC are often not clear-cut. Workup of suspected chest metastasis based on PET/CT findings significantly delays primary treatment initiation and may cause serious complications.

Molecular Imaging Using PET/CT for Radiation Therapy Planning for Adult Cancers: Current Status and Expanding Applications

Accurate tumor delineation is a priority in radiation therapy (RT). Metabolic imaging has a key and evolving role in target volume selection and delineation. This is especially so for non-small cell lung cancer, squamous cell cancer of the head and neck, and lymphoma, for which positron emission tomography/computed tomography (PET/CT) is complimentary to structural imaging modalities, not only in delineating primary tumors, but also often in revealing previously undiagnosed regional nodal disease. At some sites, PET/CT has been confirmed to enable target size reduction compared with structural imaging alone, with enhanced normal tissue sparing and potentially allowing for dose escalation. These contributions often dramatically affect RT strategies. However, some limitations exist to the use of fluorodeoxyglucose-PET in RT planning, including its relatively poor spatial resolution and partial voluming effects for small tumors. A role is developing for contributions from metabolic imaging to RT planning at other tumor sites and exciting new applications for the use of non-fluorodeoxyglucose metabolic markers for RT planning.

Intended Versus Inferred Treatment After 18F-Fluoride PET Performed for Evaluation of Osseous Metastatic Disease in the National Oncologic PET Registry

We have previously reported that PET with ¹⁸F-fluoride (NaF PET) for assessment of osseous metastatic disease led to changes in intended management in a substantial fraction of patients with prostate or other types of cancer participating in the National Oncologic PET Registry. This study was performed to assess the concordance of intended patient management after NaF PET and inferred management based on analysis of Medicare claims. Methods: We analyzed linked post-NaF PET data of consenting National Oncologic PET Registry participants age 65 y or older from 2011 to 2014 and their corresponding Medicare claims. Post-NaF PET treatment plans, including combinations of 2 modes of therapy, were assessed for their concordance with clinical actions inferred from Medicare claims. NaF PET studies were stratified by indication (initial staging [IS] or suspected first osseous metastasis [FOM]) and cancer type (prostate, lung, or other cancers). Agreement was assessed between post-NaF PET intended management plans for treatment (surgery, radiotherapy, or systemic therapy) within 90 d for lung and 180 d for prostate or other cancers, and for watching (the absence of treatment claims for ≥60 d) as compared with claims-inferred care. Results: Actions after 9,898 scans were assessed. After NaF PET for IS, there was claims agreement for planned surgery in 76.0% (19/25) lung, 75.4% (98/130) other cancers, and 58.9% (298/506) prostate cancer. Claims confirmed chemotherapy plans after NaF PET done for IS or FOM in 81.0% and 73.5% for lung cancer (n = 148 and 136) and 69.4% and 67.5% for other cancers (n = 111 and 228). For radiotherapy plans, agreement ranged from 80.0% to 84.4% after IS and 68.4% to 74.0% for suspected FOM. Concordance was greatest for androgen deprivation therapy (ADT) (86.0%, n = 308) alone or combined with radiotherapy in prostate cancer IS (80.8%, n = 517). In prostate FOM, the concordance across all treatment plans was lower if the patients had ADT claims within 180 d before NaF PET. Agreement with nontreatment plans was high for FOM (87.2% in other cancers and 78.6% if no prior ADT in prostate) and low after IS (40.7%-62.5%). Conclusion: Concordance of post-NaF PET plans and claims was substantial and higher overall for IS than for FOM.

Up-front PET/CT changes treatment intent in patients with head and neck squamous cell carcinoma

PURPOSE

In patients with newly diagnosed head and neck squamous cell carcinoma (HNSCC), we wanted to examine the differences in overall treatment decisions, i.e. curative versus palliative treatment intent, reached by a multidisciplinary team conference (MDTC) based on 18F-fluoro-deoxy-glucose-positron emission tomography/computed tomography (PET/CT) or chest X-ray + MRI of the head and neck (CXR/MRI).

PATIENTS AND METHODS

This was a prospective blinded cohort study based on paired data. Consecutive patients with histologically verified primary HNSCC were invited to participate. All included patients underwent CXR/MRI and PET/CT before diagnostic biopsy. An ordinary MDTC using all available imaging was conducted as per standard practice. After at least 3 months (to eliminate recall bias in the team), the first project MDTC was conducted, based on either CXR/MRI or PET/CT, and the tumor board drew conclusions regarding treatment. After an additional 3 months, a second project MDTC was conducted using the complementary imaging modality.

