Cancer Treatment Today » Imaging

Staging rectal cancer with MRI

M Levin, MD — Mon, 24 Jun 2013 12:06:59 +0000

With the advent of powerful gradient coil systems and high-resolution surface coils, magnetic resonance imaging (MRI) has come into tis own in being able to assess the relationship of a rectal tumor to surrounding organs and tissues. MRI is currently the only imaging modality that is highly accurate in predicting whether or not it is likely that a tumor can be resected without leaving cells behind and, therefore, provides important information for planning effective surgery versus chemotehrapy and radiation, especially in patients with advanced rectal cancer. It enables selection of surgery versus chemotherapy and radiation as treatment for localized rectal cancer.

MRI is recommended in selected cases by the European Guideline. One notable difference between this NICE guideline and the American NCCN guidelines is the use of ultrasound versus magnetic resonance imaging (MRI) for rectal cancer staging. In the US ultrasound is used more frequently for staging it and has advantages for discerning early and small cancers. Nevertheless, staging with MRI should still be considered medically appropriate even in the USA.

For Professional version see here

FDG PET for neuroendocrine cancer

M Levin, MD — Thu, 20 Sep 2012 14:31:45 +0000

PET that uses FDG (a type of tagged sugar) is not all that sensitive in neuroendocrine cancers(NET). This means that it may not pick up some neuroendocrine cancers. Specificity means that what it does pick up is really cancer and not some other false positive. However, other imaging modalities also had disadvantages as well as advantages. One study revealed that for neuroendocrine tumors, PET that used 18F-FDOPA was more accurate (sensitivity, 100%; specificity, 91%) in the detection of skeletal lesions than octreotide scintigraphy or CAT scan but was insensitive (sensitivity, 20%; specificity, 94%) in the lung, ostensibly because respiratory motion during image acquisition degrade the accuracy of PET. Octreotide scintigraphy yielded its best results in the liver (sensitivity, 75%; specificity, 100%); however, it was less accurate than PET in all organs. However, 18F-FDOPA PET is less sensitive than FDG PET and standard imaging procedures for the staging of small cell lung cancer. Popperl et al recommends that 18F-FDG should be preserved for less differentiated tumors, while amine precursors and somatostatin analogs contrast should be implemented in the diagnostic process of well-differentiated NET. NCCN on p. MS-12 does not recommend FDG PET for neuroendocrine cancer.

Read the Professional version here.

MRI for back pain

M Levin, MD — Fri, 07 Sep 2012 22:12:49 +0000

Back pain is very common. It widely acknowledged that there should be definitive standar5ds on when and how frequently MRI scans should be performed to assess back pain. The American College of Physicians (ACP) and the American Pain Society (APS) have issued a comprehensive joint clinical practice guideline for the diagnosis and treatment of low back pain, which is published in the October 2, 2007 issue of the Annals of Internal Medicine.

For patients with nonspecific low back pain, clinicians should not routinely order imaging studies, including radiographs, computerized tomography (CT) scans, magnetic resonance imaging (MRI), or other diagnostic tests. These tests should be used to evaluate only those patients who have severe or progressive neurologic deficits or who are suspected to have cancer, infection, or other underlying condition as the cause of their low back pain.

For patients with nonspecific low back pain, clinicians should not routinely perform imaging studies, including radiographs, CT scans, and MRI, or other diagnostic tests (strong recommendation; moderate-quality evidence). These patients should be treated and imaging considered if conservative treatment fails.

Patients with severe or progressive neurologic deficits, or in whom history and physical examination suggest cancer, infection, or other underlying condition as the cause of their low back pain, should undergo imaging studies and other appropriate diagnostic tests (strong recommendation; moderate-quality evidence).

Patients with persistent low back pain and signs or symptoms of radiculopathy or spinal stenosis should undergo MRI or CT only if positive results would potentially lead to surgery or epidural steroid injection for suspected radiculopathy. In choosing an imaging procedure, MRI is preferred to CT (strong recommendation; moderate-quality evidence).

