Extramural Venous Invasion and Tumor Deposit at Diffusion-weighted MRI in Patients after Neoadjuvant Treatment for Rectal Cancer

Background Diffusion-weighted (DW) imaging is useful in detecting tumor in the primary tumor bed in locally advanced rectal cancer (LARC) after neoadjuvant therapy, but its value in detecting extramural venous invasion (EMVI) and tumor deposit is not well validated. Purpose To evaluate diagnostic accuracy and association with patient prognosis of viable EMVI and tumor deposit on DW images in patients with LARC after neoadjuvant therapy using whole-mount pathology specimens. Materials and Methods This retrospective study included patients who underwent neoadjuvant therapy and surgery from 2018 to 2021. Innovative five-point Likert scale was used by two radiologists to independently evaluate the likelihood of viable EMVI and tumor deposit on restaging DW MRI scans in four axial quadrants (12 to 3 o'clock, 3 to 6 o'clock, 6 to 9 o'clock, and 9 to 12 o'clock). Diagnostic accuracy was assessed at both the per-quadrant and per-patient level, with whole-mount pathology as the reference standard. Weighted κ values for interreader agreement and Cox regression models for disease-free survival and overall survival analyses were used. Results A total of 117 patients (mean age, 56 years ± 12 [SD]; 70 male, 47 female) were included. Pathologically proven viable EMVI and tumor deposit was detected in 29 of 117 patients (25%) and in 44 of 468 quadrants (9.4%). Per-quadrant analyses showed an area under the receiver operating characteristics curve of 0.75 (95% CI: 0.68, 0.83), with sensitivity and specificity of 55% and 96%, respectively. Good interreader agreement was observed between the radiologists (κ = 0.62). Per-patient analysis showed sensitivity and specificity of 62% and 93%, respectively. The presence of EMVI and tumor deposit on restaging DW MRI scans was associated with worse disease-free survival (hazard ratio [HR], 5.6; 95% CI: 2.4, 13.3) and overall survival (HR, 8.9; 95% CI: 1.6, 48.5). Conclusion DW imaging using the five-point Likert scale showed high specificity and moderate sensitivity in the detection of viable extramural venous invasion and tumor deposits in LARC after neoadjuvant therapy, and its presence on restaging DW MRI scans is associated with worse prognosis. Published under a CC BY 4.0 license. Supplemental material is available for this article. See also the editorial by Méndez and Ayuso in this issue.

An immunocompetent rectal cancer model to study radiation therapy

We describe a mouse model of rectal cancer (RC) involving rapid tumor organoid engraftment via orthotopic transplantation in an immunocompetent setting. This approach uses simple mechanical disruption to allow engraftment, avoiding the use of dextran sulfate sodium. The resulting RC tumors invaded from the mucosal surface and metastasized to distant organs. Histologically, the tumors closely resemble human RC and mirror remodeling of the tumor microenvironment in response to radiation. This murine RC model thus recapitulates key aspects of human RC pathogenesis and presents an accessible approach for more physiologically accurate, preclinical efficacy studies.

Synthesis of robust hierarchical silica monoliths by surface-mediated solution/precipitation reactions over different scales: designing capillary microreactors for environmental applications

A synthetic procedure to prepare novel materials (surface-mediated fillings) based on robust hierarchical monoliths is reported. The methodology includes the deposition of a (micro- or mesoporous) silica thin film on the support followed by growth of a porous monolithic SiO2 structure. It has been demonstrated that this synthesis is viable for supports of different chemical nature with different inner diameters without shrinkage of the silica filling. The formation mechanism of the surface-mediated fillings is based on a solution/precipitation process and the anchoring of the silica filling to the deposited thin film. The interaction between the two SiO2 structures (monolith and thin film) depends on the porosity of the thin film and yields composite materials with different mechanical stability. By this procedure, capillary microreactors have been prepared and have been proved to be highly active and selective in the total and preferential oxidation of carbon monoxide (TOxCO and PrOxCO).