RESULTS

A total of 307 patients were included. Based on CXR/MRI, 303 patients (99%) were recommended for curative treatment and only four patients (1%) for palliative treatment. Based on PET/CT, the MDTC concluded that 278 (91%) patients were suitable for curative treatment and 29 (9%) patients for palliative treatment. The absolute difference of 8% was statistically significant (95% CI: 4.8%-11.5%, p < 0.001).

CONCLUSIONS

A PET/CT-based imaging strategy significantly changed the decisions regarding treatment intent made by a MDTC for patients diagnosed with HNSCC, when compared with the standard imaging strategy of CXR/MRI.

A PET/CT-Based Strategy Is a Stronger Predictor of Survival Than a Standard Imaging Strategy in Patients with Head and Neck Squamous Cell Carcinoma

Our purpose was to examine whether staging of head and neck squamous cell carcinoma (HNSCC) by upfront ¹⁸F-FDG PET/CT (i.e., on the day of biopsy and before the biopsy) discriminates survival better than the traditional imaging strategies based on chest x-ray plus head and neck MRI (CXR/MRI) or chest CT plus head and neck MRI (CCT/MRI). Methods: We performed a masked prospective cohort study based on paired data. Consecutive patients with histologically verified primary HNSCC were recruited from Odense University Hospital from September 2013 to March 2016. All patients underwent CXR/MRI, CCT/MRI, and PET/CT on the same day. Tumors were categorized as localized (stages I and II), locally advanced (stages III and IVB), or metastatic (stage IVC). Discriminative ability for each imaging modality with respect to HNSCC staging were compared using Kaplan-Meier analysis, Cox proportional hazards regression with the Harrell C-index, and net reclassification improvement. Results: In total, 307 patients with histologically verified HNSCC were included. Use of PET/CT significantly altered the stratification of tumor stage when compared with either CXR/MRI or CCT/MRI (χ², P < 0.001 for both). Cancer stages based on PET/CT, but not CXR/MRI or CCT/MRI, were associated with significant differences in mortality risk on Kaplan-Meier analyses (P ≤ 0.002 for all PET/CT-based comparisons). Furthermore, overall discriminative ability was significantly greater for PET/CT (C-index, 0.712) than for CXR/MRI (C-index, 0.675; P = 0.04) or CCT/MRI (C-index, 0.657; P = 0.02). Finally, PET/CT was significantly associated with a positive net reclassification improvement when compared with CXR/MRI (0.184, P = 0.03) but not CCT/MRI (0.094%, P = 0.31). Conclusion: Tumor stages determined by PET/CT were associated with more distinct prognostic properties in terms of survival than those determined by standard imaging strategies.

Clinical Practice in PET/CT for the Management of Head and Neck Squamous Cell Cancer

OBJECTIVE

The purpose of this article is to summarize the evidence for the value of PET/CT for the management of patients with head and neck squamous cell cancer and suggest best clinical practices.

CONCLUSION

FDG PET/CT is a valuable imaging tool for identifying unknown primary tumors in patients with known cervical node metastases leading to management change and is the standard of care for the initial staging of stage III and IV head and neck squamous cell carcinomas (HNSCCs), for assessing therapy response when performed at least 12 weeks after chemoradiation therapy, and for avoiding unnecessary planned neck dissection. Neck dissection is avoided if PET/CT findings are negative-regardless of the size of the residual neck nodes-because survival outcomes are not compromised. FDG PET/CT is valuable in detecting recurrences and metastases during follow-up when suspected because of clinical symptoms and serves as a prognostic marker for patient survival outcomes, for 5 years. Using FDG PET/CT for routine surveillance of HNSCC after 6 months of treatment without any clinical suspicion should be discouraged.

[PET-CT in head and neck cancer]

The importance of ¹⁸F-fluorodesoxyglucose positron-emission tomography (FDG-PET) for the diagnosis of malignant disease is increasing. On one hand, this is due to the high sensitivity of this method, on the other, because the entire body can be examined. FDG-PET can be particularly advantageous for the diagnosis of head and neck tumors, where tumor staging is an important prognostic parameter and essentially determines the therapeutic regimen. This article presents the different possibilities for combined evaluation with PET and computed tomography (CT) for the diagnosis of patients with head and neck cancer. Special focus is placed on primary staging and tumor follow-up, as well as on the role of PET-CT in the diagnosis of patients with cancer of unknown primary origin (CUP). The use of PET-CT for radiotherapy planning and new aspects of PET technology are also discussed.

