Clinical Decisions Associated With Positron Emission Tomography in a Prospective Cohort of Patients With Suspected or Known Cancer at One United States Center

Impact of positron-emission tomography on the surgical treatment of locoregionally recurrent colorectal cancer

BACKGROUND

The effect of positron emission tomography (PET) on the surgical treatment of locoregionally recurrent colorectal cancer (LRRCRC) remains unclear and warrants further investigation.

MATERIAL AND METHODS

A total of 193 patients with LRRCRC were identified from a prospectively maintained institutional database, of whom 134 LRRCRCs were deemed resectable and underwent resection with curative intent, whereas the remaining 59 LRRCRCs were unresectable. Patients with resectable LRRCRC were further classified according to whether recurrence was detected solely by PET (n = 35, PET-only group) or by a combination of computed tomography (CT)/magnetic resonance imaging (MRI) and PET (n = 99, CT/MRI/PET group). Clinicopathologic features, operative morbidity/mortality, and overall survival were compared between the patient groups based on long-term follow-up for at least 5 years.

RESULTS

Patients in the PET-only group tended to have less extensive organ resection (p = 0.0074), less blood loss (p < 0.0001), and shorter operation time and hospitalization (p < 0.0001), but surgical complication and readmission rates were not significantly different (p > 0.05) compared with the CT/MRI/PET group. Although the PET-only group had significantly higher R0 resection rate (80 % vs. 54.55 %, p = 0.0079), they also had a higher risk (17.14 % vs. 2.02 %, p = 0.0011) of sham operation. The estimated 5-year and 10-year survival rates significantly decreased in order (p < 0.0001) from PET-only (85.71 % and 57.98 %) and CT/MRI/PET (41.41 % and 15.93 %) to unresectable group of patients (16.95 % and 1.88 %). Subset analysis of the CT/MRI/PET group indicated that PET improved surgical decision-making because 24 (24.2 %) LRRCRCs that manifested on CT/MRI as equivocal lesions were later confirmed by PET as resectable recurrences, while 18 (19.4 %) LRRCRCs that manifested on CT/MRI as resectable lesions were later diagnosed by PET as more disseminated unresectable recurrences and precluded futile surgery.

CONCLUSION

PET alone can identify a subset (20.9 %) of LRRCRCs with less tumor burden for timely surgery; PET in combination with CT/MRI can better define the resectability of LRRCRCs. The positive impacts of PET can translate into better surgical outcomes, with enhanced safety and patient survival.

Use of Positron Emission Tomography to Detect Recurrence and Associations With Survival in Patients With Lung and Esophageal Cancers

BACKGROUND

Positron emission tomography (PET) scans are often used in cancer patients for staging, restaging, and monitoring for treatment response. These scans are also often used to detect recurrence in asymptomatic patients, despite a lack of evidence demonstrating improved survival. We sought to evaluate utilization of PET for this purpose and relationships with survival for patients with lung and esophageal cancers.

METHODS

Using national Surveillance, Epidemiology, and End Results (SEER) and Medicare-linked data, we identified incident patient cases from 2005 to 2009, with follow-up through 2011. We identified cohorts with primary lung (n = 97 152) and esophageal (n = 4446) cancers. Patient and tumor characteristics were used to calculate risk-adjusted two-year overall survival. Using Medicare claims, we examined PET utilization in person-years (to account for variable time in cohorts), excluding scans for staging and for follow-up of CT findings. We then stratified hospitals by quintiles of PET utilization for adjusted two-year survival analysis. All statistical tests were two-sided.

RESULTS

There was statistically significant variation in utilization of PET. Lowest vs highest utilizing hospitals performed .05 (SD = 0.04) vs 0.70 (SD = 0.44) scans per person-year for lung cancer and 0.12 (SD = 0.06) vs 0.97 (SD = 0.29) scans per person-year for esophageal cancer. Despite this, for those undergoing PET, lowest vs highest utilizing hospitals had an adjusted two-year survival of 29.0% (SD = 12.1%) vs 28.8% (SD = 7.2%) for lung cancer (P = .66) and 28.4% (SD = 7.2%) vs 30.3% (SD = 5.9%) for esophageal cancer (P = .55).

CONCLUSIONS

Despite statistically significant variation in use of PET to detect tumor recurrence, there was no association with improved two-year survival. These findings suggest possible overuse of PET for recurrence detection, which current Medicare policy would not appear to substantially affect.

