Histopathology report on colon cancer specimens; measuring surgical quality, an increasing stress for surgeons

Introduction. Improving the quality of surgical resections by evaluating surgical specimens is probably the most important feedback a surgeon can receive. Moreover, prognosis of patients with colon cancer is based on achieving appropriate resection margins and assessment of lymph node status. For these reasons we aim to provide a retrospective analysis on colon cancer specimens operated by a single surgical team. Materials and Methods. 88 patients operated between 2013 and 2016 were included in the study. Data were gathered prospectively and assessed by multivariate analysis for the main variables (age, gender, tumor staging, specimen length, distance to closest resection margin, number of lymph nodes, and number of positive lymph nodes). Results. The mean number of lymph nodes excised was 31,9, with more after right colectomies (39.6) than after left colonic resections (29.1). The average specimen length was 29.2cm after right colectomies, 35.6cm after left hemicolectomies and 18cm after segmental colectomies. There was a significant correlation between the number of lymph nodes, specimen length, and age of patients. Conclusion. Lymph node status is correlated with specimen length and age. The standard of 12 lymph nodes was achieved and surpassed, being comparable to the benchmark literature. Standards on colon resections need to be reevaluated as many surgeons are pressured by quality measurements which do not always reflect sound oncologic principles. Stefan Morarasu et al. 76 Introduction The number of lymph nodes excised in colon cancer surgery has been found to be critical to the overall survival rate of patients (1, 2). Besides their staging role, the number of lymph nodes correlates with KaplanMeyer survival curves. Surgeons with proper lymph node yields have better prognostic outcomes than surgeons with statistics below standards values (3, 4). The importance of extensive lymph node resection is not based on the therapeutic role but rather on the diagnostic and staging significance, as more lymph nodes in the specimen will lead to better staging and subsequently improved treatment for patients (5-9). A total of 12 retrieved lymph nodes are considered the standard of care. Variation in the numbers of retrieved nodes has been analyzed, and many factors have been proposed to influence the number of excised lymph nodes, including age, sex, tumor location, tumor stage, and the technique used for pathological assessment (10, 11). Perhaps the most important factor influencing appropriate lymph node excision is the surgeon him/herself. Technique of dissection, maintaining the correct anatomic plane, and central vascular ligation are all influencing factors that depend on the specific surgeon. Following anatomical planes in the course of dissection is imperative for proper specimen retrieval, an idea supported by Total Mesorectal Excision (TME). Heald (12) has thoroughly described the correct excision plane in rectal surgery, with such specimens proving far superior to previous ones (13). The logic of TME lies in respecting the embryological, avascular plane between the mesorectal and pelvic fascia, and with the advent of TME, rectal surgery has now become standardized. However, these planes may not be limited to the rectum, but rather can be found all along the colon such that Complete Mesocolic Excision (CME) has now been promoted as the standard surgical technique in colon surgery. Proponents of CME present superior lymph node counts and better oncological outcomes when CME is followed (14-17). Others argue that CME is simply a D3 lymphadenectomy, which Japanese and Taiwanese surgeons had already been doing before CME was proposed. Even so, the necessity of a standard procedure in colon surgery is obvious and underscored by the variability of lymph node retrieval and specimen length among surgeons worldwide. Comparative studies of specimens before and after adopting CME by the same surgeons show superior outcomes under the latter conditions. Regardless of the procedure, CME or D3 lymphadenectomy, correct dissection, central ligation, respecting oncological margins, and retrieving a proper specimen are critical for all the lymph nodes identified for excision. Evaluating the specimen is based on the number of lymph nodes excised, as the number of lymph nodes is an independent prognostic and staging factor in colon cancer. For these reasons, a thorough review of one`s specimens regarding lymph node count is or should be a must for improving surgical standards. Materials and Methods We conducted a prospective study of patients diagnosed with colon cancer between 2013 and 2016 who were operated by a single surgical team at the 2nd Surgical Unit, Regional Oncology Institute, Iasi, Romania. Data were prospectively collected in an excel database and included age, sex, operation date, intraoperative diagnostic and findings, preoperative staging, preoperative radio-chemotherapy, preoperative CEA and CA19-9 values, and histopathology report (histologic diagnosis, pTNM, specimen length, distance to resection margins, number of lymph nodes and number of positive lymph nodes). Only patients that had all the aforementioned details were included in the study. Postoperatively, patients were followed up at 3, 6, 12 months and annually thereafter by tumor marker levels, abdominal ultrasound, chest x-ray, and CT scans. Patients were called in for control to assess possible local recurrence and overall survival according to the Institute’s follow-up protocols. Data were grouped according to the type of procedure the patients underwent: right hemicolectomy, left hemicolectomy, segmental sigmoid resection, and transverse segmental colectomy. Rectal cancer cases were not included in the study. Specimens were measured after formalin fixation. No special techniques were used to harvest lymph nodes (e.g., fat clearance, blue dye injection). Multivariate data analysis was performed in Microsoft Excel using a logistic regression model; p<0.05 was considered statistically significant. Lymph Node Ratio (LNR) was calculated, defined by the ratio between positive lymph nodes and the total number of lymph nodes excised. Interquartile Range (IQR), mean, and min and max values were generated.