Role of Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography in the Evaluation of Head and Neck Carcinoma

Fluorodeoxyglucose (FDG)-positron emission tomography-computed tomography (PET-CT) has been playing a pivotal role in tumor imaging for the past 20 years. Head and neck (HN) cancers are a good example that can illustrate such unique role of FDG imaging contributing to the patient's management. In this review article, we will describe the normal physiological distribution of FDG within HN structures focusing on its limitations and pitfalls. In addition, we will be also describing its role in the initial staging and restaging of the disease, particularly with regard to therapy response assessment. Furthermore, its role in the evaluation of patients with malignant cervical adenopathy from an unknown primary will be described. In 2016, the Royal College of Radiologists in its third edition published evidence-based guidelines for PET-CT use in HN cancer emphasizing its rule in all these clinical scenarios that are being described in this review. Finally, we will be highlighting future directions in the field of molecular imaging of HN tumors with a special emphasis on the new PET tracers.

Non-18F-FDG PET/CT in the management of patients affected by HNC: state-of-the-art

PET/computed tomography with F-fluorodeoxyglucose is considered a powerful molecular imaging technique that can provide useful information in the management of patients affected by head and neck cancer. However, misleading findings have been reported because of nonspecific uptake caused by peritumoural inflammation and physiologic changes in nonmalignant tissues in the head and neck region. More specific β-emitting tracers have been introduced that can track other pathological processes. We aimed to review the existing literature performing the search until June 2015 on non-F-fluorodeoxyglucose PET tracers in head and neck cancer to highlight their role in clinical practice.

Role of fluorine-18 fluorodeoxyglucose PET/CT in head and neck oncology: the point of view of the radiation oncologist

Squamous cell carcinoma is the most common malignant tumour of the head and neck. The initial TNM staging, the evaluation of the tumour response during treatment, and the long-term surveillance are crucial moments in the approach to head and neck squamous cell carcinoma (HNSCC). Thus, at each of these moments, the choice of the best diagnostic tool providing the more precise and larger information is crucial. Positron emission tomography with fluorine-18 fludeoxyglucose integrated with CT (¹⁸F-FDG-PET/CT) rapidly gained clinical acceptance, and it has become an important imaging tool in routine clinical oncology. However, controversial data are currently available, for example, on the role of ¹⁸F-FDG-PET/CT imaging during radiotherapy planning, the prognostic value or its real clinical impact on treatment decisions. In this article, the role of ¹⁸F-FDG-PET/CT imaging in HNSCC during pre-treatment staging, radiotherapy planning, treatment response assessment, prognosis and follow-up is reviewed focusing on current evidence and controversial issues. A proposal on how to integrate ¹⁸F-FDG-PET/CT in daily clinical practice is also described.

The role of PET/CT in the management of patients affected by head and neck tumors: a review of the literature

The management of head and neck tumor (HNSCC) has been changing over the years, especially due to the aid of imaging techniques that help physicians to attain a correct diagnosis. These techniques represent a valuable tool to help tailor treatment and during follow-up of patients affected by malignancies. The aim of this review is to summarize the results of the most recent and relevant studies about the use of PET imaging in HNSCCs. This review is divided into six chapters: (1) The role of PET/CT in the pre-treatment phase; (2) PET/CT and radiotherapy planning; (3) PET/CT in the post-treatment setting; (4) PET/CT and SUVmax for prediction of prognosis; (5) miscellanea on the utility of PET in specific HNSCCs; (6) non-FDG PET tracers used in HNSCC. Promising results have been obtained so far. Despite the encouraging outcomes, more investigations are needed to warrant the value of this technique, especially in the pre-treatment setting.

Prognostic utility of (18)F-FDG PET-CT performed prior to and during primary radiotherapy for nasopharyngeal carcinoma: Index node is a useful prognostic imaging biomarker site

PURPOSE

To evaluate the prognostic value of (18)F-FDG-PET-CT performed prior to (prePET) and during the third week (iPET) of radiation therapy (RT) in nasopharyngeal carcinoma (NPC).

MATERIALS AND METHODS

Thirty-patients with newly diagnosed loco-regionally advanced NPC treated with radical RT underwent prePET and iPET. The median follow-up was 26months (8-66.9). The maximum-standardised-uptake-value (SUVmax), metabolic-tumour-volume (MTV) and total-lesional-glycolysis (TLG) of the primary tumour (PT), index-node (IN) (lymph node with highest TLG), total-lymph-nodes (TN) and combined primary-tumour and nodal (PTN), and their % reductions in iPET were analysed, and results were correlated with 2-year Kaplan-Meier loco-recurrence-free-survival (LRFS), regional-failure-free-survival (RFFS), distant-metastatic-failure-free-survival (DMFFS), disease-free-survival (DFS), and overall-survival (OS). Optimal-cutoffs (OC) were derived from Receiver-Operating-Characteristic curves.

