Is the word sutiã the same in Brazilian and European Portuguese?

Yes.

The spelling, meaning, and grammatical function of the word "sutiã" are identical in both Brazilian and Continental Portuguese. The only difference is in pronunciation: Brazilian Portuguese tends to pronounce the nasalized "ã" and the preceding "i" with more clarity and openness, whereas Continental Portuguese often features more significant vowel reduction, which can make the unstressed syllables sound more closed or nearly swallowed.

Brazilian Portuguese

1. Eu comprei um sutiã novo ontem. (I bought a new bra yesterday.)
2. Esse sutiã está muito apertado. (This bra is very tight.)
3. Ela não gosta de usar sutiã. (She doesn't like to wear a bra.)
4. Onde posso encontrar sutiãs de renda? (Where can I find lace bras?)
5. Você viu o meu sutiã na gaveta? (Did you see my bra in the drawer?)

Continental Portuguese

1. Comprei um sutiã novo ontem. (I bought a new bra yesterday.)
2. Este sutiã está demasiado apertado. (This bra is too tight.)
3. Ela não gosta de usar sutiã. (She doesn't like to wear a bra.)
4. Onde é que posso encontrar sutiãs de renda? (Where can I find lace bras?)
5. Viste o meu sutiã na gaveta? (Did you see my bra in the drawer?)