For Professional version see here

PET for cholangiocarcinoma – pro

M Levin, MD — Tue, 28 Aug 2012 00:30:18 +0000

Cholangiocarcinomas are not simple to image because they are located in an area of multiple other organs and there is often associated inflammation and anatomic variation. There are also only a few studies of PET for cholangiocarcinomas and conclusions vary. In a study by Kim et al, FDG PET was not found to be specific enough in detecting hilar cholangiocarcinomas, an observation ascribed to small tumor size or to fibrous or mucinous components of the lesion . Most peripheral cholangiocarcinomas show ring-shaped FDG uptake due to excessive desmoplastic response within the tumor and neovascularity at the periphery. However, these findings are not specific to cholangiocarcinomas, since any lesion with central necrosis can mimic this pattern. Fritscher-Ravens et al found FDG PET more useful in detecting metastases to lymph nodes, the liver, and other distant sites. However, they could not differentiate malignant from benign lesions, since false-positive FDG uptake was seen in granulomatous inflammatory lesions and there were false-negative results in non-FDG-avid mucinous cholangiocarcinomas. NCCN on pp GAL-2-4 only lists CT scans and MRI. The 2012 Bristish update of 2012 does not mention PET. The 2014 guidelines byBridgewater et al says: “Prior to surgical resection,PETscanning may be con-

sidered to help rule out an occult primary as well as to rule out otherwise occult metastatic disease.“.

A recent consensus statement concluded: “PET-CT is recommended in the preoperative staging of intrahepatic and extrahepatic CCA.” In regard to restaging, PET is not well established and NCCN does not list PET in its guidelines

S. Breitenstein, C. Apestegui, and P.-A. Clavien, Positron emission tomography (PET) for cholangiocarcinoma, HPB (Oxford). 2008; 10(2): 120121.

Jadvar H, Henderson RW, Conti PS. F-18]fluorodeoxyglucose positron emission tomography and positron emission tomography: computed tomography in recurrent and metastatic cholangiocarcinoma. J Comput Assist Tomogr. 2007;31:2238.

Garcea G, Ong SL, Maddern GJ. The current role of PET-CT in the characterization of hepatobiliary malignancies.HPB (Oxford). 2009 Feb;11(1):4-17.

Olthof SC, Othman A, Clasen S, Schraml C, Nikolaou K, Bongers M. Imaging of Cholangiocarcinoma. Visc Med. 2016;32(6):402410.

Rahnemai-Azar AA, Pandey P, Kamel I, Pawlik TM. Monitoring outcomes in intrahepatic cholangiocarcinoma patients following hepatic resection. Hepat Oncol. 2016;3(4):223–239.

NCCN, Cholangiocarcinoma, 2019

Posttreatment surveillance after hepatic metastases resection for colorectal cancer

M Levin, MD — Fri, 24 Aug 2012 19:54:24 +0000

Since the appearance of effective new drugs for colorectal cancer and more aggressive surgical approaches to resecting isolated metastases, many patients who had metastatic cancer are now free of disease for an extended period of time. There are few guidelines on how to follow such patients it is fairly new situation and there are no mature studies. For high risk non-metastatic colon cancer, NCCN guidelines recommend annual CT of chest, abdomen and pelvis. Post-surgery surveillance is similarly warranted following resection of isolated colorectal cancer metastases because a minority of the recurrent patients can be treated with metastatectomy from the liver and lung, and some of them will enjoy long-term survival and even cure. The liver is the only site of recurrence in approximately 35 to 40 percent. Five-year survival rates up to 43 percent are reported following repeat liver resection for a second recurrence, with acceptable morbidity and perioperative mortality. Clearly, these patients need to be followed so as to intervene early after new metastases appear.

