Breast Cancer; Breast Cancer; lymphedema; My arm been swelled up; This is a spontaneous report from a contactable physician (patient herself). A 62-years-old female patient received BNT162B2 (PFIZER BIONTECH COVID-19 mRNA VACCINE, Solution for injection, Lot Number: FC3183) via an unspecified route of administration in left arm on 21Aug2021 (reported as noon on the 21st) as dose 3, single (at the age of 62 years old) for COVID-19 immunization. Patient medical history included Breast surgery, Radiation therapy, left breast cancer.  The concomitant therapy includes patient had Radiation, it finished on 02Aug and on the 01Sep started the Arimidex the chemotherapeutic walker. The patient experienced breast cancer, lymphedema, arm been swelled up on an unspecified date. Patient wanted to know if the booster dose was less effective due to, side effect of lymphedema and if patient needed to get another booster dose on the other arm. No family medical history relevant to AE was reported. Historical vaccines included BNT162b2 (PFIZER BIONTECH COVID-19 mRNA VACCINE,, Solution for injection, Lot number- EK5730) via an unspecified route of administration in left arm on 17Dec2020 as dose 1, single (at the age of 62-years-old) and received BNT162b2 (PFIZER BIONTECH COVID-19 mRNA VACCINE, Solution for injection, Lot number- EK9231) via an unspecified route of administration in left arm on 05Jan2021 as dose 2, single (at the age of 62-years-old) both for COVID-19 immunization. Patient got swelling like her first time and it lingered and got lymphedema after the first dose and had lots of fatigue and lots of swelling in the arm after the second dose of vaccination. It was reported that 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 is concerned about the booster dose not being effective due to lymphedema and if so should she get another booster dose on the other side of the arm. Is there less clearance because of the edema formed. "Because of the side effect of lymphedema do I have adequate immunity." I got the booster but in between all of that time, I 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. I had no Lymphedema post-surgery at all and then I got the injection on that left side, okay and then this is on 21Aug2021 and my arm been swelled up with pretty significant Lymphedema. It's just starting to go away. My question is, is the vaccine still effective for me. Been that I got a little Lymphedema after the vaccine and they took I 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. Is that booster effective? Not knowing how, yeah the 'other' vaccine you know sort of works until this is a question that I am having right now." Consumer stated, "During this period of time, well I had Radiation (Not clarified). I have breast Cancer. Removal of that, I had Radiation after that finished on, it finished on 02Aug and on the 01Sep I have started the Arimidex (Further clarification Unknown hence not captured in tab) the chemotherapeutic walker and I started that on 01Sep." Consumer stated, "No I actually I didn't wanna treat with anything so I didn't take Tylenol, I didn't take anything." Vaccination facility type was reported as Health centre for the first and second dose and third one was at the Pharmacy. Patient did not receive any other vaccine in four weeks. The clinical outcome of the breast cancer, lymphedema, arm been swelled up was unknown.  Follow-up (06Sep2021): This is a follow up spontaneous report from a contactable Physician. This Physician (patient) reported that: clinical information merged and updated with the initial narrative.  No follow-up attempts are possible. No further information is expected.; Sender's Comments: Based on the information currently available, a possible contributory role of the suspect vaccine BNT162B2 or comirnarty in triggering the onset of breast cancer cannot be excluded.But also consider patient had relevant medical history of breast cancer and breast surgery present.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 Regulatory Authorities, Ethics Committees and Investigators, as appropriate.