Source: Elsevier Global Medical News. 2012 Feb 23, D McNamara

MIAMI BEACH (EGMN) – Using PET scans to diagnose distant metastasis in patients with advanced head and neck squamous cell carcinoma does not significantly prolong life expectancy, compared with other imaging techniques, according to a retrospective study.

Palliative chemotherapy did make a difference, however, significantly increasing life expectancy by 215 days in patients who received it, Dr. Matthew E. Spector and colleagues from the University of Michigan, Ann Arbor, reported at a meeting of the Triological Society.

“Over 90% of patients at University of Michigan have at least one PET scan at some point in their treatment,” Dr. Spector said. Increased sensitivity is one reason for such widespread adoption of the imaging technique. “We were wondering, while it may be more sensitive to identify distant metastatic disease, was it changing what we were doing?”

In a retrospective look at 170 patients with such cancers at their institution, researchers found no significant difference in median survival between patients who had a PET scan (168 days) and those who did not (193 days). Determination of any survival difference was a primary aim of the study.

“A lot of studies have looked at PET scans, and we know in up to one-third of cases it may change our decisions,” Dr. Spector said. For example, a negative PET scan might mean definitive treatment, whereas a positive PET finding might lead to palliative therapy. However, “no one has looked at the impact of the PET findings on the life expectancy after diagnosis.”

All patients in the study had a distant metastasis diagnosis. “We found PET was more likely to diagnose multiple distant metastasis sites [P = .03],” Dr. Spector said. “But there were no differences in life expectancy when comparing PET to the various other imaging modalities like CT or chest x-ray.”

Mean patient age was 59 years, and 135 of the patients were men. Kaplan-Meier survival curves revealed no difference in survival between patients with a single distant metastatic site vs. multiple distant metastatic sites, said Dr. Spector, a head and neck surgery resident at the University of Michigan Health System in Ann Arbor.

The investigators intentionally controlled for chemotherapy use (110 patients, or 65%) in their survival calculations. “Chemotherapy could alter the course of their distant metastasis. Since [survival] was our main outcome measure, we wanted to control for that.”

There were no differences in survival by patient age, sex, or site of primary tumor. Primary head and neck tumor sites included the oropharynx in 75 patients, the oral cavity in 40 patients, and the larynx in 36 others. The hypopharynx, nasopharynx, and some cases with unknown primary sites accounted for the remainder.

Dr. Spector and his associates did find a significant difference between the 86% of patients whose distant metastasis was detected during routine follow-up cancer care and the 14% who presented with symptoms. Median survival was 247 days in the routine surveillance group vs. 73 days for patients who might have come into the clinic complaining of chest pain after which subsequent imaging studies revealed a distant metastasis.

“Patients who were symptomatic, as you would imagine, had a worse life expectancy,” Dr. Spector said. For the group detected on routine follow-up, the median time to distant metastasis diagnosis was 324 days.

Identification of any factors that did prolong survival was a second aim of the study. For the 85 patients who received palliative chemotherapy, median survival was significantly longer at 285 days, compared with 70 days for those who did not receive it. Palliative chemotherapy was an independent factor that increased life expectancy, “and should be promoted for patients with these cancers,”

Dr. Spector said at the meeting, which was sponsored by the Triological Society and the American College of Surgeons. Previous chemotherapy did not alter patient response to palliative chemotherapy.”Even for patients who were symptomatic at the time of diagnosis of their distant metastasis, palliative chemotherapy was still found to be effective,” he added.

By cancer subtype, there was a nonsignificant trend for palliative chemotherapy to prolong survival among patients with primary oropharyngeal cancers (median, 333 days) compared with patients with primary laryngeal cancers (195 days).

Dr. Spector said that he had no relevant disclosures.

This news story was resourced by the Oral Cancer Foundation, and vetted for appropriateness and accuracy.

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