NEW YORK — Diane Benson, 53, had always adored the family dog, Pepper, a black Labrador who would excitedly greet her on the driveway when she came home. But their bond grew particularly strong after her kids grew up and moved away.

"Some people say they can't wait to be an empty nester, but this dog filled a void for me," said Benson, a high school Spanish teacher in Potomac, Md.

Recently, Pepper died of cancer. Now, Benson and her husband have Lucky, a new lab. This time around, Benson says she would strongly consider cancer treatment, regardless of cost, if Lucky was stricken and there was a good chance of success.

"I took Pepper's death very hard," she said.

Fed by a growing bond between owners and their pets, companies are ramping up their offerings of pet care and luxury services ranging from cancer and arthritis treatments to cat and doggie massages, acupuncture and room service.

Analysts say much of the demand is being driven by more affluent baby boomers, born between 1946 and 1964, whose children recently moved away but who don't yet have grandkids to indulge.

"An empty nest is a pet's best friend," said Ken Budd, features editor at AARP The Magazine. "Boomers are more inclined to spoil pets. Just as their kids had to go to the best camp, the dog or cat has to have the best toy, the latest gadget."

The average age of a pet owner is now 46. They contribute to a $31 billion pet care industry, according to the American Pet Products Manufacturers Association.

A recent report by the Mc-Kinsey Group predicts that the pet care industry will grow 4.5 percent annually to reach about $36 billion by 2007. It cited strong potential in basic pet medications, such as those that stave off parasites; treatment of age-related diseases including arthritis, kidney problems and cancer; and products for "lifestyle issues" such as reproduction control and anti-obesity drugs.

Companies are already responding.

Addison Biological Laboratory Inc., for example, recently began offering a sterilization shot for puppies, called Neutersol, to replace surgical castration, while Pfizer Inc. developed a new arthritis pill for dogs in 1997 that comes in a tasty chewable liver flavor.

The goal: make medical treatments not only more effective but also less painful for pets, allowing doting owners to have greater peace of mind.

"We get calls from consumers who say, 'Geez, my dog has cancer, diabetes, this problem or that, is there something we can do?' " said Bob Fauteux, a spokesman at Pfizer Animal Health. "We are indeed very actively trying to address these problems."