A prospective study of the length of the distal margin after low anterior resection for rectal cancer

Measurement of distal intramural spread and the optimal distal resection by naked eyes after neoadjuvant radiation for rectal cancers

Background

The safe distance between the intraoperative resection line and the visible margin of the distal rectal tumor after preoperative radiotherapy is unclear. We aimed to investigate the furthest tumor intramural spread distance in fresh tissue to determine a safe distal intraoperative resection margin length.

Methods

Twenty rectal cancer specimens were collected after preoperative radiotherapy. Tumor intramural spread distances were defined as the distance between the tumor’s visible and microscopic margins. Visible tumor margins in fresh specimens were identified during the operation and were labeled with 5 - 0 sutures under the naked eye at the distal 5, 6, and 7 o’clock directions of visible margins immediately after removal of the tumor. After fixation with formalin, the sutures were injected with nanocarbon particles. Longitudinal tissues were collected along three labels and stained with hematoxylin and eosin. The spread distance after formalin fixation was measured between the furthest intramural spread of tumor cells and the nanocarbon under a microscope. A positive intramural spread distance indicated that the furthest tumor cell was distal to the nanocarbon, and a negative value indicated that the tumor cell was proximal to the nanocarbon. The tumor intramural spread distance in fresh tissue during the operation was 1.75 times the tumor intramural spread distance after formalin fixation according to the literature.

Results

At the distal 5, 6, and 7 o’clock direction, seven (35%), five (25%), and six (30%) patients, respectively, had distal tumor cell intramural spread distance > 0 mm. The mean and 95% confidence interval of tumor cell intramural spread distance in fresh tissue during operation was − 0.3 (95%CI − 4.0 ~ 3.4) mm, − 0.9 (95%CI − 3.4 ~ 1.7) mm, and − 0.4 (95%CI − 3.5 ~ 2.8) mm, respectively. The maximal intraoperative intramural spread distances in fresh tissue were 8.8, 7, and 7 mm, respectively.

Conclusions

The intraoperative distance between the distal resection line and the visible margin of the rectal tumor after radiotherapy should not be less than 1 cm to ensure oncological safety.

Distal resection margins in rectal cancer specimens: differences in assessment between surgeons and pathologists and the influence of neoadjuvant chemoradiation

To investigate the discrepancy between the distal resection margin (DRM) assessed by surgeons and pathologists, and the impact of neoadjuvant chemoradiotherapy (nCRT) on DRM. This study included 67 rectal cancer patients undergoing elective surgery. DRMs were assessed through four different techniques: in vivo subjective estimative, made by the surgeon before the rectal resection (by palpation and visual estimative); in vivo objective, measured with a ruler before the rectal transection; ex vivo objective, measured right after resection of the specimen; post-fixation objective measurement, conducted by the pathologist. The DRMs subjectively and objectively assessed by the surgeons were not significantly different (3.40 cm vs. 3.45 cm). There was a mean reduction in the length of DRMs of 35.6%, from 3.45 cm objectively measured by the surgeon to 2.20 cm measured by the pathologist. This difference was significant among patients that did not receive nCRT (3.90 cm vs. 2.30 cm, P < 0.001), but not among those who received nCRT (2.30 vs. 2.05 cm). Surgeons are accurate in assessing rectal cancer DRMs. There are significant differences between intraoperative measurements of DRMs and the final pathologic results. However, these differences are not seen when nCRT is used, a finding that may be useful when sphincter preservation is being considered.

Shrinkage of specimens after CO2 laser cordectomy: an objective intraoperative evaluation

PURPOSE

The margin status after CO₂ laser cordectomy for glottic carcinoma may influence prognosis. There are no studies assessing the possible bias due to anatomic changes of the specimens for shrinkage. The authors evaluated the intraoperative shrinkage of specimens immediately after transoral CO₂ laser microsurgery (CO₂ TOLMS) to improve the understanding and the interpretation of surgical margins.

