Begin's canceled trip: another hint of his possible retirement?

The cancellation for ''personal reasons'' of Prime Minister Menachem Begin's trip to Washington next week has renewed speculation here about the Israeli leader's health and his ability to keep up with the demands of office.

Mr. Begin's spokesman, Uri Porat, emphatically denied the cancellation was for health reasons.

But analysts here speculate that the cancellation stemmed from a combination of Mr. Begin's physical condition and a decision that the trip would not likely accomplish enough to be worth subjecting him to the strain.

The main purpose of the trip, coming on the heels of a visit by Lebanese President Amin Gemayel, would have been to discuss attempts to implement the Israel-Lebanon accord on withdrawal of Israeli troops from Lebanon. The trip also would have been a vindication for Mr. Begin; improved relations with the United States have dimmed the memory of President Reagan's previous unwillingness to receive him in the wake of US displeasure over the war in Lebanon.

But negotiations to carry out the Israel-Lebanon accord appear to have reached a dead end. The US has been unable to convince Syria to reverse its blockage of the accord by pulling its troops out of Lebanon. Moreover, the Americans appear to have reluctantly accepted the Israeli view that Israel must in the meantime implement a partial unilateral withdrawal from Lebanon in order to cut back on casualties.

These issues were all discussed during the recent visit of Secretary of State George Shultz to Jerusalem. There is not much new to say. The Israeli press has been speculating for more than a week that Mr. Begin might not go. Even had he gone, it would have been only for 48 hours - entirely unlike the formerly ebullient Begin, who in the past would have used the occasion to travel across the US, giving press interviews and rallying support from Jewish communities.

Mr. Begin's virtual retirement from public life over the past year has been the subject of increasing speculation among politicians and the Israeli media. He is known to be morose over the death last November of his wife, a constant companion for 42 years, and to be depressed by the impasse over withdrawal from Lebanon and continued Israeli casualties there.