Predictors of initial 18F-fluorodeoxyglucose-positron emission tomography indication among patients with colorectal cancer

OBJECTIVES

To evaluate the determinants of initial F-fluorodeoxyglucose (F-FDG)-PET indication following primary colorectal cancer diagnosis among patients who underwent surgery between January 2000 and December 2007 and who were observed at a single institution for at least 2 years after diagnosis.

METHODS

Of the 530 patients who underwent colorectal cancer resection, 113 patients received at least one F-FDG-PET following diagnosis. Outcome variables included indication and time of the first F-FDG-PET following diagnosis. Potential predictors included disease-level and patient-level characteristics. Univariate and multivariate regression analyses were performed.

RESULTS

Patients diagnosed later in the study period and patients with higher-stage disease were more likely to receive their first F-FDG-PET for initial staging (P<0.001 and P=0.016, respectively). Patients with lower-stage disease were more likely to receive their initial F-FDG-PET for suspected recurrence on conventional imaging. When performed more than 2 years after diagnosis, F-FDG-PET was more likely to be ordered for suspected recurrence either on the basis of conventional imaging or on the basis of patient symptoms/tumor markers (P=0.003 and 0.031, respectively). F-FDG-PET demonstrated disease progression in at least 50% of patients referred for each indication (P=0.037).

CONCLUSION

Higher utilization of F-FDG-PET may be appropriate among patients referred for a number of indications including: initial staging, particularly among those with higher-stage disease; suspected recurrence on conventional imaging among patients with lower-stage disease; and suspected recurrence more than 2 years after diagnosis. Further research is needed to verify these findings.

New pathways to medicare coverage for innovative PET radiopharmaceuticals: report of a medical imaging & technology alliance (MITA) workshop

PET and PET/CT have revolutionized the diagnosis, staging, and monitoring of treatment effect or recurrence for a wide range of cancers and shown promise for improving health outcomes for patients with cardiovascular and central nervous system diseases. However, this technology is challenged by insurance coverage policies that hinder patients' access to PET and discourage technologic innovation. Recently, the Medical Imaging & Technology Alliance (MITA), a Washington-based industry association, convened a workshop to consider new pathways for making decisions on Medicare coverage of new PET radiopharmaceuticals and imaging procedures that are currently subject to a national noncoverage decision, or "exclusionary rule." Stakeholders from the government, medical professional societies, academia, patient groups, and industry gathered to brainstorm alternatives to the national noncoverage decision and evaluate their potential to improve access and enhance innovation. Ultimately, MITA, on behalf of the PET community, expects to use the outcomes of the workshop to propose that the Centers for Medicare and Medicaid Services reconsider this current national noncoverage decision for PET and adopt a new framework for coverage.

PET/CT without capacity limitations: a Danish experience from a European perspective

OBJECTIVES

We report the 3-year clinical experience of a large new Danish PET/CT centre without capacity limitations in relation to national and European developments.

METHODS

The use of PET/CT in cancer was registered from early 2006 to early 2009 to judge the impact on patient management and to compare it with national and European trends.

RESULTS

6056 PET/CT examinations were performed in 4327 patients. Activity increased by 86 examinations per month compared with the same month the year before. Referrals came primarily from oncology (23.0%), haematology (21.6%), surgery (12.6%), internal medicine (12.7%) and gynaecology (5.5%). Referral indications were diagnosis (31.3%), staging (22.3%), recurrence detection (21.2%), response evaluation (17.0%) and other (8.2%). Response from nearly 60% of users showed that PET/CT caused a change in diagnosis and/or staging and/or treatment plan in 36.0% of cases. During the study period, there was a steep increase in the national use of FDG and in the European use of PET/CT.

CONCLUSIONS

We recorded a constantly increasing use of PET/CT that caused a change in diagnosis and/or staging and/or treatment plan in 36.0% of cases. In line with national and European trends this may suggest a shift in favour of functional rather than anatomical imaging.

Resected colorectal cancer among Medicare beneficiaries:adoption of FDG PET

PURPOSE

To investigate early adoption and potential predictors of postoperative utilization of fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) in patients who underwent colorectal cancer resection between July 2001 and December 2002 (the first 18 months of Centers for Medicare and Medicaid Services [CMS] coverage for FDG PET) and who were observed for 2 years from the date of surgery.

MATERIALS AND METHODS

This HIPAA-compliant study was exempt from institutional review board approval. Informed consent was waived. This was a retrospective cohort study of FDG PET utilization in patients with colorectal cancer following resection between July 1, 2001 and December 31, 2002. Utilization data were drawn from the Surveillance, Epidemiology and End Results-Medicare files during the first 2 years following colorectal surgery. The primary outcome measure was FDG PET utilization. Covariates included disease-, patient-, and hospital-level characteristics, as well as computed tomography (CT) utilization. Univariate and multiple regression analysis were performed.