METHODS

This is a prospective study involving a consecutive cohort of 23 patients (19 males, 4 females, mean age 69.9 years, range 42-83 years) with early glottic carcinoma treated by CO₂ TOLMS from February 2017 to April 2019. The anteroposterior shrinkage of the specimen, of the tumor, and of the anterior and posterior margins was measured intraoperatively with a cross table reticle glass micrometer ruler, inserted into the eyepiece of the surgical microscope.

RESULTS

The mean shrinkage of the mucosal specimen from intralaryngeal measurement to post-resection measurement was 3.8 ± 0.3 mm, resulting in an average loss of 29% of the anteroposterior length (p < 0.01). The anteroposterior length of both the tumor and the margins after resection significantly decreased, but the shrinkage of the anterior and posterior margins was significantly greater than the shrinkage of the tumor (49% versus 20% and 45% versus 20%, p < 0.01).

CONCLUSION

The present study demonstrates significant shrinkage of specimens after CO₂ TOLMS, especially in the anteroposterior length of the vocal cords, and justifies the good oncological results for specimens with close and single positive superficial margins. Follow-up versus a second surgical look policy could be safely suggested in cases of close superficial and single positive superficial margins.

Prognostic Impact of the Length of the Distal Resection Margin in Rectosigmoid Cancer: An Analysis of the JSCCR Database between 1995 and 2004

Objectives

The necessary and sufficient length of the distal resection margin (l-DRM) for rectosigmoid cancer remains controversial. This study evaluated the validity of the 3-cm l-DRM rule for rectosigmoid cancer in the Japanese classification of colorectal cancer.

Methods

We retrospectively reviewed 1,443 patients with cT3 and cT4 rectosigmoid cancer who underwent R0 resection in Japanese institutions between 1995 and 2004. We identified the optimal cutoff point of the l-DRM affecting overall survival (OS) rate using a multivariate Cox regression analysis model. Using this cutoff point, the patients were divided into two groups after balancing the potential confounding factors of the l-DRM using propensity score matching, and the OS rates of the two groups were compared.

Results

A multivariate Cox regression analysis model revealed that the l-DRM of 4 cm was the best cutoff point with the greatest impact on OS rate (hazard ratio [HR], 1.37; 95% confidence interval [CI], 1.00-1.84; P = 0.0452) and with the lowest Akaike information criterion value. In the matched cohort study, the OS rate of patients who had l-DRM of 4 cm or more was significantly higher than that of patients who had l-DRM < 4 cm (n = 402; 5-year OS rates, 87.6% vs. 80.3%, respectively; HR, 1.60; 95% CI, 1.09-2.31; P = 0.0136).

Conclusions

For cT3 and cT4 rectosigmoid cancer, l-DRM of 4 cm may be an appropriate landmark for a curative intent surgery, and we were unable to definitively confirm the validity of the Japanese 3-cm l-DRM rule.

Impact of Length of Distal Margin on Outcomes Following Sphincter Preserving Surgery for Middle and Lower Third Rectal Cancers

Outcomes of sphincter preserving surgery for distal rectal cancers improve with clear circumferential resection and distal resection margin. However, the extent of distal resection margin after a complete mesorectal excision is often a cause for debate. We evaluated the outcome of middle and lower third rectal cancer patients undergoing sphincter preservation with variable distal resection margin at our center. Patients with biopsy-proven rectal adenocarcinoma within 10 cm from anal verge undergoing sphincter preserving resections were included. Patients with positive circumferential resection margin were excluded. Patients were divided into three groups based on the extent of distal resection margin (< 6 mm, 6-10 mm, > 10 mm) and oncological outcomes were compared. The median age of 242 patients was 50 years and 44 (18.2%) were high-grade tumors. Preoperative chemoradiation was used in 185 (75.2%) patients. Median distal resection margin was 20 mm. Patients in < 10 mm group had a significantly higher proportion of lower third (68.3% vs 39.8%, p = 0.004) and chemoradiation-treated tumors (85.4 vs 74.6%, p = 0.001). A significantly higher percentage required an intersphincteric resection in the < 10 mm group (53.7% vs 14.4%, p = 0.0001). Significantly higher percentage tumors were pT3 in > 10 mm group (45.3% vs. 31.7%) (p = 0.05). The median follow-up was 23 months. There was no difference in the overall, loco-regional, and distant recurrence rates between the three groups. A subcentimeter distal resection margin does not influence loco-regional or distant recurrence rates following sphincter preserving surgery for middle and lower third rectal adenocarcinoma.