Adjuvant chemotherapy in rectal cancer: defining subgroups who may benefit after neoadjuvant chemoradiation and resection: a pooled analysis of 3,313 patients

Recent literature suggests that the benefit of adjuvant chemotherapy (aCT) for rectal cancer patients might depend on the response to neoadjuvant chemoradiation (CRT). Aim was to evaluate whether the effect of aCT in rectal cancer is modified by response to CRT and to identify which patients benefit from aCT after CRT, by means of a pooled analysis of individual patient data from 13 datasets. Patients were categorized into three groups: pCR (ypT0N0), ypT1-2 tumour and ypT3-4 tumour. Hazard ratios (HR) for the effect of aCT were derived from multivariable Cox regression analyses. Primary outcome measure was recurrence-free survival (RFS). One thousand seven hundred and twenty three (1723) (52%) of 3,313 included patients received aCT. Eight hundred and ninety eight (898) patients had a pCR, 966 had a ypT1-2 tumour and 1,302 had a ypT3-4 tumour. For 122 patients response, category was missing and 25 patients had ypT0N+. Median follow-up for all patients was 51 (0-219) months. HR for RFS with 95% CI for patients treated with aCT were 1.25(0.68-2.29), 0.58(0.37-0.89) and 0.83(0.66-1.10) for patients with pCR, ypT1-2 and ypT3-4 tumours, respectively. The effect of aCT in rectal cancer patients treated with CRT differs between subgroups. Patients with a pCR after CRT may not benefit from aCT, whereas patients with residual tumour had superior outcomes when aCT was administered. The test for interaction did not reach statistical significance, but the results support further investigation of a more individualized approach to administer aCT after CRT and surgery based on pathologic staging.

Long-term outcome in patients with a pathological complete response after chemoradiation for rectal cancer: a pooled analysis of individual patient data

BACKGROUND

Locally advanced rectal cancer is usually treated with preoperative chemoradiation. After chemoradiation and surgery, 15-27% of the patients have no residual viable tumour at pathological examination, a pathological complete response (pCR). This study established whether patients with pCR have better long-term outcome than do those without pCR.

METHODS

In PubMed, Medline, and Embase we identified 27 articles, based on 17 different datasets, for long-term outcome of patients with and without pCR. 14 investigators agreed to provide individual patient data. All patients underwent chemoradiation and total mesorectal excision. Primary outcome was 5-year disease-free survival. Kaplan-Meier survival functions were computed and hazard ratios (HRs) calculated, with the Cox proportional hazards model. Subgroup analyses were done to test for effect modification by other predicting factors. Interstudy heterogeneity was assessed for disease-free survival and overall survival with forest plots and the Q test.

FINDINGS

484 of 3105 included patients had a pCR. Median follow-up for all patients was 48 months (range 0-277). 5-year crude disease-free survival was 83.3% (95% CI 78.8-87.0) for patients with pCR (61/419 patients had disease recurrence) and 65.6% (63.6-68.0) for those without pCR (747/2263; HR 0.44, 95% CI 0.34-0.57; p<0.0001). The Q test and forest plots did not suggest significant interstudy variation. The adjusted HR for pCR for failure was 0.54 (95% CI 0.40-0.73), indicating that patients with pCR had a significantly increased probability of disease-free survival. The adjusted HR for disease-free survival for administration of adjuvant chemotherapy was 0.91 (95% CI 0.73-1.12). The effect of pCR on disease-free survival was not modified by other prognostic factors.

INTERPRETATION

Patients with pCR after chemoradiation have better long-term outcome than do those without pCR. pCR might be indicative of a prognostically favourable biological tumour profile with less propensity for local or distant recurrence and improved survival.

FUNDING

None.

[Liver metastases from colorectal cancer. Is the practice of surgery based on the best clinical evidence possible?]

