BUFFALO — Supreme Court Justice Ruth Bader Ginsburg on Monday made her first public appearance since completing radiation treatment for her latest bout with cancer, saying it was “both a joy and a sorrow” to appear at an event organized by a college friend who died late last year.

The 86-year-old justice received an honorary degree in the morning and regaled a packed performing arts hall in the evening.

She was invited last year by Wayne D. Wisbaum, a friend from her undergraduate days at Cornell. Wisbaum died in December, but not before making sure Ginsburg could still attend the event, which included an honorary degree at the University at Buffalo law school.

“When I promised I would come, I did not know that this day would be preceded by three weeks of radiation,” she said.

Ginsburg was escorted across the stage at the Kleinhans Music Hall on Monday night and earlier in the day at the university. But she spoke with a clear, strong voice at both events about her pioneering career, her friendship with retired Justice Sandra Day O’Connor and her late-in-life fame as “the Notorious R.B.G.”

“I am now 86 years old, yet people of all ages want to take their picture with me. Amazing,” Ginsburg said at the morning event.

If she is notorious, Ginsburg continued, “it is because I had the good fortune to be alive and a lawyer” in the 1960s and ’70s. That is when “it became possible to urge before courts, successfully, that equal justice under law required all arms of government to regard women as persons equal in stature to men.”

In her conversation with Aviva Abramovsky, the first female dean of the University at Buffalo’s law school, Ginsburg said proposals to increase the number of Supreme Court justices are “a very bad idea.”

As she often does, Ginsburg lamented the absence of “a true bipartisan spirit in Congress” when it comes to judicial nominations.

“I hope one day there will be people who care about our country — both Democrats and Republicans — who will come together and say enough of this dysfunctional legislature,” Ginsburg said.

Ginsburg’s visit drew more attention than most because of the recent disclosure of her latest medical problems.

It was the second treatment for cancer in nine months for the court’s oldest member and leader of its liberal wing. Ginsburg had a lobe of her left lung removed in December, and in the past was treated for colon and pancreatic cancer.

The court said the three-week treatment for her current condition began this month at Memorial Sloan Kettering Cancer Center in New York, and no additional treatment is planned.

“The tumor was treated definitively and there is no evidence of disease elsewhere in the body,” the court’s spokeswoman said in a statement. “Justice Ginsburg will continue to have periodic blood tests and scans. No further treatment is needed at this time.”

Ginsburg is one of the oldest justices to serve on the Supreme Court, and her health is a constant matter of concern and speculation. Her inability to serve would provide President Trump with a chance to nominate a third conservative to the high court and shift it further to the right.

Ginsburg said in speeches and in an interview last month that her health was fine, and she would continue to serve as long as she felt up to the job.

During her treatment, Ginsburg took in a couple of shows in New York. She is scheduled to appear at the National Book Festival later this week, and give a lecture in Arkansas next week.

Barnes reported from Washington.