Comparative study of electrical and rheological properties of different solutions used in endoscopic mucosal resection

BACKGROUND AND AIM

The study of electrical and rheological properties of solutions to carry out endoscopic resection procedures could determinate the best candidate. An ex vivo study with porcine stomachs was conducted to analyze electrical resistivity (R) and rheological properties (temperature, viscosity, height and lasting of the cushion) of different substances used in these techniques.

METHODS

Tested solutions were: 0.9% saline (S), platelet-rich plasma (PRP), Gliceol (GC), hyaluronic acid 2% (HA), Pluronic-F127 20% (PL), saline with 10% glucose (GS), Gelaspan (GP), Covergel-BiBio (TB) and PRP with TB (PRP+TB). Measurements of electrical and rheological properties were done at 0, 15, 30, 45 and 60 min after submucosal injection.

RESULTS

Solutions showed a wide variability of transepithelial R after submucosal injection. Substances able to maintain the highest R 60 min postinjection were TB (7 × 10⁴ Ω), HA (7 × 10⁴ Ω) and PL (7 × 10⁴ Ω). Protective solutions against deep thermal injury (Tª lower than 60°C) were PL (47.6°C), TB (55°C) and HA (56.63°C). Shortest time to carry out resections were observed with GC (17.66″), PRP (20.3″) and GS (23.45″). Solutions with less cushion decrease (<25%) after 60 min were TB (11.74%), PL (18.63%) and PRP (22.12%).

CONCLUSIONS

Covergel-BiBio, PL and HA were the best solutions with long-term protective effects (transepithelial R, lower thermal injury and less cushion decrease). Solutions with quicker resection time were GC, PRP and GS.

Tissue expansion of lung bronchi due to tissue processing for histology - A comparative analysis of paraffin versus frozen sections in a pig model

AIM

Tissue shrinking due to fixation and processing is well known. However, the degree of shrinking varies significantly with the tissue type as well as the processing method and is not well studied in various tissues. In daily pathological routine workflow, histological specimens from frozen and paraffin sections are performed from the same tissue. In the present study we compared the thickness of bronchus walls obtained from paraffin and frozen sections.

METHODS

Pig lungs were frozen in ventilated condition in liquid nitrogen and 36 bronchi were isolated after dissection. Frozen sections of 5 μm thickness were performed and the remaining tissue was fixed and embedded in paraffin after fixation in 4% formalin. Frozen and paraffin sections from the same cutting edge were analysed after haematoxylin and eosin staining by measuring the wall thickness of the bronchi using high power fields of 400-fold magnification. In each bronchus 40 measurements were implemented at different wall positions distributed over the entire wall area. Summed up, in each group 1440 wall measurements were performed in total. Statistical analysis was conducted using the Wilcoxon test and t-test as well as Pearson's correlation coefficient with a significance level at P < 0.05.

RESULTS

The bronchial wall thickness was significantly (p < 0.001) smaller in frozen sections (median: 0.50 mm; min: 0.37 mm; max: 0.97 mm) compared to paraffin sections (median: 0.58 mm; min: 0.35 mm; max: 1.06 mm). The median difference between paraffin and frozen sections was 0.05 mm (min: -0.11 mm; max: 0.22 mm). The wall thickness ratio of both groups was as follows: frozen/paraffin section = 0.8609, thus yielding a difference between paraffin and frozen of 13.91%. High correlation was found between wall thickness measurements on paraffin and frozen sections (R = 0.87, p < 0.001).

