Police said Tuesday the charges resulting from the investigation of Santa Rita Clinic ranged from fraud to homicide.
Three of the doctors were arrested on suspicion of murder for allegedly having performed on several patients "abnormal or invasive surgeries, without taking into consideration the fragility of the patients because of age or their medical condition," the police statement said.
Police officials said five patients at the clinic are believed to have died after suspected needless surgeries. A hospital official was also arrested, police said.
Repeated calls to the clinic Tuesday afternoon went unanswered.
One man who said he was a patient told Italian state TV that he was given a lung operation instead of thyroid surgery.
"When I awoke, I found these tubes under my armpit," Giovanni Rizzitano said, pointing to his side as he was interviewed on state TV Tuesday. "They had operated on my lung."
The head of thoracic surgery was among those reported arrested.
La Repubblica, a Rome daily, quoted Riziero Scocchetti, the 72-year-old brother of Maria Luisa Scocchetti, who died shortly after lung surgery in 2006 at Santa Rita. The woman, 65, was dying of breast cancer in the hospital, the brother was quoted as saying.
"I asked the doctors to let her die in peace," Scocchetti said, according to the newspaper. "They reassured me that they were doing everything to save her. Instead they operated on her lung. But everybody knew she wasn't going to make it."
The newspaper quoted former patient Alfredo Scordo, 76, as saying part of his lung and some lymph nodes were removed in 2005 while he was recovering from pneumonia in the hospital.
"They cut open my back, four hours under the knife for a long and painful surgery," Scordo was quoted as saying.
Police contend that the clinic doctored patients' charts so it could obtain higher reimbursement for the costlier surgeries from the Italian national and regional health service in 2005 and 2006, for a total, police allege, of some US$3.8 million in extra money.
Italian news reports carried what were said to be transcripts of wiretaps in which doctors sound eager to do expensive surgeries. In one wiretapped conversation, a doctor reportedly cursed when told that a 90-year-old patient had been rejected for lung surgery because of breathing difficulties.