my $pat = qr{Summary \w+\(\w\)};

while(<DATA>) {
    if (/$pat/ ... /$pat/) {
        next if /$pat/;
        print;
    }
}

__END__
gargantua
pantagruel
Summary 1000(1)
top
Date ....
Column1    Col2   Col3
bottom
Summary xxx(x)
foo
bar
baz