Benefit of PET or PET/CT in recurrent bowel cancer is not proven
For patients in whom a recurrence of bowel cancer is suspected, the study data currently available allow no robust conclusions as to the advantages and disadvantages of using positron emission tomography (PET), alone or in combination with computed tomography (CT). This is because no studies have directly compared the benefits of these imaging techniques in recurrent colorectal carcinoma (bowel cancer) with conventional diagnostic techniques. Although PET or PET/CT show a higher diagnostic accuracy, i.e. in certain cases recurrences can be detected more reliably, it is still unclear how this actually affects patient-relevant outcomes such as quality of life. This is the conclusion of the final report of the German Institute for Quality and Efficiency in Health Care (IQWiG) published on 24th October 2012.
More reliable diagnosis ought to improve treatment
Bowel cancer is the second most common malignant tumour in both men and women. Every year, more than 65,000 people are diagnosed with the disease in Germany and more than 25,000 die from it annually. About 80% of the recurrences occur in the first two years after surgery for bowel cancer. After 5 years, virtually no more recurrences are found. These can arise at the original site - the bowel - or as secondary tumours ("metastases"), for example in the liver. Follow-up after surgery should therefore last for 5 years.
Many experts hope that when a recurrence is suspected, an examination using PET or PET/CT alone or in combination with other methods is better able to distinguish between benign and malignant tumours (recurrence diagnostics) and, if applicable, to classify the stage of the latter correctly, i.e. to determine how advanced the cancer is (recurrence staging). This information should enable patients to be given better treatment recommendations.
Benefits for patients crucial
IQWiG therefore searched the international literature for studies which had examined the consequences of a diagnostic intervention using PET or PET/CT on health aspects of direct relevance to patients. For example, the results of the diagnostic investigation - and appropriately tailored treatment - could contribute to better chances of survival for patients, spare them unnecessary operations or further diagnostic interventions, or improve their quality of life.
As requested by the contracting agency, the Federal Joint Committee (G-BA), this report was to focus on those patients in whom a recurrence had already been detected or in whom there was at least a justified suspicion thereof.
The only benefit study proved to be unsuitable
In its final assessment IQWiG was unable to include any studies that had investigated benefits of relevance to patients. For the preliminary report, i.e. the preliminary results, IQWiG had evaluated one study. This addressed the question as to whether, in patients in whom potentially operable liver metastases were suspected, unnecessary laparotomies (surgical opening of the abdomen) could be avoided if a PET investigation took place following a diagnostic intervention using contrast-medium-enhanced CT.
As IQWiG has since discovered after requesting information from authors, this study was, however, unsuitable for deriving any conclusions regarding benefit. This was because - in contrast to the original plan - the decision to operate or not was not allowed to be made in dependence upon the PET results. The independent advisory committee had advised against this procedure on ethical grounds. But information on this important change in the conduct of the study was provided neither in the publication of the study results nor by entry in a clinical trials registry.
In certain cases, PET/CT can detect recurrences more reliably
For the preliminary report, IQWiG had already made an additional search for studies in which the diagnostic accuracy and prognostic power of PET or PET/CT had been compared with other diagnostic techniques. This referred to the question as to how often a PET investigation provides a correct result. On the one hand, true malignant tumours should be overlooked as rarely as possible, while on the other, false suspicions should not be aroused.
The results of a total of 5 evidence syntheses and 13 individual studies regarding this question could be evaluated. The conclusion on recurrence detection was as follows: PET and PET/CT appear capable of detecting or excluding recurrences more reliably than a conventional diagnostic intervention consisting solely or predominantly of CT. This applies particularly to local recurrences and distant metastases. It is not possible to state with certainty whether PET and PET/CT differ in terms of their diagnostic accuracy.
Further study results needed
Important questions in relation to PET technology remain unanswered. For example, it has not yet been examined whether the higher accuracy of PET or PET/CT has a positive effect on mortality, the burden of disease or quality of life.
As long as this deficiency remains, a patient-relevant benefit of PET or of PET/CT as a supplementation to a suspicion-driven diagnostic investigation with conventional methods is not proven. For instance, it is particularly doubtful whether a recurrence detected by using PET or PET/CT can actually be better treated and thereby produce a perceptible advantage for patients. Experts are therefore eagerly awaiting the results of a Canadian study with more than 400 patients, which is to be published shortly.
Missing information can lead to false conclusions
Stefan Lange, the Deputy Director of IQWiG, commented on the new information gained by IQWiG during the assessment procedure of the study on laparotomies: "The fact that the only benefit study on PET turned out to be unsuitable is extremely regrettable. The rupture of the logical link between diagnosis and treatment devalued the study results." As Lange explained, a basic principle of medicine is that a diagnostic intervention is only of benefit if it enables patients to receive more tailored treatment. The fact that the study authors (Ruers et al., 2009 / Nijmegen University, The Netherlands) had also failed to inform about a fundamental change in their procedure was unacceptable. As Lange stated, because of this there is a danger that researchers, doctors and patients will draw the wrong conclusions.
