Worldwide, breast cancer is the most common cancer among women, and its incidence and mortality rates are expected to increase significantly in the next years. It remains a major health problem. There is a vast area on breast cancer and immunity that still needs to be researched. Do anesthetic techniques and medication preferences effect immune responses? If so how they effect breast cancer outcomes is unclear.

On this trial, the investigators are searching anesthetic techniques affect on inflammatory and immune responses.

Breast cancer is the most frequently encountered surgery among all cancer surgeries. Although it is a well known procedure for anesthesiologists, it is still unclear whether anesthesiology effects immune responses. Cancer therapies often use immune therapies such as Bevacizumab (a monoclonal antibody which targets Vascular Endothelial Growth Factor), Trastuzumab(a monoclonal antibody for Herceptin (HER2/Neu) mutation) how anesthetics effect VEGF stays unclear.

Opioids are commonly used to provide analgesia for cancer pain, and functional opioid receptors have been identified on natural killer (NK) cells, the lymphocytes responsible for surveillance and elimination of cancer cells.[4] Anesthesiologists have well founded concerns about using morphine during cancer surgeries.

Regional anesthetic techniques commonly used on cancer surgeries.The activation of sensory neurons during pain enhances tumor progression and metastatic potential. Regional anesthesia blocks somatic nociception and inhibits sympathetic preganglionic outflow (functional sympathectomy) during surgery. Moreover regional anesthesia, by blocking sympathetic nervous system output, induces a prevalence of parasympathetic tone. Local anesthetics can also modulate autonomic receptors. For these reasons, more studies are needed to investigate the action of regional anesthetic neuromodulation on cancer progression.[11]

The Erector Spinae Plane Block (ESP block) is most often performed on thoracic paraspinal levels, causes sympathetic blockage. Sympathetic block has been studied on central neuraxial blocks but the sympathetic block caused by the ESP block and immune responses remain unclear.

Sympathetic block inhibits hyperbolic immune responses after surgery, therefore enhances postoperative rate of acceleration on cytokine levels. The investigators propose that ESP block improves immune responses and improved immune responses have better clinical outcomes for patients with breast cancer. Improved immune responses decrease length of stay (LOS), enhance postoperative recovery, analgesia and quality of life. Therefore allows better patient experience about procedures.

The investigators will take 90 patients who will undergo a breast cancer operation and compare vitals (heart rate, blood pressure, oxygen saturation), Numeric Rating Scales (NRS), Vascular Endothelial Growth Factor (VEGF) responses, systemic immune inflammatory indexes, cortisol levels, CRP and Procalcitonin levels between three groups; opioid analgesia group(group M), ESP block group(group E), non-opioid non-ESP group (group P).

The investigators' main focus is immune alterations after anesthesia techniques. Anesthesiologist keep track of pain scores after surgery. this trials secondary outcome focuses on pain management after surgery.

Inclusion criteria:

1. Should be female
2. Should be between 18-65 years old
3. Diagnosed with unilateral primary breast cancer
4. Are decided to have mastectomy surgery
5. Stage 1-2 breast cancer (T0-1-2, N0-1, M0)

Exclusion criteria from the:

1. Being allergic to the anesthetics
2. Previously had breast operation other than diagnostic biopsy
3. Presence of a malignancy history on the other breast
4. Diagnosed with Inflammatory breast cancer
5. Having a risk score of The American Society of Anaesthesiologists (ASA) risk score 3 and above
6. Contraindications for regional block(Allergies for local anesthetics, Anatomic application difficulties, Coagulopathies)
7. Hormone usage
8. NRS score greater than 3 before the operation
9. Opioid or steroid usage before the operation
10. Rheumatologic history
11. Sickness or drug usage that might cause immunosuppression
12. Chemotherapy and/or radiotherapy history
13. Concomitant history of previous malignancy
14. History of Coronary Artery Disease, Peripheral Vascular Disease that may affect VEGF
15. Chronic smoking
16. Chronic obstructive pulmonary disease
17. Presence of infection at the time of surgery
18. Hypothalamus, Pituitary, adrenal gland dysfunction
19. Autoimmune diseases

The investigators will evaluate unilateral breast cancer patients from Ankara Dr. Abdurrahman Yurtaslan Oncology Train and Research Hospital who will undergo Mastectomy procedure.

The investigators will exclude patients who no longer want to participate at any part of the trial.

A total of 90 patients' data will be collected.

The investigators will share Study Protocol, Statistical Analysis Plan (SAP), Informed Consent Form (ICF), Clinical Study Report

Data will become available starting 6 months from publication.

IPD will be shared with other clinical experimenters in order to serve as an example to similar studies and to demonstrate the reliability of the study. Consent forms of the participants, preoperative evaluation and postoperative follow-up forms, blood results evaluating inflammatory responses, postoperative analgesia need follow-up form will be open to sharing.