Background: Mastectomy is a common surgical procedure done worldwide. Surgical site infection (SSI) is a common healthcare-associated infection. Mastectomy SSIs are frequently under-reported.

Objectives: The study aimed to determine the incidence of SSI among mastectomy cases of the Department of Surgery, University of the Philippines - Philippine General Hospital (UP-PGH) during one year of full implementation of the Surgical Site Infection Surveillance Program and evaluate the program's surveillance follow-up rate.

Methods: This study was an observational practice audit research that included all adult patients who underwent a mastectomy in UP-PGH from January 1, 2018, to January 31, 2019, when the SSI Surveillance Program was fully implemented. SSI was monitored and assessed during the patient's hospital stay, on the day of hospital discharge, and at 30 days (± 2 days) after surgery, either during an outpatient visit or via phone call by a nurse navigator. SSI frequency for mastectomy was computed both during the in-hospital stay and at 30 days after surgery. Surveillance follow-up rate, defined as the proportion of patients who could follow-up up to 30 days after surgery, was determined.

Results: The 30-day SSI rate for mastectomy was 6.8% (19/279). All 279 patients were followed up to 30 days after surgery. Of the 279 patients, 277 (99.3%) were through clinic visits, one was through phone calls, and one was still admitted to the hospital.

Conclusion: Full implementation of the SSI Surveillance Program for mastectomy in UP-PGH for one year showed a higher SSI rate than in published international literature. The program had a complete 30-day patient follow-up, contributing to more accurate SSI reporting. Implementing an SSI surveillance program with standardized protocols, dedicated personnel, patient education component, and the analysis of the information derived from such programs can improve an institution's quality of surgical care.