RESULTS

For LRFS, the only predictor was reduction in PT MTV by >50%: 95.2% vs. 75.0%, p=0.024. For other treatment outcomes, only nodal or PTN predicted outcomes. The IN SUVmax (pre-PET-OC=10.45g/mL and iPET-OC=8.15) and TLG (prePET-OC=90g and iPET-OC=33.4) were the best predictors of outcome: RFFS (iPET SUVmax/TLG): 100% vs. 50%, p<0.001 and 100% vs. 44%, p=0.032; DMFFS (prePET SUVmax/TLG); 100% vs. 51.9%, p=0.004 and 100% vs. 47.6%, p=0.002; DFS (prePET TLG and iPET SUVmax): 87.5% vs. 33%, p=0.045 and 78.7% vs. 20%, p=0.01; and OS (prePET TLG): 100% vs 66.3%, p=0.036.

CONCLUSIONS

We have demonstrated IN of prePET and iPET to be a feasible and potentially useful novel imaging biomarker to predict for patients with NPC who have a high risk of regional or distant metastatic failure. Future work is required to validate our findings in a well-powered, prospective study with a standardised treatment protocol, and their potential use to guide individualised therapy for NPC.

Positron-emission tomography/computed tomography imaging in head and neck oncology: An update

Cancers of the head and neck account for more than half a million cases worldwide annually, with a significant majority diagnosed as squamous cell carcinoma (HNSCC). Imaging studies such as contrast-enhanced computed tomography (CT), magnetic resonance imaging (MRI) and ¹⁸F-2-fluoro-2-deoxy-D-glucose positron-emission tomography/computed tomography (¹⁸F-FDG PET/CT) are widely used to determine the presence and extent of tumors and metastatic disease, both before and after treatment. Advances in PET/CT imaging have allowed it to emerge as a superior imaging modality compared to both CT and MRI, especially in detection of carcinoma of unknown primary, cervical lymph node metastasis, distant metastasis, residual/recurrent cancer and second primary tumors, often leading to alteration in management. PET/CT biomarker may further provide an overall assessment of tumor aggressiveness with prognostic implications. As new developments emerged leading to better understanding and use of PET/CT in head and neck oncology, the aim of this article is to review the roles of PET/CT in both pre- and post-treatment management of HNSCC and PET-derived parameters as prognostic indicators.

Special Techniques in PET/Computed Tomography Imaging for Evaluation of Head and Neck Cancer

PET with fluorodeoxyglucose F 18 (FDG)/computed tomography (CT) imaging has significantly improved the management of head and neck cancer. FDG, however, is not tumor-specific and various image interpretation pitfalls may occur because of false-positive and -negative causes of FDG uptake. Routine imaging examination of head and neck malignancies does not yield all of the necessary data, even with the most advanced imaging technique. Specific interventions, such as use of different dynamic maneuvers and pharmacologic interventions, may provide useful information about the lesion. This article reviews the use of special techniques in FDG PET/CT imaging and whole-body FDG PET/CT imaging for evaluation of head and neck cancer.

Utility of PET for Radiotherapy Treatment Planning

PET imaging has contributed substantially in oncology by allowing improved clinical staging and guiding appropriate cancer management. Integration with radiotherapy planning via PET/computed tomography (CT) simulation enables improved target delineation, which is paramount for conformal radiotherapy techniques. This article reviews the present literature regarding implications of PET/CT for radiotherapy planning and management.

Early post-treatment FDG PET predicts survival after 90Y microsphere radioembolization in liver-dominant metastatic colorectal cancer

PURPOSE

The aim of this study was to evaluate the predictive value of early metabolic response 4 weeks post-treatment using (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT in patients with unresectable hepatic metastases of colorectal cancer (CRC) undergoing radioembolization (RE) with (90)Y-labelled microspheres.

METHODS

A total of 51 consecutive patients with liver-dominant metastases of CRC were treated with RE and underwent (18)F-FDG PET/CT at baseline and 4 weeks after RE. In each patient, three hepatic metastases with the highest maximum standardized uptake value (SUVmax) were selected as target lesions. Metabolic response was defined as >50 % reduction of tumour to liver ratios. Survival analyses using Kaplan-Meier and multivariate analyses were performed to identify prognostic factors for overall survival (OS). Investigated baseline characteristics included age (>60 years), performance status (Eastern Cooperative Oncology Group >1), bilirubin (>1.0 mg/dl), hepatic tumour burden (>25 %) and presence of extrahepatic disease.

