ASCO Studies Support Limited Use of 'Routine' Imaging 


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The overuse of imaging in oncology workup and surveillance is a timely concern, as health-care dollars shrink and the risk for second malignancies becomes clearer. At this year’s ASCO Annual Meeting, several studies showed that although many routine imaging studies may be unnecessary, physicians can be slow to adopt new recommendations.

Impact of ASCO ‘Top 5’ on Breast Cancer Imaging

In the workup of women diagnosed with breast cancer, local practice patterns have not been affected by the recently published ASCO recommendation for limited imaging, Canadian investigators showed.1

“Imaging for metastatic disease remains overutilized in stage I and II disease,” said Demetrios Simos, MD, of the Ottawa Hospital Research Institute and University of Ottawa. He noted that since most patients will have no suspicious findings, metastatic disease is unlikely to be detected by perioperative imaging. Excessive imaging is expensive, creates anxiety for the patient, and can delay treatment, he said.

Evidence-based guidelines for radiologic staging generally state that in the absence of findings suggestive of distant metastases, focused radiologic staging should be limited to patients with at least pathologic stage II disease. In keeping with published guidelines, ASCO has included the limited use of imaging in early breast cancer among its “Top 5 List” for fiscal responsibility. The study examined whether this “Top 5” recommendation has impacted practice patterns.

Investigators reviewed the charts of 200 patients, 100 before and 100 after the recommendation, for which they found 614 imaging tests reported. Overall, 83.5% of patients had at least one imaging test to look for metastatic disease, including 83% before the ASCO recommendation and 84% after. Metastastic lesions, however, were detected in only 2 of the 200 patients, and both had stage III disease, Dr. Simos ­reported.

The local Cancer Care Ontario evidence-based guideline for staging tests in primary breast cancer recommends no routine imaging for patients with stage I disease. However, of 98 stage I patients, 55 received chest x-rays, 57 received bone scans, and 46 received abdominal imaging. A similar pattern emerged for stage II patients, although bone scans were actually reduced in this group. About half of stage III patients received CT scans of the chest, abdomen, and pelvis, where none of these would be ­recommended.

“The purpose of the study was to not only quantify and report the amount of imaging done—excessive according to the guidelines—but also to see if there was any change in physician practice pattern brought about by the ASCO ‘Top 5’ publication,” Dr. Simos explained to The ASCO Post. “We showed that relative to the guidelines, imaging is overused with minimal yield and that there was no real change in this practice following the ASCO ‘Top 5’ publication.”

Intense Follow-up after Colorectal Cancer Resection

In the postsurgical follow-up of primary colorectal cancer patients, regular measurement of carcinoembryonic antigen (CEA) and regular CT scanning were more effective at detecting recurrence than minimal symptom-based follow-up. However, the combination of the two modalities was not more effective than either alone, in the randomized Follow-up after Colorectal Surgery (FACS) trial.2

David Mant, MD, of Oxford University, noted that patients with colorectal cancer experience anxiety surrounding disease monitoring, and economic modeling has suggested that intensive follow-up may not be cost-effective. “Intensive follow-up seems like a bad idea unless there’s a clear benefit,” he commented. “We did a trial to assess that benefit.”

The study included 1,202 patients who underwent curative treatment for primary colorectal cancer and had no residual disease. They were randomized to one of four follow-up regimens: minimal follow-up (primary care, symptom-based, involving a single CT scan at 12–18 months), or follow-up primarily by CEA monitoring (CEA every 3 months for 2 years, then every 6 months in years 3 to 4, with a single CT scan at 12 to 18 months), or primarily by CT (CT every 6 months for 2 years, then annually for another 3 years), or CEA plus CT (CEA as in the CEA follow-up group plus CT as in the CT follow-up group).

The outcome was defined as the proportion of patients with recurrence treated surgically with curative intent. Altogether, this occurred in 6% of patients, which was lower than expected, probably because patients were “rigorously staged” up front, he said. By surveillance arm, the proportion was 2.3% among patients with minimal follow-up, 6.7% of those followed by CEA, 8.0% of patients followed by CT scan, and 6.6% followed by CEA plus CT. There were no differences by disease stage.

