Monitoring oncological surgery using optical coherence tomography

Abstract

Development of local recurrence is one of the main causes of unsatisfactory long-term recovery prospects following cancer surgery. Determining the adequate balance between radical tumor removal and maximum preservation of the surrounding tissue is therefore very important for cancer management and, subsequently, the patient’s quality of life. Rates of recurrence following surgical resection are appreciably high for a number of cancers. Following transurethral resection of bladder tumors (TURBT), they are reported to be as high as 40–80%, with a 2–45% risk of progression to invasive disease, depending on the grade and stage of the original tumor.1 Because of these high rates, partial cystectomy (removal of a major portion of the bladder) is advised for 6% of bladder-cancer patients.2 Following rectal-cancer surgery, the majority of recurrences are observed within the first two years postsurgery and arise in 21–36% of patients.3 After surgery for esophageal adenocarcinoma, the tumor-recurrence rate in the resected region is 18%.4 This indicates that existing diagnostic methods have limited potential for determining the true extent of tumors. We have evaluated the use of optical coherence tomography (OCT) for preand intraoperative planning of tumor-resection margins for bladder, esophageal, and rectal carcinoma. OCT is an imaging method used to obtain cross-sectional images of living tissue in a noncontact and noninvasive manner by visualizing the distribution of backscattering intensities. TheOCT device we employed uses probing radiation at a wavelength of 1300nm and a power of 3mW. EachOCT image has 200×200 pixels across Figure 1. Intraoperative optical coherence tomography (OCT) planning of the resection line during transurethral resection of bladder tumors. (a) Schematic diagram of a tumor and locations of OCT images. (b) OCT image of tumor focus and (c) parallel histological image. (d) OCT image showing abnormal structure and (e) parallel histology indicating urothelial dysplasia. (f) OCT image with normal structure and (g) parallel histology of a normal bladder. Scale bars: 1mm.