The impact of CT-based follow-up for the detection of resectable disease recurrence was addressed in a review of 705 patients who underwent resection of isolated colorectal cancer liver metastases at a single institution over a 14-year period. All were followed with a similar surveillance protocol, which included outpatient clinical examinations at 3, 6, 12, 18, and 24 months, and annually thereafter, with measurement of CEA and CA 19-9 levels at each visit. In addition, all patients had CT of the thorax, abdomen and pelvis every three months for the first two years, at six monthly intervals for three more years, then annually from year six to ten.

Of the 444 patients with a recurrence diagnosed on a surveillance CT, 404 were detected within two years. The site of recurrent disease was liver only in 36 percent, outside of the liver only in 38 percent, and both in the liver and in other organs in 26 percent. The authors did not report how many recurrences were detected by serum tumor markers versus CT scans.

In total, recurrent disease was treated surgically in 124 patients. At every time point (within one year of original surgery, one to two years, beyond two years), those patients treated by liver and/or lung resection had significantly better median survival than did those who received palliative chemotherapy alone. The mean number of scans performed per resectable recurrence was 35.3, and the cost per life-year gained was £2883, a value that compares favorably to other cost-effectiveness ratios that are considered acceptable in the US and elsewhere. UPTODate recommends the following surveillance strategy for patients with stage IV disease who are rendered surgically NED (no evidence of disease):

CEA every three months for two years, then every six months for three to five years

CT of the chest/abdomen and pelvis every three to six months for two years, then every 6 to 12 months up to a total of five years
Colonoscopy in one year; if no advanced adenoma repeat in three years, then every five years; if advanced adenoma is found, repeat in one year

Read the Professional version here.

PET for glioblastoma

M Levin, MD — Fri, 24 Aug 2012 18:03:47 +0000

PET is more and more frequently used to visualize brain cancers. However, PET is not medically appropriate to follow glioblastoma because it not supported by credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community. PET for brain cancer is not included in the NCCN guidelines and CMS does not cover PET for this diagnosis. Occasionally, PET can provide information to differentiate tumor necrosis from tumor progression. Tumor necrosis is when a cancer dies after being treated. The sensitivity of PET for differentiating necrosis and tumor progression is 80%–90% and the specificity is 50%–90%. Causes of false-negative PET results include recent radiation therapy, low grade, and small tumor volume. PET may be false positive in nonmalignant inflammatory processes and subclinical seizure activity. The question of hypermetabolic foci of radiation injury as a cause of false-positive scans requires further investigation. Other issues requiring further study are the optimal timing of PET after radiation and chemotherapy and the accuracy of PET in tumors other than high-grade gliomas.

A 2010 guideline by Laperrier says: “Positron emission tomography (PET) is not recommended for the determination of diagnosis or grading in gliomas. A recommendation cannot be made for or against the use of PET or positron emission tomography/computed tomography (PET/CT) in the assessment of patients with recurrent gliomas because of insufficient evidence. Positron emission tomography (PET) is not recommended for the determination of diagnosis or grading in gliomas. A recommendation cannot be made for or against the use of PET for the assessment of treatment response in gliomas because of insufficient evidence. A recommendation cannot be made for or against the use of PET or positron emission tomography/computed tomography (PET/CT) in the assessment of patients with recurrent gliomas because of insufficient evidence. Positron emission tomography (PET) is not recommended for the determination of diagnosis or grading in gliomas. A recommendation cannot be made for or against the use of PET for the assessment of treatment response in gliomas because of insufficient evidence. A recommendation cannot be made for or against the use of PET or positron emission tomography/computed tomography (PET/CT) in the assessment of patients with recurrent gliomas because of insufficient evidence.”
It is not clinically appropriate in terms of type, frequency, extent, site and duration and considered effective for the condition in question as per literature and guidelines

Read the Professional version here.

