What was going on when I was born?

Surgery that spares most of the breast can be as effective as radical mastectomy in treating women with early breast cancer, according to a major study done in Italy and published yesterday in The New England Journal of Medicine. The study, considered the best to date examining two such procedures, has thus far shown no difference in cancer recurrence or survival between women who had a partial mastectomy followed by radiation therapy and women who underwent the older, more disfiguring operation. Although previous studies suggested this, the new study is the only large-scale, well-controlled study to show it. The researchers concluded that ''radical mastectomy appears to involve unnecessary mutilation'' in patients with early breast cancer.

Garbage collection in northern and Central New Jersey was disrupted today after a teamsters local representing truck drivers struck an association of 35 privately owned refuse haulers. The walkout, which began late last night, was said to affect about 2.6 million people in 108 communities in 12 counties - Bergen, Essex, Hudson, Morris, Middlesex, Passaic, Union, Mercer, Monmouth, Ocean, Sussex and Burlington, where only one town was affected. The strike forced homeowners and the operators of restaurants, hospitals, factories and office buildings to scramble for safe ways to store potentially hazardous, perishable trash. In Elizabeth, Mayor Thomas Dunn declared a state of emergency and issued an order requiring all residents, industries and commercial establishments to separate food stuffs from such nonspoilable items as papers, cardboard and cans that can be stored without raising health risks. The perishable items, Mr. Dunn's office said, will be picked up by four city-owned compacting trucks once the trash has been declared a health hazard.

Israel's religious parties, crucial to the formation of the next government, indicated today that they would prefer entering a coalition with Prime Minister Menachem Begin's Likud bloc rather than with the Labor Party of Shimon Peres. As ballots still being counted from yesterday's elections continued to show a close race, Mr. Begin went into negotiations on such a coalition, with aides predicting an agreement next week. The Prime Minister met briefly with the head of the National Religious Party, Interior Minister Yosef Burg, who said that most of his members wanted a government headed by Mr. Begin. Rabbi Pinhas Menachem Alter, chairman of the other major religious party, Agudath Israel, was quoted by the Israeli press as calling any arrangement with Labor ''remote'' and expressing pride in having been part of the Begin Government for the last four years.

Patrick J. Cunningham, former Democratic chairman of New York State, was indicted in Manhattan yesterday on Federal charges of conspiracy, tax evasion, perjury and obstruction of justice. Mr. Cunningham, a 53-year-old lawyer who also served as the party's Bronx leader until 1978, remains a member of the Democratic National Committee. Denying the charges against him, he said he would be vindicated in a trial and would not resign his national committee post.

HUNDREDS of Manhattan apartment dwellers are waiting anxiously by their telephones this summer, some with suitcases already packed, for the call that may never come. They are actors and musicians with summer jobs on the road, teachers and analysts with summer vacations ahead, and the fortunate ones with second homes in the mountains, the Hamptons or the south of France. They are waiting for the attractive couple with excellent references to take loving care of their apartments and pay up to thousands of dollars for the privilege. But many wait in vain.

Mitterrand attacks U.S. policies on Central America A2 Reagan aides call strains with Haig ''a fact of life'' A3 Salvadoran leader says biggest threat is from businessmen A8 Government/Politics Agreement reached in Albany on penalties for drunken driving B2 Assembly approves withholding of bail in some cases B2 HOLIDAY WEEKEND Independence Day is Saturday. Most Federal and municipal offices will close tomorrow; New York State offices will be open. Following are holiday schedules: Parking - Alternate-side regulations suspended tomorrow and Saturday; all other rules in effect. Sanitation - Regular collections tomorrow. Collections normally made on Saturdays will be made Sunday. Federal Offices - Closed tomorrow and Saturday. State Offices - Open tomorrow. Courts - State, Federal and local courts closed tomorrow. Municipal Offices - Closed tomorrow. Post Offices - Open tomorrow, closed Saturday; only special delivery and express mail delivered Saturday. Banks - Open tomorrow. Stock and commodity markets -Closed tomorrow. Transportation - Buses and subways on regular schedule tomorrow; on Sunday schedule Saturday. L.I.R.R. and Conrail Harlem, Hudson and New Haven Divisions on regular schedule tomorrow; holiday schedule Saturday. Libraries - Closed tomorrow and Saturday.