“About 1 in 14 participants in the three intensive follow-up arms had recurrences that could be treated surgically with curative intent. We saw about a 4% difference for minimal follow-up vs the other arms, and no additive benefit for CEA plus CT, vs either alone,” he reported.

At time of analysis, 59% of patients with recurrence treated surgically with curative intent were alive, with no difference between the arms.

Tim Maughan, MD, Professor of Clinical Oncology at Oxford University, discussed the study after its presentation emphasizing that while minimal follow-up was less effective, there was no difference between the three intensive protocols. “This challenges our current practice of repeated CT scans,” he said. After 3 years, few recurrences (1%–2%) were detected, he added.

“The FACS trial showed that clinical appointments add nothing to the detection of resectable recurrence, and multiple CT scans add nothing over a single CT scan with regular CEA measurements—only the risk of radiation-induced malignancy. The study also suggests that the benefit of follow-up is similar across stages I to III, and this could change our practice.”

No Benefit for Routine Imaging in Hodgkin Lymphoma

No benefit was observed for routine surveillance imaging over clinical surveillance for monitoring classical Hodgkin lymphoma patients for relapse, in a multicenter study reported by Sai Ravi Pingali, MD, of the Medical College of Wisconsin in Milwaukee.3

“We were unable to detect an overall survival benefit associated with routine surveillance imaging, although the power is limited by the small number of deaths and relapses. Relapses in both clinical surveillance and routine surveillance imaging groups were effectively salvaged with autologous stem cell transplant. The costs associated with routine surveillance imaging are significant, and the potential risks from routine surveillance imaging must also be considered,” Dr. Pingali said.

The study included 241 Hodgkin lymphoma patients achieving complete remission between 2000 and 2010 and followed for at least 2 years with routine surveillance imaging (n = 164) or clinical surveillance (n = 77). With routine surveillance imaging, the intended plan of surveillance was radiologic imaging, clinical exam, and labs; the clinical surveillance group underwent clinical exams and labs, with radiologic tests to evaluate concerning signs and symptoms.

At 8 years, no overall survival differences were observed (P = .47). At 5 years, when scans are typically discontinued, more than 95% of each group was alive and the curves were essentially superimposable. The type of chemotherapy and receipt of consolidation radiotherapy (which did differ at baseline) did not affect survival. There were five deaths in the routine surveillance imaging group, only one attributed to relapse. In the clinical surveillance group six patients died, none from Hodgkin lymphoma. All relapsed patients were successfully retreated.

Mean number of scans was 1.14 in the clinical surveillance group and 4.25 in the routine surveillance imaging group. To detect one relapse required 18 scans and 124 scans, respectively. The cost per relapse was nearly $19,000 more with routine surveillance imaging surveillance, not including the costs associated with false-positives.

Routine CT Scans in Diffuse Large B-cell Lymphoma

A multicenter cohort of 644 patients newly diagnosed with diffuse large B-cell lymphoma showed that CT scans, typically a routine part of follow-up after treatment, may be unnecessary. For the vast majority of patients, relapses were detected based on symptoms, abnormal blood tests, or abnormal findings on physical exam, reported Carrie A. Thompson, MD, of the Mayo Clinic, Rochester, Minnesota. Only 1.5% of patients in remission had a relapse that was detected solely through a scheduled imaging scan.4

Disclosure: Dr. Maughan is a consultant or advisor for Sanofi and has received research funding from Merck Serono. Drs. Simos, Mant, Pingali, and Thompson reported no potential conflicts of interest.

References

1. Simos D, Hutton B, et al: 2013 ASCO Annual Meeting. Abstract 6597. Presented June 3, 2013.

2. Mant D, Perera R, et al: Effect of 3-5 years of scheduled CEA and CT follow-up to detect recurrence of colorectal cancer. 2013 ASCO Annual Meeting. Abstract 3500. Presented June 1, 2013.

3. Pingali SR, Jewell S, et al: Clinical or survival benefit to routine surveillance imaging for classical Hodgkin lymphoma patients in first complete remission. 2013 ASCO Annual Meeting. Abstract 8505. Presented June 1, 2013.

4. Thompson CA, Maurer MJ, et al: Utility of post-therapy surveillance scans in DLBCL. 2013 ASCO Annual Meeting. Abstract 8504. Presented June 1, 2013.



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