CONCLUSIONS

The bronchus wall thickness in the frozen section was 14% reduced compared to the paraffin section. In routine pathology as well as in scientific studies these results are of relevance, as airway wall thickness represents a relevant marker for pathological interpretation, especially using CT image techniques.

Oncologic outcomes in rectal cancer patients with a ≤1-cm distal resection margin

PURPOSE

Recently, common application of sphincter-saving resection in rectal cancer has led to acceptance of a 1-cm distal resection margin (DRM). The aim of this study was to evaluate oncologic outcomes of a DRM ≤1 cm in sphincter-saving resection for rectal cancer. The outcomes of a DRM ≤0.5 cm was also evaluated.

METHODS

We reviewed prospectively collected data from 415 patients who underwent sphincter-saving resection for mid and low rectal cancer between September 2006 and December 2012 at Korea University Anam Hospital. Patients were divided into two groups according to DRM measured in a formalin fixed specimen: ≤1 cm (n = 132) and >1 cm (n = 283). The DRM ≤1 cm group was divided into two subgroups: ≤0.5 cm (n = 45) and >0.5, ≤1 cm (n = 87).

RESULTS

Median follow-up periods were 47.2 months. The 5-year local recurrence rate was 8.8% in the DRM ≤1 cm group and 8.5% in the DRM >1 cm group (p = 0.630). The 5-year disease-free survival rate was 75.1 and 76.3% (p = 0.895), and the 5-year overall survival rate was 82.6 and 85.9% (p = 0.401), respectively. In subanalysis of the DRM ≤1 cm group, there was also no significant difference in the local recurrence and survival.

CONCLUSIONS

There was no significant difference in local recurrence and survival based on DRM length. We found that DRM length less than 1 cm was not a prognostic factor for local recurrence or survival.

Objective measurement of the distal resection margin by MRI of the fresh and fixed specimen after partial mesorectal excision for rectal cancer: 5 cm is not just 5 cm and depends on when measured

BACKGROUND

Most studies have directly established the optimal perioperative in situ clearance margin in surgery for rectal cancer from the histologically observed extent of distal spread, neglecting the tissue variability that occurs after resection and fixation of the rectal specimen.

PURPOSE

To measure the length of the distal resection margin in the fresh and fixed specimen following partial mesorectal excision for rectal cancer using magnetic resonance imaging (MRI) to document tissue shrinkage after surgical removal and fixation.

MATERIAL AND METHODS

The length of the distal resection margin was measured by MRI of the fresh and fixed specimen and at histopathological examination of the fixed specimen in 10 patients who underwent surgery for upper rectal cancer. In addition, tissue shrinkage was estimated by measuring the total length of the fresh and fixed specimen and distance from the peritoneal reflection anteriorly to the distal cut edge of the specimen.

RESULTS

Measured by MRI, the distal resection margin was in the range of 0.6-10.2 cm (mean, 4.6 cm) in the fresh specimen, and 0.5-6.2 cm (mean, 3.2 cm) in the fixed specimen. The tissue shrinkage ratio was a mean of 69% (interquartile range, 61-77%). Taking all ratios from MRI and histopathological examination of tissue shrinkage into account, the collective tissue shrinkage ratio was 70% (95% confidence interval, 67-73%)

CONCLUSION

The length of the distal resection margin was reduced by 30% after surgical removal and fixation of the specimen.

The Influence of the Distal Resection Margin Length on Local Recurrence and long- term Survival in Patients with Rectal Cancer after Chemoradiotherapy and Sphincter- Preserving Rectal Resection

Background

Low recurrence rates and long term survival are the main therapeutic goals of rectal cancer surgery. Complete, margin- negative resection confers the greatest chance for a cure. The aim of our study was to determine whether the length of the distal resection margin was associated with local recurrence rate and long- term survival.