RESULTS

Of 10630 patients (mean age, 77.5 years) who underwent resection for colorectal cancer during the study period, 1056 (10%) patients underwent at least one FDG PET examination in the 2-year period following surgery. A 41% relative increase in utilization of FDG PET was found among patients who underwent resection early in the study period compared with those who underwent resection late in the study period; this was a significant difference (P < .001). There was no change in CT utilization between these two groups (P = .302). The highest utilization of FDG PET was during the first 6 months following surgery. Significant predictors of higher FDG PET utilization included rectal cancer, later date of initial surgery, higher disease stage, older age, marital status, and lower comorbidity.

CONCLUSION

Substantial growth in utilization of FDG PET within 2 years of surgery was found among patients who underwent surgery during the first 18 months of approved CMS coverage, with the highest rates of utilization occurring within 6 months of surgery and lower rates occurring subsequently over the 2-year period following resection.

Impact of whole-body 18F-FDG PET on diagnostic and therapeutic management of Medical Oncology patients

AIM

Most studies evaluating positron-emission tomography (PET) impact on decision making are based on questionnaires sent to referring physicians, with low response rates and potential bias. Studies directly evaluating influence of PET on routine management of Medical Oncology patients are scarce.

PATIENTS AND METHODS

We retrospectively studied all patients evaluated by whole-body (18)F-FDG PET during 1 year in a Haematology/Oncology Department. We collected information regarding indication, PET results, modification of diagnostic and therapeutic management and adequacy of therapeutic changes.

RESULTS

One hundred consecutive patients having PET were evaluated. Diagnostic strategy was modified in 63% of patients (30% avoiding biopsy). Therapeutic management was modified by PET in 34% of cases: changes were classified as adequate in 30% and as inadequate in 4% of patients.

CONCLUSIONS

Our study shows a major impact of PET in the diagnostic and therapeutic management of cancer patients and supports its introduction as a routine diagnostic tool in Medical Oncology.

18F-FDG PET for posttherapy assessment of Hodgkin's disease and aggressive Non-Hodgkin's lymphoma: a systematic review

Although studies have shown that (18)F-FDG PET, when used to assess the response of malignant lymphoma after treatment, has a strong ability to predict relapse, its diagnostic accuracy in clinical practice remains unclear. The aim of this study was to systematically review the diagnostic accuracy of (18)F-FDG PET in detecting residual disease at the completion of first-line therapy of Hodgkin's disease (HD) and aggressive non-Hodgkin's lymphoma (NHL).

METHODS

We searched relevant articles from 1966 to July 2006 using MEDLINE, EMBASE, SCOPUS, Biological Abstracts, bibliographies, review articles, and textbooks without language restriction. One assessor (for non-English-language studies) or 2 assessors (for English-language studies) independently reviewed each article to abstract relevant study characteristics and results. Relevant individual patient data or subgroup data were provided by the investigators if they were unavailable from the publications. We estimated summary receiver operating characteristic curves and confidence regions for summary sensitivity and specificity.

RESULTS

Nineteen studies consisting of 474 HD and 254 aggressive NHL patients were included. These studies had heterogeneity and suboptimal methodologic quality and reporting. Reported ranges for the sensitivity and specificity of (18)F-FDG PET in predicting disease relapse were 0.50-1.00 and 0.67-1.00, respectively, for HD and 0.33-0.77 and 0.82-1.00, respectively, for NHL. These estimates were similar when conventional imaging tests showed a residual mass. For HD studies, the summary receiver operating characteristic curves were similar irrespective of whether a residual mass was detected by conventional tests. Factors explaining the variability of diagnostic estimates were not identified.

CONCLUSION

Although currently available evidence is still limited, (18)F-FDG PET seems to have good diagnostic accuracy for assessing residual HD at the completion of first-line treatment. Clinical data on this use of (18)F-FDG PET for aggressive NHL are more limited. Prospective studies with a more rigorous research design, conduct, and reporting would more reliably reveal the clinical diagnostic accuracy of this imaging modality.