Procedure of report production
IQWiG published the preliminary results in the form of the preliminary report in September 2011 and interested parties were invited to submit comments. At the end of the commenting procedure, which included an oral scientific debate including parties who had submitted comments, the preliminary report was revised and sent as a final report to the contracting agency, the Federal Joint Committee (G-BA), in August 2012. The written comments were published in a separate document at the same time as the final report. The report was produced in collaboration with external experts.
- Benefit of PET and PET/CT in ovarian cancer is not proven Aug 08, 2012 | not rated yet | 0
- Benefit of PET in patients with head and neck tumors cannot be assessed Apr 29, 2011 | not rated yet | 0
- Malignant brain tumors: Benefit of PET and PET/CT in the detection of recurrences is not assessable Jan 19, 2011 | not rated yet | 0
- FDG-PET/CT plays a definite role in detecting colorectal cancer recurrences May 05, 2010 | not rated yet | 0
- Routine follow-up scans can detect head and neck cancer recurrences earlier Jan 26, 2012 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
How can there be a term called "intestinal metaplasia" of stomach
9 hours ago Hello everyone, Ok Stomach's normal epithelium is simple columnar, now in intestinal type of adenocarcinoma of stomach it undergoes "intestinal...
Pressure-volume curve: Elastic Recoil Pressure don't make sense
May 18, 2013 From pressure-volume curve of the lung and chest wall (attached photo), I don't understand why would the elastic recoil pressure of the lung is...
If you became brain-dead, would you want them to pull the plug?
May 17, 2013 I'd want the rest of me to stay alive. Sure it's a lousy way to live but it beats being all-the-way dead. Maybe if I make it 20 years they'll...
MRI bill question
May 15, 2013 Dear PFers, The hospital gave us a $12k bill for one MRI (head with contrast). The people I talked to at the hospital tell me that they do not...
Ratio of Hydrogen of Oxygen in Dessicated Animal Protein
May 13, 2013 As an experiment, for the past few months I've been consuming at least one portion of Jell-O or unflavored Knox gelatin per day. I'm 64, in very...
Alcohol and acetaminophen
May 13, 2013 Edit: sorry for the typo in the title , can't edit I looked around on google quite a bit and it's very hard to find precise information on the...
- More from Physics Forums - Medical Sciences
More news stories
A study of veterans at high risk for developing lung cancer shows that low-dose computed tomography (LDCT) can be highly effective in helping clinicians spot tiny lung nodules which, in a small number of patients, may indicate ...
Cancer 1 hour ago | not rated yet | 0
An attack on glioblastoma brain tumor cells that uses a modified poliovirus is showing encouraging results in an early study to establish the proper dose level, researchers at Duke Cancer Institute report.
Cancer 2 hours ago | not rated yet | 0
The surgical management of non-small cell lung cancer (NSCLC) in U.S. hospitals varies widely depending on the race of the patient, according to a new study.
Cancer 6 hours ago | not rated yet | 0
Treatment with an Alpha-1 proteinase inhibitor (A1-PI), a naturally occurring protein that protects lung tissue from breakdown and protects the lung's elasticity, is effective in slowing the progression of emphysema in patients ...
Cancer 7 hours ago | not rated yet | 0
Scientists from Nanyang Technological University (NTU) and Lund University, Sweden, have bioengineered a novel molecule which has been proven to successfully kill tumour cells.
Cancer 7 hours ago | 5 / 5 (1) | 0
A drug commonly used to treat depression and anxiety may improve a stress-related heart condition in people with stable coronary heart disease, according to researchers at Duke Medicine.
30 minutes ago | not rated yet | 0 |
(HealthDay)—The overall health of Americans isn't improving much, with about six in 10 people either overweight or obese and large numbers engaging in unhealthy behaviors like smoking, heavy drinking or ...
40 minutes ago | not rated yet | 0
(HealthDay)—In 2008 to 2010, the prevalence of key health behaviors among U.S. adults varied, with about one in five adults current smokers and 62.1 percent overweight or obese, according to a report presented ...
30 minutes ago | not rated yet | 0
(HealthDay)—Factors such as increased case finding may explain why Michigan had half of the total spinal infections associated with contaminated methylprednisolone acetate in the recent fungal meningitis ...
20 minutes ago | not rated yet | 0
Early use of tracheostomy for mechanically ventilated patients not associated with improved survival
For critically ill patients receiving mechanical ventilation, early tracheostomy (within the first 4 days after admission) was not associated with an improvement in the risk of death within 30 days compared to patients who ...
30 minutes ago | not rated yet | 0
(HealthDay)—Three-quarters of public schools in the metro Atlanta area contain microbes, including bacteria indicating the presence of fecal matter, according to research published in the May 17 issue of ...
10 minutes ago | not rated yet | 0