RESULTS

The median OS after RE was 7 months [95 % confidence interval (CI) 5-8]; early metabolic responders (n = 33) survived longer than non-responders (p < 0.001) with a median OS of 10 months (95 % CI 3-16) versus 4 months (95 % CI 2-6). Hepatic tumour burden also had significant impact on treatment outcome (p < 0.001) with a median OS of 5 months (95 % CI, 3-7) for patients with >25 % metastatic liver replacement vs 14 months (95 % CI 6-22) for the less advanced patients. Both factors (early metabolic response and low hepatic tumour burden) remained as independent predictors of improved survival on multivariate analysis.

CONCLUSION

These are the first findings to show that molecular response assessment in CRC using (18)F-FDG PET/CT appears feasible as early as 4 weeks post-RE, allowing risk stratification and potentially facilitating early response-adapted treatment strategies.

Positron emission tomography and stage migration in head and neck cancer

IMPORTANCE

Since 2001, there has been a rapid adoption of positron emission tomography (PET) for diagnosis and American Joint Committee on Cancer (AJCC) staging of head and neck cancer (HNC) without data describing improved clinical outcomes.

OBJECTIVE

To determine the association between increased use of PET and stage and/or survival for patients with HNC in the managed care environment.

DESIGN, SETTING, AND PARTICIPANTS

Adult patients diagnosed as having HNC (n = 958) from 2000 to 2008 at 4 integrated health systems were identified via tumor registries linked to administrative data. The AJCC stage distribution, patient and treatment characteristics, and survival between pre-PET era (2000-2004) vs PET era (2005-2008) and use of PET vs no use of PET during the PET era were compared. The AJCC stages were categorized to represent localized (stage I or II), locally advanced (stage III, IVA, or IVB), and metastatic (stage IVC) disease.

INTERVENTIONS

Treatments were determined by billing codes for surgery, radiation treatment, and chemotherapy.

MAIN OUTCOMES AND MEASURES

The primary outcome for this study was the use of PET. Secondary outcomes included treatment received and 2-year survival. A logit model estimated the effects of PET on diagnosis of locally advanced disease. Kaplan-Meier estimates described overall survival differences between PET and non-PET. Cox regression evaluated the association of PET on survival in patients with locally advanced disease.

RESULTS

An association between PET and locally advanced disease was found (odds ratio, 2.86 [95% CI, 1.90-4.29) (P < .001). Two-year overall survival for patients with locally advanced disease with and without PET was 52% and 32%, respectively (P = .004), but there was no difference for all stages (P = .69). On Cox proportional hazard regression, PET had no association with survival in patients with locally advanced disease (hazard ratio, 1.208 [95% CI, 0.778-1.877]) (P = .40).

CONCLUSIONS AND RELEVANCE

The increasing use of PET among patients with HNC is associated with a greater number of patients with higher-stage disease and a dilution of the population with higher-stage disease with patients who have a better prognosis. Thus, the improved survival in patients with locally advanced disease likely reflects selection bias and stage migration. Further research on PET use among patients with HNC is necessary to determine if it results in improved treatment for individual patients.

Impact of initial FDG PET/CT in the management plan of patients with locally advanced head and neck cancer

OBJECTIVE

To determine the impact of initial FDG PET/CT staging on clinical stage and the management plan in patients with locally advanced head and neck cancer (LAHNC).

MATERIALS AND METHODS

We retrospectively reviewed the records of 72 consecutive patients (2007-2010) staged with PET/CT and conventional CT with tumours of hypopharynx/larynx (26 patients, 36 %), oral cavity (17 patients, 24 %), oropharynx (16 patients, 22 %), nasopharynx (12 patients, 17 %), and others (2 %). The impact of PET/CT on management plans was considered high when PET/CT changed the planned treatment modality or treatment intent, and intramodality changes were considered as minor changes with low impact.

RESULTS

FDG PET/CT changed the stage in 27 patients and had high impact on the management plan in 12 % of patients (detection of distant metastases in 6 patients and stage II in 2 patients). Intramodality changes were more frequent: FDG PET/CT altered the TNM stage in 18/72 (25 %) of patients, upstaging N stage in 90 % of patients with low impact.

CONCLUSIONS

Initial FDG PET/CT staging not only improves stage but also affects the management plan in LAHNC patients.

