Hello I am a student in Cairo university.

Sherif, you can apply for an S2 type for the treatment in Beijing.
The supporting documents include your passport and its copy, the application form, a recently-taken passport-style photo, an invitation letter from Beijing international hospital or copy of the diagnosis certificate, an introduction letter from the ministry of foreign affairs, flight itinerary and bank savings account.

Is this introduction letter from the foreign affairs ministry mandatory? Because it will take time and my appointment will be held after 5 days. I have all my medical reports. Is still required to have this letter because it may take some time and unfortunately my time is too tight.

Sherif, I think this letter is mandatory, anyway the consular officer has the final say. You can go to the embassy to get a confirmed answer.

Can they provide me a visa type with at least 6 months for treatment with multiple enteries?

I'm afraid not.

So what kind will they provide me? How long is it? And can I extend it later in China?