The high incidence of cancer associated with organ transplants is probably related to the drugs administered to such patients, an assistant professor at the Medical School said yesterday.

Dr. Martin S. Hirsch, a specialist in infectious diseases, said that lymphomas--tumors of the lymph glands--occur "several thousand times" more often among transplant patients than among healthy people of the same age groups. The studies revealing this fact were conducted at the University of Colorado Medical School and the Veterans Administration Hospital in Denver, he said.

Although the figures sound high, Dr. Hirsch called the actual incidence of these tumors "proportionately rare." "Only 100 primary tumors have been reported out of the total of 10,000 transplants performed in the entire world in the past ten years," he said.

Hirsch, who based his conclusions on recent research he has done on laboratory animals, said that the tumors are probably caused primarily by the drugs administered to transplant patients to prevent the grafted organs from being rejected by the body.

The body's immunity system tries to expel or destroy all foreign matter, Hirsch explained. "The immunity system is depressed intentionally by the drug to prevent rejection of the transplanted organ," he added.

If a viral infection, which current medical theory holds to be a main cause of cancer, should occur, the body would not be able to reject either the virus or the tumor, he said.

Immune-suppressing drugs are not the only causes of cancer in transplant patients. "The graft-rejection response itself can activate from a latent state a virus capable of causing tumors," Hirsch said.

The goal of Hirsch's research is to devise a method that will "trick the immune system to accept a graft without using drugs." Doctors are now attempting to combat the problem by tissue-typing, he said.