Afterwards she was diagnosed with breast cancer; lots of swelling in the arm; had lots of fatigue; This is a spontaneous report from a contactable physician (Patient). A 62-years-old female patient received bnt162b2 (BNT162B2, solution for injection; Batch/Lot Number: EK9231), dose 2 via an unspecified route of administration on 05Jan2021 as dose 2, single (At the age of 62-years-old) for covid-19 immunisation. The patient medical history and concomitant medications were not reported. Historical vaccine included received first dose of BNT162B2 (COMIRNATY, solution for injection, Batch/Lot Number: EK5730), via an unspecified route of administration, administered in Arm Left on 17Dec2020 (at the age of 62-years-old) as single for COVID-19 immunization. No Prior Vaccinations (4 weeks Prior) was received. Family Medical History relevant to AE was reported as No. On an unspecified date the patient was diagnosed with breast cancer and lots of swelling in the arm and Lymphedema. She went through breast surgery, radiation. She was on a shorter course in July that ended in august then she went in for her booster dose of the Pfizer covid vaccine on 21Aug2021. She got swelling like her first time and it lingered and got lymphedema. After the 2nd dose of the Pfizer covid vaccine she had lots of fatigue and lots of swelling in the arm. Caller was wondering if it was properly effective. She got the injection on the same side as the surgery. She got lymphedema on that side. Is the vaccine effective. She is a physician who treats patients (who may or may not have COVID). She was concerned about the booster dose not being effective due to lymphedema. Consumer (Physician) stated she took the Pfizer Vaccine, when they first came out in December. Her second injection was in the first week of January. Time of vaccination was Probably about the noon on the second. She mean noon on the 21st. She got the booster but in between all of that time, She got the Breast Cancer Diagnosis, have to have a mass removed surgery (Further clarification unknown) and then they did what is it called a Sentinal node biopsy (Not clarified) and this is on the left side. She had no Lymphedema post-surgery at all and then she got the injection on that left side, okay and then this is on the 21Aug2021 and her arm been swelled up with pretty significant Lymphedema. It's just starting to go away. Her question is, is the vaccine still effective for me? Been that she got a little Lymphedema after the vaccine and they took she would say almost 3 weeks to start to go down. It is just starting to get less and less and less through time but all of my concern is specially being a Physician who could possibly, as an Anesthesiologist (Not clarified) always be exposed to the possibility of the patient with COVID. The first one was at a Hospital. (Hospital Name) and that was for the first and second dose. In fact the third one was at the (Facility Name). Laboratory Test was reported as None. Therapeutic measures were taken as a result of afterwards she was diagnosed with breast cancer. Consumer stated, During this period of time, well she had Radiation (Not clarified). Removal of that, she had Radiation after that finished on, it finished on 02Aug2021 and on the 01Sep2021 she have started the Arimidex (Further clarification Unknown hence not captured in tab) the chemotherapeutic walker and she started that on 01Sep2021. Consumer stated, No she actually she didn't wanna treat with anything so she didn't take Tylenol, she didn't take anything. The outcome of the events was unknown.   No follow-up attempts are Possible. No further information is expected.; Sender's Comments: Based on available information the reported event breast cancer cannot be totally excluded/assessed. Case will be reassessed when the new information available. The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to RAs, Ethics Committees, and Investigators, as appropriate.