Patients and methods

One hundred and nine patients, who underwent sphincter-preserving resection for locally advanced rectal cancer after preoperative chemoradiotherapy between 2006 and 2010 in two tertiary referral centres were included in the study. Distal resection margin lengths were measured on formalin-fixed, pinned specimens. Characteristics of patients with distal resection margin < 8 mm (Group I, n = 27), 8–20 mm (Group II, n = 31) and > 20 mm (Group III, n = 51) were retrospectively analysed and compared. Median (range) follow-up time in Group I was 89 (51–111), in Group II 83 (57–111) and in Group III 80 (45–116) months (p = 0.326), respectively.

Results

Univariate survival analysis showed that distal resection margin length was not statistically significantly associated with overall survival or local recurrence rate (p > 0.05). In a multiple Cox regression analysis, after adjusting for pathologic T and N stage (yT, yN), distal resection margin length was still not statistically significantly associated with overall survival.

Conclusions

Our study shows that close distal resection margins can be accepted as oncologically safe for sphincter-preserving rectal resections after preoperative chemoradiotherapy.

Oncologically safe distal resection margins in rectal cancer patients treated with chemoradiotherapy

INTRODUCTION

Although current guidelines recommend distal resection margins (DRM) of 2-5 cm in rectal cancer operation, smaller margins may be safe. We therefore assessed the impact of distal margins on outcomes in patients with rectal cancer treated with neoadjuvant chemoradiotherapy (CRT) followed by radical resection or resection followed by adjuvant CRT.

MATERIALS AND METHODS

This study involved 376 patients who underwent sphincter-saving resection for rectal adenocarcinoma and pre- or postoperative CRT between 2000 and 2006. DRMs were measured on pinned fixed specimens. We excluded patients who did not complete planned CRT and those with stage IV disease. A retrospective cross-sectional analysis was performed.

RESULTS

No significant differences in local recurrence (9.8 versus 7.3%; P = 0.324) and systemic recurrence (16.4 versus 18.7%; P = 0.731) were observed in patients with DRMs of ≤5 and >5 mm, respectively. Moreover, in each DRM category, there were no differences in local and systemic recurrence rates between patients who received pre- or postoperative CRT. DRM did not affect overall survival (P = 0.880) or 5-year survival rate (80.3 versus76.8%; P = 0.340).

CONCLUSION

A distal margin of at least 5 mm with negative resection margin on frozen section does not reduce oncological safety in rectal cancer patients who receive pre- or postoperative CRT.

Adequate length of the distal resection margin in rectal cancer: from the oncological point of view

INTRODUCTION

The distal resection margin (DRM) has been considered an important factor for the oncological outcome of rectal cancer surgery. However, the optimal distal margins required to achieve safe oncological outcome remains to be controversial.

MATERIAL AND METHODS

More recently, as circumferential resection margin or mesorectal margin has been additionally reported to be more important factors predicting patient outcome than the distal mucosal margin, a re-evaluation of the impact of DRM on patient outcome is needed.

RESULTS

The extent of distal tumor spread is known to be influenced by a variety of factors such as tumor location, lymph node metastasis, and tumor size. DRM might affect survival more than a local recurrence. Because distal intramural tumor spread rarely exceeds 1 to 2 cm in most rectal cancers, and local control and survival do not seem to be compromised by shorter distal resection margins, the generally accepted practice is to aim for a 2-cm DRM. However, in the recent trend of curative resection after preoperative chemoradiotherapy, with an otherwise favorable tumor such as well-differentiated tumor and no lymph node metastasis, a DRM at < or =1 cm does not necessarily portend a poor prognosis. In cases with preoperative chemoradiotherapy, distal resection margins need to be evaluated individually.

DISCUSSION

It has been suggested that down-staging of low-lying rectal cancers after preoperative radiation might well include the pathological clearance of distal intramural microscopic spread. Moreover, the measurement of DRM varies with respective study, making it difficult to compare.

CONCLUSION

We need an applicable intraoperative method to accurately measure distal resection margin, enabling comparative outcome.