Role of 18F-FDG PET/CT in pre and post treatment evaluation in head and neck carcinoma

Head and neck cancer (HNC) ranks as the 6^th most common cancer worldwide, with the vast majority being head and neck squamous cell carcinoma (HNSCC). The majority of patients present with complicated locally advanced disease (typically stage III and IV) requiring multidisciplinary treatment plans with combinations of surgery, radiation therapy and chemotherapy. Tumor staging is critical to decide therapeutic planning. Multiple challenges include accurate tumor localization with precise delineation of tumor volume, cervical lymph node staging, detection of distant metastasis as well as ruling out synchronous second primary tumors. Some patients present with cervical lymph node metastasis without obvious primary tumors on clinical examination or conventional cross sectional imaging. Treatment planning includes surgery, radiation, chemotherapy or combinations that could significantly alter the anatomy and physiology of this complex head and neck region, making assessment of treatment response and detection of residual/ recurrent tumor very difficult by clinical evaluation and computed tomography (CT) or magnetic resonance imaging (MRI). ¹⁸F-2-fluoro-2-deoxy-D-glucose positron emission tomography/CT (¹⁸F-FDG PET/CT) has been widely used to assess HNC for more than a decade with high diagnostic accuracy especially in detection of initial distant metastasis and evaluation of treatment response. There are some limitations that are unique to PET/CT including artifacts, lower soft tissue contrast and resolution as compared to MRI, false positivity in post-treatment phase due to inflammation and granulation tissues, etc. The aim of this article is to review the roles of PET/CT in both pre and post treatment management of HNSCC including its limitations that radiologists must know. Accurate PET/CT interpretation is the crucial initial step that leads to appropriate tumor staging and treatment planning.

Feasibility and incremental benefit of puffed-cheek 18F-FDG PET/CT on oral cancer patients

PURPOSE

The complexity of small oral cavity and intimate apposition of the oral cavity mucosal surfaces make CT identification of obvious masses difficult. Puffed-cheek CT improves the evaluation of oral cavity lesions. We used the puffed-cheek maneuver with 18F-FDG PET/CT scans to determine the feasibility and accuracy in clinical practice and to identify any benefits.

PATIENTS AND METHODS

Twenty-two patients with oral cancer were included. They were instructed to perform the puffed-cheek maneuver after a conventional 18F-FDG PET/CT scan. Two physicians reviewed the puffed-cheek and conventional 18F-FDG PET/CT images and achieved consensus about the cancer extent, location, and dental artifacts before classifying and grading the oral cancers. Dichotomous results of localized or extended cancer and artifact grading scores from the puffed-cheek and conventional 18F-FDG PET/CT methods were compared using McNemar test and the Wilcoxon signed-rank test. P < 0.05 was considered significant.

RESULTS

The puffed-cheek maneuver with 18F-FDG PET/CT was practical and had incremental benefits. The conventional 18F-FDG PET/CT classified 12 patients correctly as having localized or extended cancer, and the puffed-cheek 18F-FDG PET/CT classified 21 patients correctly. Puffed-cheek 18F-FDG PET/CT found a synchronous skip cancer and provided detailed cancer delineation. This method might reduce the effects of dental artifacts without undesirable muscular FDG uptake.

CONCLUSIONS

Puffed-cheek PET/CT is feasible in the current clinical setting and can improve the delineation of oral cancer extent and location, with a potential benefit of reducing dental artifacts.

Intended versus inferred care after PET performed for initial staging in the National Oncologic PET Registry

The National Oncologic PET Registry (NOPR) collected data on intended management before and after PET in cancer patients. We have previously reported that PET was associated with a change in intended management of about one third of patients and was consistent across cancer types. It is uncertain if intended management plans reflect the actual care these patients received. One approach to assess actual care received is using administrative claims to categorize the type and timing of clinical services.

METHODS

NOPR data from 2006 to 2008 were linked to Medicare claims for consenting patients aged 65 y or older undergoing initial-staging PET scanning for bladder, ovarian, pancreatic, small cell lung, or stomach cancers. We determined the 60-d agreement between claims-inferred care and NOPR treatment plans.

RESULTS

Patients (n = 4,661) were assessed, and 30%-52% had metastatic disease. Planned treatments were about two-thirds monotherapy, of which 46% was systemic therapy only, and one-third combinations. Claims paid by 60 d confirmed the NOPR plan of any systemic therapy, radiotherapy, or surgery in 79.3%, 64.7%, and 63.6%, respectively. Single-mode plans were much more often confirmed: systemic therapy in more than 85% of patients with ovarian, pancreatic, and small cell lung cancers and surgery in more than 73% of those with bladder, pancreatic, and stomach cancers. Intended combination treatments had claims for both in only 28% of patients receiving surgery-based combinations and in 55% receiving chemoradiotherapy. About 90% of patients with NOPR-planned systemic therapy had evaluation or management claims from a medical oncologist. An age of less than 75 y was associated more often with confirmation of chemotherapy, less often for radiotherapy but not with confirmation of surgery. Performance status or comorbidity did not explain confirmation rates within action categories, but confirmation rates were higher if the referrer specialized in the planned treatment.