Medicare coverage of PET for cervical cancer

Positron emission tomography (PET) with 2-[(18)F]fluoro-2-deoxyglucose (FDG) has had a major impact on the initial evaluation and follow-up of patients with cancer. Yet because Medicare coverage standards differ from the US Food and Drug Administration's approval requirements, FDG-PET has not been covered by the Centers for Medicare and Medicaid Service (CMS) for general oncologic indications. Instead, starting in 1995, CMS began to cover FDG-PET for specific cancers and indications after an individualized review of the evidence of benefit in the scientific literature. The CMS limited coverage to circumstances in which results could be expected to change patient outcomes and in which FDG-PET could either help avoid an invasive procedure or would replace other imaging studies or when the results of prior conventional imaging were inconclusive. To expand the coverage of FDG-PET for cancer imaging, the Academy of Molecular Imaging began working with various organizations to submit applications for coverage of several additional cancers. In 2003, Washington University investigators requested FDG-PET coverage for the staging and restaging of cervical cancer. In January 2005, CMS issued a decision memorandum covering FDG-PET for patients with newly diagnosed cervical cancer subsequent to conventional imaging that is negative for extrapelvic metastasis. The CMS also announced a new approach for evaluating new technology and indicated its intent to cover FDG-PET for all oncologic indications as part of a national PET data registry. With this approach, FDG-PET for a presently noncovered indication will now be covered, if an attending physician completes a brief case report both before and after the PET study. The CMS is attempting to implement the registry by late 2005.

The National Oncologic PET Registry: Expanded Medicare Coverage for PET Under Coverage with Evidence Development

OBJECTIVE

The purpose of this article is to review the recent expansion of Medicare coverage for 18F-FDG PET for certain cancer indications under the Centers for Medicare & Medicaid Services' new Coverage with Evidence Development (CED) policy and to describe the specific operational mechanics of the National Oncologic PET Registry (NOPR).

CONCLUSION

The NOPR will make possible a more accurate assessment of the actual influence of PET on patient management across a wide spectrum of cancer indications. By linking access to PET for virtually all Medicare beneficiaries to the collection of clinically valuable evidence, the NOPR represents the cutting edge of the CED approach.

Integrated PET/CT as a first-line re-staging modality in patients with suspected recurrence of ovarian cancer

PURPOSE

The aims of this study were to compare CT with PET/CT results in patients with suspected ovarian cancer recurrence and to assess the impact of the PET/CT findings on their clinical management.

METHODS

Thirty-two consecutive patients with suspected ovarian cancer recurrence were retrospectively included in the study. Abdominal contrast-enhanced CT and PET/CT with [(18)F]FDG, in addition to conventional follow-up, were performed in all 32 patients. After the comparison between CT and PET/CT results, based on clinical reports, changes in the clinical management of patients (intermodality changes) due to PET/CT information were analysed.

RESULTS

Twenty of the 32 patients were positive at CT (62.5%) versus 29 (90.6%) at PET/CT. Intermodality changes in management, i.e. use of a different treatment modality, after PET/CT examination were indicated in 14/32 (44%) patients. In particular, before PET/CT study, the planned management was as follows: wait-and-see in 7/32 (22%), further instrumental examinations in 4/32 (12%), chemotherapy in 10/32 (31%), diagnostic surgical treatment in 6/32 (19%) and surgical treatment in the remaining 5/32 (16%). After PET/CT study, wait-and-see was indicated in 1/32 (3%), further instrumental examinations in 7/32 (22%), chemotherapy in 16/32 (50%), diagnostic surgical treatment in 2/32 (6%) and surgical treatment in the remaining 6/32 (19%).

CONCLUSION

Integrated PET/CT could detect tumour relapse in a higher percentage of patients than could CT. A change in the clinical management was observed in 44% of cases when PET/CT information was added to conventional follow-up findings.

The role of anatomic and functional staging in myeloma: description of Durie/Salmon plus staging system

Staging is the cornerstone of baseline myeloma evaluation. New imaging techniques such as magnetic resonance imaging (MRI), whole body FDG-PET scanning and whole body CT (combined with PET directly or by fusion) offer the opportunity to precisely stage patients by anatomic and functional techniques. The new Durie/Salmon PLUS staging system integrates these new imaging techniques into a new generation of anatomic and functional myeloma staging. It is possible to discriminate between the impact of tumour burden (myeloma cell mass) and other prognostic factors. This refined classification by stage and prognostic category is increasingly important in clinical trials. The value of clinical staging in patient management is emphasized both in discrimination of early disease status and clearer identification of poorer risk of Stage II and III disease. Wider use of newer imaging will undoubtedly enhance analysis of new trials incorporating novel agents.