Comparative performance of novel solutions for submucosal injection in porcine stomachs: An ex vivo study

BACKGROUND

Submucosal injection of normal saline (NS) is commonly used during endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) but is quickly absorbed. Sodium hyaluronate (SH) produces longer lasting mucosal elevation but is expensive.

AIMS

To evaluate the performance of novel solutions for submucosal injection in comparison with NS and SH.

METHODS

One ml of the following solutions was injected in the submucosa of fresh specimens of porcine stomachs: NaCl 0.9%, SH 0.4%, human albumin 25%, two artificial tears solutions, namely, hydroxypropyl methylcellulose (HPMC) 0.3%/dextran 70.1% and polyvinyl alcohol (PVA) 1.4%, hydroxyethyl starch (HES) 6% and polyethylene glycol (PEG) 50%. The time until the disappearance of the mucosal elevation was recorded in a blind manner.

RESULTS

The median duration of mucosal elevation was significantly longer with HPMC/dextran, PVA, HES, PEG and SH (29, 26, 38, 31.5, and 41.5min, respectively) compared with NS (12min) (p<0.05 for each comparison). There were no significant time differences between SH and HPMC/dextran, HES and PEG (p>0.05).

CONCLUSIONS

Novel viscous or hypertonic solutions for submucosal injection, perform better than normal saline and equally well as sodium hyaluronate in porcine stomachs in vitro.

Intraoperative consultation (IOC) in mucosal lesions of the upper aerodigestive tract

Intraoperative consultation (frozen section) plays an important part in the treatment of the head and neck cancer patient. The appropriate use of intraoperative consultations (frozen sections) usually results in a definitive diagnosis with immediate therapeutic impact while the patient is in the operating room. Among the determinations made by frozen section analysis include the evaluation of adequacy of surgical margins of resection; the differentiation between nonneoplastic, benign and malignant proliferations; the evaluation of lymph nodes for the presence of metastatic disease; the determination of specimen identification and specimen adequacy, including the verification of such organs as the parathyroid glands; and the determination of whether a given case requires special diagnostic testing best performed on frozen material, such as for lymphomas. This paper focuses on intraoperative consultation of mucosal lesions of the upper aerodigestive tract, including epithelial dysplasia and squamous cell carcinoma. Other issues that often not diagnosed or at issue at the time of surgery, including the diagnosis of microinvasive carcinoma and differentiating inflammatory lesions from neoplastic lesions are included for completion.

Comparison of the characteristics of submucosal injection solutions used in endoscopic mucosal resection

OBJECTIVE

Submucosal injection is used to prevent complications, such as perforation, during endoscopic mucosal resection (EMR). Since injection of normal saline produces mucosal elevation of short duration, repeated injection is needed for extensive resection. To overcome this limitation, various submucosal injection solutions have been developed but there are few data comparing their efficacy. This study was therefore conducted to compare the physical and chemical properties and the duration of mucosal elevation of various submucosal injection solutions.

MATERIAL AND METHODS

A fresh transverse colon specimen acquired from a mongrel was used. Experiments were repeated four times. To compare the efficacy of mucosal elevation, 1 ml of each solution was injected into the submucosa: 0.9% NaCl, 20% mannitol, 0.1% sodium hyaluronate, 0.3% hydroxypropyl methylcellulose (HPMC), and 2% fibrinogen. Physical and chemical properties such as viscosity and osmolarity were compared.

RESULTS

The heights of initial mucosal elevations were 6.52+/-0.26 mm, 6.87+/-0.05 mm, 6.92+/-0.09 mm, 6.90+/-0.08 mm, and 6.90+/-0.08 mm for normal saline, mannitol, sodium hyaluronate, HPMC, and fibrinogen, respectively. Whereas injection of normal saline took about 20 min and mannitol about 30 min for the initial elevation to be reduced to more than half the initial height, it took more than 60 min for all the other agents. A correlation was found between the duration of mucosal elevation and viscosity but not with osmolarity.

