With new urgency and new hopes, three families of Soviet Jews seeking permission to emigrate appealed today for help in getting medical treatment abroad for relatives stricken by cancer.

"We especially want to appeal to the people of the world to pay attention to our desperate situation," said Naum Meiman, 75, a human rights activist whose wife Inna Kitrosskaya suffers from cancer of the spine.

Kitrosskaya, 53, who has undergone four operations in the last three years and is now being treated with chemotherapy, has been invited abroad by several doctors. But she has been repeatedly denied even a temporary visa because of her marriage in 1981 to Meiman, a mathematician who did classified work 30 years ago.

"It is a killing, a murder in fact," said Meiman today.

Jewish emigration from the Soviet Union has slowed to a trickle since 1979 when it reached its peak of 51,000. Last year, about 1,000 people were given permission to leave.

Refuseniks, as those refused permission to emigrate are called, say tens of thousands have applied to leave. On Tuesday, the official Soviet news agency Tass scoffed at reports from Washington that 400,000 Jews are waiting to leave, saying that the figure is "overstated more than 100 times."

The small group of families of invalids gathered amid reports that new cases of refuseniks have been resolved favorably.

A Soviet official recently said permission has been given in 71 cases for Soviets to join family members in the United States. These case involve "more than 200" people, the official said.

So far, the full list of cases has not been disclosed here, although several well-known refuseniks have recently been allowed to leave. One, Boris Gulko, a former Soviet chess champion, left with his family after several public demonstrations.

For Meiman and the others, the new hopes come after years of waiting. Benjamin Bogomolny, 40, applied to leave the Soviet Union for Israel 20 years ago, making him the longest waiting refusenik.

Bogomolny's wife, Tatiana Kheifetz, underwent surgery for breast cancer seven months ago. She has been told that her request for a visa was refused because her husband had served in the Soviet Army, and his departure would be a security risk.

Benjamin Charny, 48, applied to emigrate to Israel in 1979 and shortly afterward was diagnosed as having melanoma. Like many other refuseniks, he and other members of his family lost their jobs.