CONCLUSION

Claims confirmations of NOPR intent for initial staging were widely variable but were higher than previously reported for restaging PET, suggesting that measuring change in intended management is a reasonable method for assessing the impact diagnostic tests have on actual care.

Functional imaging in radiation therapy planning for head and neck cancer

Functional imaging and its application to radiotherapy (RT) is a rapidly expanding field with new modalities and techniques constantly developing and evolving. As technologies improve, it will be important to pay attention to their implementation. This review describes the main achievements in the field of head and neck cancer (HNC) with particular remarks on the unsolved problems.

Intended versus inferred management after PET for cancer restaging: analysis of Medicare claims linked to a coverage with evidence development registry

BACKGROUND

The National Oncologic PET Registry (NOPR) ascertained changes in the intended management of cancer patients using questionnaire data obtained before and after positron emission tomography (PET) under Medicare's coverage with evidence development policy.

OBJECTIVE

To assess the concordance between intended care plans and care received as ascertained through administrative claims data.

RESEARCH DESIGN

Analysis of linked data of NOPR participants from 2006 to 2008 and their corresponding Medicare claims.

SUBJECTS

Consenting patients aged older than 65 years having their first PET for restaging of bladder, kidney, ovarian, pancreas, prostate, small cell lung, or stomach cancer.

MEASURES

: Agreement (positive predictive values and κ) between NOPR post-PET intended management plans for treatment (systemic therapy, radiotherapy, surgery, or combinations), biopsy, or watching as compared to claims-inferred care 30 days after PET.

RESULTS

A total of 8460 patients with linked data were assessed. A total of 43.5% had metastatic disease and 45.3% had treatment planned (predominantly systemic therapy only), 11.1% biopsy and 43.5% watching. Claims-confirmed intended plans (positive predictive value) for single-mode systemic therapy in 62.0%, radiation in 66.0%, surgery in 45.6%, and biopsy in 55.7%. A total of 25.7% of patients with a plan of watching had treatment claims. By cancer type, κ ranged for systemic therapy only from 0.17 to 0.40 and for watching from 0.21 to 0.41. Agreement rates varied by cancer types but were minimally associated with patient age, performance status, comorbidity, or stage.

CONCLUSIONS

Among elderly cancer patients undergoing PET for restaging, there was moderate concordance between their physicians' planned management and claims-inferred actions within a narrow time window. When higher accuracy levels are required in future coverage with evidence development studies, alternative designs will be needed.

Should positron emission tomography/computed tomography be the first rather than the last test performed in the assessment of cancer?

Cancer is a major cause of illness and death in Western society and is associated with a heavy concomitant economic burden. Although use of imaging comprises only a small proportion of the fiscal impact of cancer, its use has been increasing over recent decades, causing concern amongst funders of health care and efforts to constrain the use of new imaging tests with a relatively high unit cost. In clinical practice, positron emission tomography/computed tomography (PET/CT) is generally performed when less expensive tests have left some uncertainty regarding appropriate management. In this setting, its utility relates to provision of incremental diagnostic information. However, given that superior diagnostic information can positively affect patient management, wherein the majority of costs reside, it may be both more efficient and cost effective to go directly to the most accurate investigation in certain situations. For PET/CT, the ability to provide more accurate assessment of metastatic status than is available from conventional diagnostic paradigms provides a rationale for its independent rather than incremental use in patients presenting with either a high likelihood of malignancy or proven malignancy of a locally advanced nature and an accordingly high risk of metastatic disease. A randomized trial design is described that could be used to test this hypothesis.

Improving target definition for head and neck radiotherapy: a place for magnetic resonance imaging and 18-fluoride fluorodeoxyglucose positron emission tomography?

Defining the target for head and neck radiotherapy is a critical issue with the introduction of steep dose gradients associated with intensity-modulated radiotherapy. Tumour delineation inaccuracies are a major source of error in radiotherapy planning. The integration of 18-fluoride fluorodeoxyglucose positron emission tomography ((18)FDG-PET) and magnetic resonance imaging directly into the radiotherapy planning process has the potential to greatly improve target identification/selection and delineation. This raises a range of new issues surrounding image co-registration, delineation methodology and the use of functional data and treatment adaptation. This overview will discuss the practical aspects of integrating (18)FDG-PET and magnetic resonance imaging into head and neck radiotherapy planning.