CONCLUSIONS

The mucosal elevation lasted longer with sodium hyaluronate, HPMC, and fibrinogen than with mannitol or normal saline, and this seems to be due to the viscosity rather than the osmolarity of each solution.

Using p53-immunostained large specimens to determine the distal intramural spread margin of rectal cancer

AIM: To determine the distal intramural spread (DIS) margin of rectal cancer.

METHODS: Sixty-one p53-positive specimens of rectal cancer were used. After conventional hematoxylin and eosin (H&E) staining, the DIS margin of rectal cancer in large specimens was examined by immunohistochemistry. The patients were divided into A, B, C, and D groups. After a long-term follow-up, the survival curves of the four groups were estimated using the life table.

RESULTS: Fifty-one of the sixty-one cases (83.6%) had DIS. The extent of DIS ranged 0.11-3.5 cm; meanwhile the mean of DIS measured by H&E staining was 0.13 cm. The significant difference was found between the means (t=5.622, P<0.0001). Only 1 of 51 patients had DIS greater than 3 cm. The DIS was less than 1.0 cm in most rectal cancer patients. The long-term results indicated that the survival rate of the patients whose DIS was greater than 1.0 cm was lower than that of the patients whose DIS was less than 0.5 cm.

CONCLUSION: Rectal cancer patients with DIS greater than 1.0 cm have poor prognosis.

Post-resection mucosal margin shrinkage in oral cancer: quantification and significance

BACKGROUND

The importance of tumor free margins in outcome of cancer surgery is well known. Often the pathological margins are reported to be significantly smaller than the in situ margins. This discrepancy is due to margin shrinkage the quantum of which has not been studied in patients with oral cancers.

OBJECTIVES

To quantify the shrinkage of mucosal margin following excision for carcinoma of the oral tongue and buccal mucosa.

METHODS

Mucosal margins were measured prior to resection and half an hour after excision in 27 patients with carcinoma of the tongue and buccal mucosa. The mean margin shrinkage was assessed and the variables affecting the quantum of shrinkage analyzed.

RESULTS

The mean shrinkage from the in situ to the post resection margin status was 22.7% (P < 0.0001). The mean shrinkage of the tongue margins was 23.5%, compared to 21.2% for buccal mucosa margins. The mean shrinkage in T1/T2 tumors (25.6%) was significantly more than in T3/T4 (9.2%, P < 0.011).

CONCLUSIONS

There is significant shrinkage of mucosal margins after surgery. Hence this should be considered and appropriate margins should be taken at initial resection to prevent the agony of post-operative positive surgical margins.

Quantification of surgical margin shrinkage in the oral cavity

BACKGROUND

Obtaining adequate surgical margins, free of tumor, is crucial for success in oncologic surgery. The head and neck surgeon often finds that the tumor-free margin reported from histopathologic measurement is significantly smaller than the margin measured in-situ. It was the purpose of this study to quantify the change in size of mucosal and muscle surgical margins following excision, formalin fixation, and slide preparation of tongue and labiobuccal tissue in a canine model.

METHODS

Ten mongrel dogs under general anesthesia for a concurrent project were used in this study. Changes in mucosal and muscle dimensions around custom-made brass disks, one with a needle depth gauge, were measured immediately following excision after formalin fixation and after slide preparation.

RESULTS

The mean shrinkage from initial resection to final microscopic assessment of the lingual surface mucosal margins was 30.7% (p < 0.0001). The deep tongue margin shrank 34.5% (p < 0.0001). The mean shrinkage of the labiobuccal mucosal margin was 47.3% (p < 0.0001). In all cases, the greatest proportion of shrinkage occurred immediately upon resection.

CONCLUSIONS

From the in-situ measurement by the surgeon to final pathologic evaluation on the microscope slide, the measured dimensions of oral cavity mucosal and tongue muscle margins shrink significantly. To obtain 5 mm of pathologically clear margin an in-situ margin of resection of at least 8 to 10 mm needs to be taken. Studies reporting clinical correlation of recurrence and survival information with surgical margin status should include a detailed description of the technique used to determine the reported surgical margin status.

