Armstrong, speaking on a telephone conference call from an Anaheim, California, cycling trade show, said his decision stemmed from good news he received during a doctor's visit last week in Indianapolis.
``They were extremely optimistic, and I'd never seen that from them before,'' Armstrong said. ``Before, they were hesitant and cautious what they said to me.''
Armstrong's cancerous testicle was removed Oct. 3, the day after diagnosis. Soon it was discovered that the disease had spread to his lungs, stomach and brain. Chemotherapy and brain surgery followed.
Doctors told him the chances of future surgery were ``almost zero'' and death is almost ``totally out of the picture,'' said Armstrong, who lives in Austin, Texas.
Last week's news wasn't all good. Cofidis, the French cycling team, told Armstrong it would not exercise the second year of a two-year contract, forcing him to seek another team.
His agent, Bill Stapleton, said they have a 4-6-week window in which to find a new team. Armstrong said he hasn't had the chance to seriously discuss contracts yet.
Stapleton and Armstrong ``haven't even thought'' about what they'd do if a team can't be found, Stapleton said. Armstrong did say he probably wouldn't consider riding U.S. races.
"I consider myself part of the European (cycling community),'' he said. ``That's what I want to return to.''
October or November in preparation for the spring season, he said. He's riding about two hours a day now.
``I didn't just take a year off. It's a year in which physically I went through a lot of hard stuff,'' he said. ``Tests indicate nothing has changed for me physically. So, it's just a question of how much did I lose by taking a year off?''
He described himself as ``very curious'' about how well he'd be able to ride in 1998.
1935: Gustaaf Deloor, Belgium 1936: Gustaaf Deloor, Belgium 1941: Julian Berrendero, Spain 1942: Julian Berrendero, Spain 1945: Delio Rodriguez, Spain 1946: Dalmacio Langarica, Spain 1947: Edouard Van Dyck, Belgium 1948: Bernardo Ruiz, Spain 1950: Emilio Rodriguez, Spain 1955: Jean Dotto, France 1956: Angelo Conterno, Italy 1957: Jesus Lorono, Spain 1958: Jean Stablinski, France 1959: Antonio Suarez, Spain 1960: Franz Demulder, Belgium 1961: Angelino Soler, Spain 1962: Rudi Altig, West Germany 1963: Jacques Anquetil, France 1964: Raymond Poulidor, France 1965: Rolf Wolsfsohl, West Germany 1966: Francisco Gabica, Spain 1967: Jan Janssen, Netherlands 1968: Felice Gimondi, Italy 1969: Roger Pingeon, France 1970: Luis Ocana, Spain 1971: Fernando Bracke, Belgium 1972: Jose Manuel Fuente, Spain 1973: Eddy Merckx, Belgium 1974: Jose Manuel Fuente, Spain 1975: Agustin Tamames, Spain 1976: Jose Pesarrodona, Spain 1977: Freddy Maertens, Belgium 1978: Bernard Hinault, France 1979: Joop Zoetemelk, Netherlands 1980: Faustino Ruperez, Spain 1981: Giovanni Battaglin, Italy 1982: Marino Lejarreta, Spain 1983: Bernard Hinault, France 1984: Eric Caritoux, France 1985: Pedro Delgado, Spain 1986: Alvaro Pino, Spain 1987: Luis Herrera, Colombia 1988: Sean Kelly, Ireland 1989: Pedro Delgado, Spain 1990: Marco Giovanneti, Italy 1991: Melchor Mauri, Spain 1992: Tony Rominger, Switzerland 1993: Tony Rominger, Switzerland 1994: Tony Rominger, Switzerland 1995: Laurent Jalabert, France 1996: Alex Zulle, Switzerland race not held 1937-40, 1943-44, 1949, 1951-54
The 3,762 km trek starts on Saturday, away from home for the first time in its 52 years, and Jalabert claims he is no more than a "strong contender".
The Frenchman beat 1995 world road race champion Olano by four minutes and 22 seconds in the 1995 Vuelta.
"When I beat Olano in the Vuelta I had come to the race totally relaxed because I was not supposed to be a contender. Now I am in the same state of mind, and I don't want to put pressure on myself," Jalabert explained.
"I had too much pressure in the Tour de France, and it was catastrophic. Because of that I am motivated for the Vuelta."
Jalabert has a penchant for the Spanish race. As well as overall victory in 1995, he has won 16 stages over the past four years, and last year completed a hat-trick as top points-scorer.
He also topped the mountain standings two years ago, and that coupled with his strong finishing underlines his pedigree for this race.
Olano is expected to head any Spanish drive to wipe out last year's memories. Then, for the first time, Spain failed to figure in the top five or win any of the other four prize categories.
Along with his runner-up spot in the 1995 Vuelta, Olano was third in the Giro d'Italia last year, and more impressively finished fourth in July's Tour de France.
His strength is in races against the clock, and Jalabert said: "Considering the Vuelta's two time trials I am not the favourite. It could mean that I will have to attack day after day to gain time."
The first of the two time trials is not until day nine in Cordoba, and the second at Alcobendas comes on the eve of the Madrid finale (Sept 28) to the 22-day race.
Jalabert's team includes previous Vuelta winners, Spain's Melchor Mauri (1991) and Alex Zuelle from last year.
Zuelle gave Switzerland their fourth triumph in five years with a record average speed of 40.470 kph. This time he has a support role, because, according to their team manager Manolo Saiz, Zuelle is "overweight and out of shape."
This is a knock-on from fracturing his collarbone in the Tour de Suisse and 10 days later contesting the Tour de France, a quest that ended in the first week.
The Swiss particularly have been a bane to Spanish hopes. Last year they filled the first three spots with Zuelle, Laurent Dufaux, and Tony Rominger.
Lacking form after fracturing a collarbone in the Tour de France, Rominger arrived in Portugal with little chance of making much progress in the race that three years ago he became the first to capture three times.
Among the Big Three tours in cycling the Vuelta is a late-comer to frontier-crossing.
Now it has followed the trend set by the Tour de France which has opened in Spain, Belgium, Netherlands, Switzerland, and Germany. The Giro d'Italia started in Belgium in 1973, and last year went to Greece.
The first day (Saturday) takes the 198 riders over a 155.7 km route to finish on Estoril autodrome, home of the Portugese Grand Prix.
After three days of racing in Portugal the Vuelta heads for the Spanish resorts of the Costa del Sol and on to its first climbing test in the Sierra Nevada.