AT AHNS 2016

SEATTLE (FRONTLINE MEDICAL NEWS) – Additional resection to clear positive frozen tumor bed margins in oral cavity squamous cell carcinoma – a common practice in head and neck surgery – does not improve outcomes, investigators report.

In a retrospective review of 406 patients treated with oral cavity squamous cell carcinoma resection, the difference in local recurrence between patients with positive intraoperative frozen tumor bed margins cleared by additional resection (local recurrence in 27%) and those with positive frozen margins that were not cleared (local recurrence in 34%) was not statistically significant.

The team assessed local recurrence rates after dividing their review subjects – 61 years old on average and over half men – into those with negative tumor and tumor bed margins; patients with one positive and the other negative; and patients with both margins positive. Tumor beds were cleared to negative when possible.

The various configurations mattered for prognosis. Local recurrence ranged from 7% when both margins were negative to 65% when both were positive. Cancer recurred in 19% of patients with negative tumor but positive bed margins, and 35% of patients with positive tumor but negative bed margins. “Combining margin groups provides additional prognostic information, [but] the main specimen margin was the strongest predictor of recurrence. Positive margins on the main specimen carry a poor prognosis,” said lead investigator Marisa Buchakjian, MD , at the International Conference on Head and Neck Cancer, held by the American Head and Neck Society.

The study “should influence the use and interpretation of margin data in oral cavity squamous cell carcinoma surgery,” she said, since the majority of head and neck surgeons rely on tumor bed margins for prognosis, and consider positive tumor beds resected to clear pretty much the same as ones that are initially negative.

That approach is probably too simple. Intraoperative frozen tumor bed margins “were unreliable tests of main specimen margins, and would in fact be expected to miss approximately 50%” that are positive, said Dr. Buchakjian of University of Iowa Hospitals and Clinics, Iowa City.

She and her associates concluded that “the concordance between tumor bed and tumor specimen margins is not good … Cases of main specimen margin involvement with no corresponding findings in tumor bed frozen sections are common; conversely, frozen sections may show involvement, while the main specimen margins are negative. Prognostic information is contained within findings from both the frozen and specimen margins,” and neither should be considered the “true” margin. The tumor margin is an important predictor, even if margins are taken from the tumor bed.

However, “we do not believe that this provides evidence that a known positive margin should not be pursued with additional excision. We emphasize that this study highlights the prognostic importance of margin status and that an involved margin, either on the initial tumor bed frozen sections or the tumor specimen, is associated with worse outcomes regardless of the final margin result,” they said.

The authors had no conflicts of interest, and didn’t report external funding.