Local and regional recurrence of carcinoma of the colon and rectum: II. Factors relating to operative technique

Despite many recent advances in the field of radiation therapy, chemotherapy and even immunotherapy, surgical resection remains the mainstay of curative treatment for carcinoma of the colon and rectum. Locoregional recurrence is a recognized type of failure, and it is the most direct measurement of the relevance of surgery to cancer control. Factors that influence relapse rates and sites deserve in-depth and periodical review. Local or locoregional (LR) recurrence implies the reappearance of carcinoma after an intended complete removal of the tumour. It is usually defined as tumour regrowth at the anastomosis or immediately within or contiguous to the operative area. For rectal cancer, the adjacent organs include the perineum, bladder and vagina; and LR failure includes perineal or pelvic lesions. Many reports studied only patients with colon or rectal cancers, while others presented their data of the colon and rectum together. In this review, I shall use colon, rectum and colorectum to designate the composition of each patient population. Published results from all available English sources were reviewed, concentrating on reports of the last 10 years. Data analysed by statistical methods are emphasized, and a probability of occurrence of one in 20 or less (P < 0.05) is considered significant. Various clinicopathological factors of the tumour and host, and adjuvant radiotherapy that affected the LR recurrence rates have been presented in another paper (part 1, 283 - 293). Technical details and issues relating to performance of the operation will be discussed in this paper (part II). Quantitative information presented here predate the wide use of laparoscopic or minimal invasive surgery in treating the primary tumour, and the polar practice of periodic colonoscopy, carcinoembryonic antigen (CEA) or computed tomography as regular follow-up tests. Thus, these baseline data will be useful to study the changes in rates and sites of recurrence in the future.

Total mesorectal excision and local recurrence: a study of tumour spread in the mesorectum distal to rectal cancer

Total mesorectal excision (TME) appears to be associated with a reduced local recurrence rate following surgery for rectal cancer. Of 20 patients with rectal cancer in whom TME was performed, adenocarcinoma was found in the distal mesorectum in four. Distal mesorectal spread often extended further than intramural spread. Patients with tumour in the distal mesorectum had a worse outcome at 4-year follow-up, a greater risk of local recurrence and an increased frequency of distant metastasis. Distal tumour spread is, therefore, a marker of poor prognosis in rectal cancer. This study provides further evidence that incomplete excision of the mesorectum contributes to local recurrence in a proportion of patients with rectal cancer, particularly in those with tumours in the middle and lower third of the rectum.

Total rectal resection and colo-anal anastomosis with colonic reservoir for low rectal cancer

From March 1990 to December 1992, 47 patients with primary or recurrent low rectal cancer underwent total rectal resection and a coloendoanal anastomosis. Rectal resection was extended downward to the ano-rectal junction. The restorative technique included a colo-endoanal anastomosis between the dentate line and a J-shaped colic reservoir. All lesions were located within 7 cm of the anal verge (within 6 cm in 33 primary cases). Macroscopic and histological radicality was documented in all cases. Pelvic recurrence occurred in six patients and was para-anastomotic in one case. Post-operative morbidity was low. Perfect continence was documented in 36 patients and 72 of the cases had one or two bowel movements a day. All but four patients are alive at a follow-up ranging from 6 to 40 months (median 20 months). This approach is a safe option to conventional total rectal excision with permanent colostomy for lower third rectal carcinoma.

Adequate distal margin of resection for adenocarcinoma of the rectum

There are two questions in the surgical treatment of rectal cancer: (1) How far below a palpable rectal cancer should a surgeon cut in order to avoid cutting through cancer and, (2) Given that the surgeon has not cut through cancer, could the chance of subsequent recurrent rectal cancer have been reduced if an even greater length of bowel had been removed. For mobile tumors that are not poorly differentiated the answer to the first question is far enough in order to get a right-angled clamp on below the tumor that will not slip; the answer to the second question is no.