CHICAGO — When emergency tests showed the telltale right-sided pain in Heather VanDusen’s abdomen was appendicitis, she figured she’d be quickly wheeled into surgery. But doctors offered her the option of antibiotics instead.

A new study from Finland shows her choice is a reasonable alternative for most patients with appendicitis. Five years after treatment with antibiotics, almost two-thirds of patients hadn’t had another attack.

Dr. Linda Vorvick examines Heather VanDusen in Arlington, Wash. VanDusen was given antibiotics to treat her appendicitis and a new study shows it's a reasonable alternative treatment to surgery. Clare McLean/UW Medicine via AP

It’s a substantial change in thinking about how to treat an inflamed appendix. For decades, appendicitis has been considered a medical emergency requiring immediate surgery to remove the appendix because of fears it could burst, which can be life-threatening.

But advances in imaging tests, mainly CT scans, have made it easier to determine if an appendix might burst, or if patients could be safely treated without surgery.

The results suggest that nearly two-thirds of appendicitis patients don’t face that risk and may be good candidates for antibiotics instead.

“It’s a feasible, viable and a safe option,” said Dr. Paulina Salminen, the study’s lead author and a surgeon at Turku University Hospital in Finland.

Her study in adults is the longest follow-up to date of patients treated with drugs instead of surgery for appendicitis and the results confirm one-year findings reported three years ago.

Research has also shown antibiotics may work for some children with appendicitis.

Appendix removal is the most common emergency surgery worldwide, with about 300,000 performed each year in the United States alone, said Salminen. She said the results from her study suggest many of those surgeries could be avoided.

U.S. doctors have started offering antibiotics instead of surgery and Salminen says she occasionally does too. The journal editorial says appropriate patients should be given that option.

The study involved about 500 Finnish adults who had CT scans to rule out severe cases.

Half were treated with antibiotics; the others had surgery.

Among the antibiotics patients, 100 ended up having surgery within five years of treatment — most for a suspected recurrence of appendicitis in the first year. Seven of them did not have appendicitis and likely could have avoided surgery. The results suggest the success rate for antibiotic treatment was almost 64 percent, the authors said.