Even on the steaming subterranean platforms of New York City's subway stations, humor dies hard. It may, in fact, be the ultimate test of humor to ask subway riders waiting in grimy stations for trains so crowded that they cannot board them how they feel about an increase in the fare tomorrow with a possible increase to follow two weeks from now. There were some extraordinary answers. ''I think it's nice,'' said the man in the blue shirt and the black hat. ''I think it's a nice luxury item for Carey and Koch,'' he explained. ''They'll be able to eat red snapper more often during the week.''

Because of an editing error, an arti- cle on the Chinese Communist Party's assessment of Mao Zedong yesterday incorrectly gave the dates of the eco- nomic development campaign known as the Great Leap Forward. It took place in 1958-59.

The Chinese Communist Party has published a platform of party goals that appeal to almost everyone except people opposed to continued Communist rule of China. The platform calls for slow but steady economic development and improvement of living standards, gradual extension of democracy under party control, a loose mix of public and private enterprise, a legal system that guarantees people's rights, a commitment to intellectual achievement, protection of religious freedom, a modernized army as the economy improves and more autonomy for ethnic minorities. At a rally in the Great Hall of the People today, the new party chairman, Hu Yaobang, said that China would stress the role of competent managers in a new era of orderly economic development and would no longer tolerate a single all-powerful ruler like Mao Zedong. (Page A12.)

The Dow Jones industrial average dropped 9.22 points, to 967.66, its seventh loss in eight trading sessions, as rising short-term interest rates deflated investor enthusiasm for stocks. Trading volume on the New York Stock Exchange rose to 49.1 million shares from Wednesday's 41.6 million. Conoco, a takeover candidate, rose 3 1/8 points as 1.4 million shares changed hands. (Page D1.) Prices declined and interest rates rose in all credit markets as dealers tried to trim inventory. (D7.) The dollar continued its surge against major foreign currencies. Gold and silver prices fell sharply in New York after appearing to stabilize earlier in European trading. Gold closed here at $415.50 a troy ounce, down $8.50 from Tuesday. (D11.)

Today was Canada's 114th birthday, and everyone of singing age was supposed to intone ''O Canada'' exactly at noon. It is doubtful that many did, for Canadians have always been diffident about displaying national fervor. They are even inclined to selfdeprecation and expressions of surprise when other people take notice of them. Lately, Canadians with money or the ability to raise it have been attracting notice to an unusual degree. In a country where much of the economy is dominated by outsiders and where the entrepreneurial class tends to be cautious and conservative (when it is not reduced to outright branch-plant management), individuals and companies of modest size by world standards have been displaying so much aggressiveness that they have sent American businessmen scurrying to Washington for help. Two Investment Trends There are two investment trends, somewhat contradictory in origin but both representing enough of a threat to rile United States business interests.

THE funny thing about Hoboken is that it has been discovered - over and over and over again. It's been almost 10 years since New Yorkers began to appreciate the charms of the mile-square city on the other side of the Hudson, but waves of newcomers continue to arrive. The town that has played host to immigrants from many countries is now being colonized by another kind of explorer, one in search of Victorian brownstones and brick row houses, cheaper rents and lower purchase prices than those to be found in Manhattan, and an atmosphere at once small town and big city. But the Hoboken renovators' refrain has changed little with the passing years. They love the 20-minute commute to New York City jobs and hate the jokes about Hoboken. Patricia and Tim Tuohy say they think they arrived at an ideal time, in 1975; Jeanine Palmer and Todd Nemanic, who came two years later, and Exilda and Robert Groux, who recently purchased a house, say they arrived at just the right time, too.