Utility of FDG-PET/CT in follow-up of children treated for Hodgkin and non-Hodgkin lymphoma

Positron emission tomography using F-flurodeoxyglucose (FDG-PET) is considered an excellent tool for staging and monitoring disease status in adults with lymphoma. We retrospectively reviewed results of PET/CT and diagnostic computed tomography (CT) scans performed during follow-up after completion of therapy in 41 children <18 years of age with Hodgkin lymphoma and non-Hodgkin lymphoma. PET/CT scan with uptake greater than that of the liver was considered positive. Uptake that increased over the background but less than in the liver was equivocal. Clinical outcomes were obtained from medical records. Thirteen (32%) had a positive PET/CT scan and an equal number had equivocal scans in a median follow-up of 2.3 years. Diagnostic CT scans revealed new findings in 13 (32%) and persistent abnormalities in 21 (51%) of the children. Five children developed recurrent disease, and one developed a second cancer. No children with equivocal positivity developed recurrent disease. PET/CT scan was 95% sensitive, with a positive predictive value (PPV) of 53%. Diagnostic CT was 79% sensitive, with a PPV of 52%. We conclude that a negative PET/CT scan during routine follow-up for lymphoma in children strongly suggests absence of recurrence but a positive PET/CT and diagnostic CT scans have low PPV and should be interpreted with caution in this setting.

Significant clinical impact and prognostic stratification provided by FDG-PET in the staging of oesophageal cancer

PURPOSE

To evaluate the clinical impact of FDG-PET in staging oesophageal cancer and whether this information improves prognostic stratification.

METHODS

Impact was based on comparison of a prospectively recorded pre-PET plan with post-PET treatment in 68 consecutive patients undergoing primary staging. Survival was analysed using the Kaplan-Meier product limit method and the Cox proportional hazards regression model.

RESULTS

FDG-PET findings impacted on the management of 27/68 patients (40%): in 12 therapy was changed from curative to palliative and in three from palliative to curative, while in 12 other patients there was a change in the treatment modality or delivery but not in the treatment intent. The median survival was 21 months, with post-PET stage and treatment intent both strongly associated with survival (p<0.001). Conventional stage was not able to clearly stratify this population.

CONCLUSION

The use of FDG-PET for primary staging of oesophageal cancer changed the clinical management of more than one-third of patients and provided superior prognostic stratification compared with conventional investigations.

The contribution of PET/CT to improved patient management

With the introduction of both SPET/CT and PET/CT, multimodality imaging has truly entered routine clinical practice. Multiple slice spiral CT scanners have been incorporated with multiple detector gamma cameras or PET systems, such that the benefit of these modalities can be achieved in one patient sitting. The subject of this manuscript is PET/CT and its impact on patient management. Applications of PET/CT span the whole field of medical and surgical oncology since very few cancers do not take up the labelled glucose tracer, (18)F-FDG. Given the contrast achieved, high-quality data can be obtained with FDG PET/CT. This technology has now spread worldwide and has been the subject of intense interest, as witnessed by the vast body of published evidence. In this short overview, only a brief discussion of the main clinical applications is possible. Novel applications of PET/CT outside the field of oncology are expected in the near future.

Early clinical experience and impact of 18F-FDG PET

PURPOSE

To determine the influence and impact of [F]- fluorodeoxyglucose positron emission tomography (FDG PET) in Denmark.

METHODS

A standardized questionnaire was sent to the referring physicians of 743 consecutive cases between January 2000 and December 2001. The questionnaire was designed to determine whether and how the results of the FDG PET imaging changed patient management.

RESULTS

The response rate was 71% (524 responded). The distribution of all responding physicians included 26 different specialities. The majority were from haematology (23%), oncology (20%), plastic surgery (17%) and neurology (10%). The primary diagnoses at referral was in the field of oncology (94%), with lymphoma (24%), melanomas (20%), unknown primary neoplasms (13%), nervous system neoplasms (9%), lung cancer (6%) and cancer of the digestive system (4%). FDG PET imaging resulted in a change in the patients' management in 224 cases (43%). Of these, surgery was affected in 88 cases. Chemotherapy was affected in 71 cases and radiation therapy in 54 cases. In patients where the intended plan of management was not changed, 78% of the physicians stated that FDG PET was nevertheless clinically helpful; for example confirmed the diagnosis, helped staging, changed treatment plan or confirmed treatment of choice. Physicians indicated a general satisfaction with FDG PET imaging in 86% of the cases.

CONCLUSION

This survey-based study indicates that FDG PET imaging has a major impact on patient management, contributing to changes in management in 43% of cases. The present study also demonstrates that referring physicians are generally satisfied with FDG PET imaging in 86% of the cases.