Breast tomosynthesis: a new mammography

M Levin, MD — Fri, 24 Aug 2012 17:59:49 +0000

Breast tomosynthesis is a 3-dimensional (3-D) imaging technology that involves acquiring images of a compressed breast at multiple angles during a short scan. It is more comfortable than standard mammography. The individual images are then reconstructed into a series of thin high-resolution slices that displayed individually or in a dynamic movie-like mode. Tomosynthesis can reduce or eliminate the tissue overlap effect. While holding the breast stationary, images are acquired at a number of different x-ray source angles. Objects at different heights in the breast project differently for each angle. The final step in the tomosynthesis procedure takes advantage of this fact and reconstructs the data to generate images that enhance objects from a given height by appropriate shifting of the projections relative to one another. Tomosynthesis has many properties that make it suitable as a modality for screening, including good diagnostic performance, short examination time and low radiation dose. It may become a strong competitor to the current gold standard breast screening modality, i.e. mammography. At the same time, theoretical advantages have not yet been shown to translate into clinical advantage or even equivalence to standard mammography.

Read the Professional version here.

PET for salivary gland cancers

M Levin, MD — Fri, 24 Aug 2012 14:53:31 +0000

The clinical utility of 18F-FDG PET in evaluating salivary gland malignancies has not been well defined. First we need to know how sensitive and specific PET can be and then a variety of issues regarding its role in staging, restaging and surveillance have to be resolved. The largest study by Hong-Lyel was only in 34 patients. He found that the sensitivity of 18F-FDG PET and CT for detecting primary tumors was 31 of 34 (91.2%) and 27 of 34 (79.4%), respectively. In the other 7 patients, CT was unable to detect definitive primary mass lesions in 5 patients, and lesions in 2 patients appeared to be multiple metastases from unknown primary sites. Otehr studies had a similar number of patients with similar results. There are no comparative studies of CT versus PET. It is also not known whether surveillance is at all helpful in these cancers. Two referenced 2012 studies dealt with PET’s ability to stage the neck or distinguish benign form malignant tumors. These studies can be found in the professional version.

To see the Professional version, please click here

PET for neuroendocrine cancer

M Levin, MD — Fri, 24 Aug 2012 13:35:26 +0000

FDG PET is not all that sensitive in neuroendocrine cancers(NET). This may relate to how neuroendocrine cancer takes up FDG in comparison to other radio-labels used for PET scanning. One study revealed that for neuroendocrine tumors, 18F-FDOPA scanning was more sensitive and accurate (sensitivity, 100%; specificity, 91%) in the detection of skeletal lesions than octreotide scintigraphy or CT but was not sensitive (sensitivity, 20%; specificity, 94%) in the lung, ostensibly because of respiratory motion during image acquisition. Octreotide scintigraphy yielded its best results in the liver (sensitivity, 75%; specificity, 100%); however, it was less accurate than FDOPA PET in all organs. However, 18F-FDOPA PET is less sensitive than FDG PET and standard imaging procedures for the staging of small cell lung cancer. Popperl et al recommends that 18F-FDG should be preserved for less differentiated tumors, while amine precursors and somatostatin analogs should be used for PET scanning in the diagnostic process of well-differentiated NET. NCCN on p. MS-12 does not recommend FDG PET.

Read the Professional version here.

MRI to Assess Bone Marrow Blood Flow

M Levin, MD — Mon, 20 Aug 2012 18:35:12 +0000

Among the new spinoffs of MRI technology is the recently developed method of assessing bone marrow flow, which can provide valuable information on the abnormal cells in the marrow in conditions such as leukemia or multiple myeloma. IT is also being studies in conditions such as prostate cancer that can involve the marrow. The most common method to measure perfusion in the body using MRI is T1-weighted dynamic contrast enhancement (DCE-MRI). The analysis of DCE-MRI data allows determining the perfusion and permeability of a biological tissue. Because this is a non-invasice method, ot can be regularly repeated. So, for example, if flow increases in the marrow after chemotherapy, there may have been a response to treatment.

This is an exciting new develpment but the technology itself is still being refined and tested. Few papers have appeared that clearly define its role in assessment of therapy and prognostic significance. It is already being studied in various cancers that invade the marrow as well as in the assessment of fractures and osteoporosis but much more work needs to be done before it will become widely accepted.

Read the Professional version here.