Local excision margins larger than 1.0 cm associated with improvements in overall survival

A study into the association between local excision (LE) margins and overall survival (OS) in patients with Merkel cell carcinoma has identified a link between larger surgical margins and improvements in OS. 

The large, multicentre retrospective cohort study – published in JAMA Dermatology – used National Cancer Database records to identify patients with localised stage I or stage II Merkel cell carcinoma, who underwent LE between 1 January 2004 and 31 December 2015  

Five years after surgery, LE margins of 1.0 cm or smaller were associated with a net survival of 76.7%, while LE margins larger than 1.0 cm were linked with a net survival of 89.8%  

Further stratification of LE margins, which were divided into three subgroups, found that LE margins of 1.1 to 2.0 cm were associated with improvements in OS compared with those measuring 1.0 cm and smaller. 

For patients who received adjuvant radiotherapy, larger LE margins were also associated with improvements in OS.  

Patients who received adjuvant radiotherapy with LE margins of 1.0 cm or smaller experienced a comparable OS to that of patients who did not receive adjuvant radiotherapy but who had LE margins larger than 1.0 cm.  

Improvements in OS were also observed in patients with less aggressive disease and who had LE margins larger than 1.0 cm – this included patients who were immunocompetent and had tumours =1.0 cm, no lymphovascular invasion and negative pathologic margins. 

“This study’s analysis of retrospective data indicated that local excision with clinical operative margins larger than 1 cm and adjuvant radiotherapy are preferable treatments when feasible,” commented the researchers.  

“The combination of LE clinical margins larger than 1.0 cm and adjuvant radiotherapy was associated with the highest OS,” they added.