This prospective randomized controlled trial was conducted at the Department of Anesthesia, Shaukat Khanum Memorial Cancer Hospital and Research Centre (SKMCH&RC), Lahore. The sample size was calculated based on a previous study by Gad M. (2019) on patients undergoing modified radical mastectomy , where the mean morphine consumption in first 24 hours post operatively was reported as 16.7 ± 7.21 mg in the erector spinae plane (ESP) block group and 10.7 ± 3.12 mg in the pectoral plane block (PECS) group. Using the formula for comparison of two means with unequal standard deviations, and assuming a 90% power, 95% confidence interval, and a 10% dropout rate, the required sample size was determined to be 42 patients, with 21 patients in each group.

This prospective randomized controlled trial was conducted at the Department of Anesthesia, Shaukat Khanum Memorial Cancer Hospital and Research Centre (SKMCH&RC), Lahore. The sample size was calculated based on a previous study by Gad M. (2019) on patients undergoing modified radical mastectomy , where the mean morphine consumption in first 24 hours post operatively was reported as 16.7 ± 7.21 mg in the erector spinae plane (ESP) block group and 10.7 ± 3.12 mg in the pectoral plane block (PECS) group. Using the formula for comparison of two means with unequal standard deviations, and assuming a 90% power, 95% confidence interval, and a 10% dropout rate, the required sample size was determined to be 42 patients, with 21 patients in each group

Inclusion Criteria:

• ASA physical status II or III, biopsy proven breast cancer, and were undergoing unilate l modified radical mastectomy

Exclusion Criteria:

• . Exclusion criteria included patient refusal to participate, age less than 18 years, diagnosed allergy or contraindication to local anesthetic, chronic pain, obesity (BMI >35), non-cancerous or undiagnosed breast lesions, ASA IV status, and emergency surgery.