45 patients undergoing neoadjuvant treatment (stages II to IIIB) will undergo breath sampling (1) at baseline before any treatment, (2) 2 weeks after neoadjuvant therapy, (3) 2 weeks after surgery, (4) 6 months after surgery, and (5) every 6 months for the first 2 years. Blood sample collections will coincide with the breath collection schedule.

15 patients who are planned to undergo upfront surgery will undergo breath sampling (1) at baseline before upfront surgery, (2) 2 weeks after surgery, (3) 6 months after surgery, and (4) every 6 months for the first 2 years.

Cohort 1: patients undergoing neoadjuvant treatment (stages II to IIIB) will undergo breath sampling (1) at baseline before any treatment, (2) 2 weeks after neoadjuvant therapy, (3) 2 weeks after surgery, (4) 6 months after surgery, and (5) every 6 months for the first 2 years.

Cohort 2: patients who are planned to undergo upfront surgery will undergo breath sampling (1) at baseline before upfront surgery, (2) 2 weeks after surgery, (3) 6 months after surgery, and (4) every 6 months for the first 2 years.

obtained using E-nose technology, all patients who have pre-neoadjuvant treatment E-nose testing, pre-surgery E-nose testing, 2 week post-surgery E-nose testing, and E-nose testing every 6 months for 2 years will be considered evaluable for the primary endpoint of Major Pathologic Response (MPR). Patients with MPR confirmed on pathologic analysis will be considered to have had an MPR, whereas all other evaluable patients will be considered to have not had an MPR, in accordance with the intention-to-treat analysis.

Differences in VOC expression between time-point assessments will be calculated in terms of VOC percentage change from baseline to assess the magnitude of change among patients with and without progression, particularly at earlier time points. Here, progression is considered as a binary endpoint, where progression includes recurrence, disease progression, or death within 2 years.

Differences in VOC expression between time-point assessments will be calculated in terms of VOC percentage change from baseline to assess the magnitude of change among patients with and without progression, particularly at earlier time points. Here, progression is considered as a binary endpoint, where progression includes recurrence, disease progression, or death within 2 years.