The Impact of (18)F-FDG PET CT Prior to Chemoradiotherapy for Stage III/IV Head and Neck Squamous Cell Carcinoma

Introduction. To determine the value of a FDG-PET-CT scan in patients with locally advanced head and neck squamous cell carcinoma (HNSCC) prior to chemoradiotherapy. Materials and Methods. Consecutive patients with stage III or IV HNSCC who had undergone a staging FDG-PET-CT scan prior to chemoradiotherapy between August 2008 and April 2011 were included. Clinical details and conventional imaging (CT and/or MRI) were, retrospectively, reviewed, a TNM stage was assigned, and levels of cervical lymph node involvement were documented. This process was repeated with the addition of FDG-PET-CT. Radiotherapy plans were reviewed for patients with an alteration identified on TNM staging and/or nodal level identification with FDG-PET-CT and potential alterations in radiotherapy planning were documented. Results. 55 patients were included in the analysis. FDG-PET-CT altered the TNM stage in 17/55 (31%) of patients, upstaging disease in 11 (20%) and downstaging in 6 (11%); distant metastases were identified by FDG-PET-CT in 1 (2%) patient. FDG-PET-CT altered the lymph node levels identified in 22 patients (40%), upclassifying disease in 16 (29%) and downclassifying in 6 (11%). Radiotherapy plans were judged retrospectively to have been altered by FDG-PET-CT in 10 patients (18%). Conclusions. The use of FDG-PET-CT potentially impacts upon both treatment decisions and radiotherapy planning.

Using patient management as a surrogate for patient health outcomes in diagnostic test evaluation

Background

Before a new test is introduced in clinical practice, evidence is needed to demonstrate that its use will lead to improvements in patient health outcomes. Studies reporting test accuracy may not be sufficient, and clinical trials of tests that measure patient health outcomes are rarely feasible. Therefore, the consequences of testing on patient management are often investigated as an intermediate step in the pathway. There is a lack of guidance on the interpretation of this evidence, and patient management studies often neglect a discussion of the limitations of measuring patient management as a surrogate for health outcomes.

Methods

We discuss the rationale for measuring patient management, describe the common study designs and provide guidance about how this evidence should be reported.

Results

Interpretation of patient management studies relies on the condition that patient management is a valid surrogate for downstream patient benefits. This condition presupposes two critical assumptions: the test improves diagnostic accuracy; and the measured changes in patient management improve patient health outcomes. The validity of this evidence depends on the certainty around these critical assumptions and the ability of the study design to minimise bias. Three common designs are test RCTs that measure patient management as a primary endpoint, diagnostic before-after studies that compare planned patient management before and after testing, and accuracy studies that are extended to report on the actual treatment or further tests received following a positive and negative test result.

Conclusions

Patient management can be measured as a surrogate outcome for test evaluation if its limitations are recognised. The potential consequences of a positive and negative test result on patient management should be pre-specified and the potential patient benefits of these management changes clearly stated. Randomised comparisons will provide higher quality evidence about differences in patient management using the new test than observational studies. Regardless of the study design used, the critical assumption that patient management is a valid surrogate for downstream patient benefits or harms must be discussed in these studies.

Linking the evidence: intermediate outcomes in medical test assessments

OBJECTIVES

The aim of this study is to review how health technology assessments (HTA) of medical tests incorporate intermediate outcomes in conclusions about the effectiveness of tests on improving health outcomes.

METHODS

Systematic review of English-language test assessments in the HTA database from January 2005 to February 2010, supplemented by a search of the Web sites of International Network of Agencies for Health Technology Assessment (INAHTA) members.

RESULTS

A total of 149 HTAs from eight countries were assessed. Half evaluated tests for screening or diagnosis, a third for disease classification (including staging, prognosis, monitoring), and a fifth for multiple purposes. In seventy-one HTAs (48 percent) only diagnostic accuracy was reported, while in seventeen (11 percent) evidence of health outcomes was reported in addition to accuracy. Intermediate outcomes, mainly the impact of test results on patient management, were considered in sixty-one HTAs (41 percent). Of these, forty-seven identified randomized trials or observational studies reporting intermediate outcomes. The validity of these intermediate outcomes as a surrogate for health outcomes was not consistently discussed; nor was the quality appraisal of this evidence. Clear conclusions about whether the test was effective were included in approximately 60 percent of HTAs.

CONCLUSIONS

Intermediate outcomes are frequently assessed in medical test HTAs, but interpretation of this evidence is inconsistently reported. We recommend that reviewers explain the rationale for using intermediate outcomes, identify the assumptions required to link intermediate outcomes and patient benefits and harms, and assess the quality of included studies.