Please clarify whether you were placed in the Private or Government Sector.
If in the Private Sector, please submit a detailed request letter with proper medical proof (Doctor's certificate/lab reports confirming the illness). The letter may be addressed to your Head of Department with a copy to HR. The content of the letter can be:
Dear Sir/Madam,
I would like to humbly present the following for your kind consideration. Very recently, I have been diagnosed with Papillary Thyroid Cancer with LN Mets Stage 3, and the copy of the Doctor's certificate/lab reports is attached herewith.
In light of the above, I hereby request you to transfer me from [current department name] to [new department name] as I will have to undergo [brief details about treatment]. I hope my request for transfer to [department name] will be considered on a humanitarian basis.
Thanking you,
Yours faithfully,
(Your Name)