To date, surgical resection remains the only curative treatment for liver metastases from colorectal cancer. However, the evidence supporting this treatment is based on retrospective studies. The lack of level I clinical evidence has stimulated strong interest in identifying the factors predictive of recurrence, and even to use them to create clinical risk scores (assigning one point to each factor for poor prognosis), in which a higher score indicates a poorer prognosis. In the present review, we discuss all these factors, as well as the therapeutic alternatives that improve local disease control. Next, we review all the prospective randomized studies published on this topic, which mainly focus on adjuvant chemotherapy associated with curative surgery with negative margins, with the aim of validating or rejecting this treatment. Lastly, we include the algorithm of the University of California at San Francisco for surgery in liver metastases from colorectal cancer.

Mechanisms of microsatellite instability in colorectal cancer patients in different age groups

PURPOSE

The proportion of colorectal cancers located proximal to the splenic flexure increases with age. Colorectal cancers of the microsatellite instability phenotype are preferentially located in the proximal colon. We investigated the location of colorectal cancer with this phenotype in different age groups to determine whether different molecular mechanisms could account for the changes in distribution of colorectal cancers.

METHODS

A representative sample of 230 colorectal cancers from three age groups (<45 years, 60-70 years, >87 years) was selected from a subset of The Upper Midwest Oncology Medical Registries database. Microsatellite instability was determined by polymerase chain reaction using a panel of five microsatellite markers. The presence of new microsatellite alleles at two or more loci was scored as microsatellite instability. Tumors were otherwise considered microsatellite stable. MLH1 and MSH2 expression was determined by immunohistochemistry. Methylation of the MLH1 gene promotor was determined by methylation-specific polymerase chain reaction assay.

RESULTS

The proportion of tumors of the microsatellite instability phenotype was 21 percent in the young group, 15 percent in the middle group, and 33 percent in the old group. More tumors of the microsatellite instability phenotype were proximal compared with microsatellite-stable tumors in all three age groups, but the differences were significant only for the old group. Tumors of the microsatellite instability phenotype in the older group were associated with MLH1 inactivation (24/29 or 83 percent), MLH1 promoter methylation (18/29 or 62 percent), and proximal location (25/29 or 86 percent), while tumors in the young group were associated with MSH2 inactivation (8/18 or 44 percent) and distal location (11/18 or 62 percent).

CONCLUSION

The age-related proximal shift of colorectal cancers is associated with the microsatellite instability phenotype, MLH1 inactivation, and MLH1 promoter hypermethylation.

Endorectal ultrasound in the management of patients with malignant rectal polyps

PURPOSE

This study was designed to determine the efficacy of endorectal ultrasound in the management of patients with malignant rectal polyps removed by snare excision during colonoscopy.

METHODS

A retrospective review of the medical records and endorectal ultrasound images of 63 patients with endoscopically removed rectal polyps containing invasive adenocarcinoma subsequently staged by endorectal ultrasound. Patients underwent surgery or were followed at a single institution. The polyp characteristics and ultrasound images were compared with the presence of residual tumor in the surgical specimen in patients who underwent further surgery or with recurrence in patients who did not.

RESULTS

The morphology of the polyps was described in 31 patients (49 percent); they were sessile in 26 (41 percent) and pedunculated in 6 (9 percent). The margins were positive in 22 patients (35 percent), negative in 19 (30 percent), and not specified in 22 (35 percent). Most tumors were well or moderately differentiated; only 3 (5 percent) were poorly differentiated. Thirty-three patients underwent further surgery (3 low anterior resection, and 30 transanal excision); 30 had no further surgery. The accuracy of endorectal ultrasound in assessing the presence of residual cancer in the rectal wall in patients who had surgery was 54 percent, with a 39 percent positive predictive value and 65 percent negative predictive value. Endorectal ultrasound accurately identified metastatic lymph nodes in two of three patients who had radical surgery. Endorectal ultrasound was more useful than polyp morphologic or histologic criteria to determine the presence of residual cancer in the rectal wall.

CONCLUSIONS

Endorectal ultrasound does not definitely exclude the possibility of residual tumor in the rectal wall or mesenteric nodes of patients who had a malignant polyp snared endoscopically. Consequently, decisions regarding the definitive management of these patients cannot be based exclusively on the endorectal ultrasound images of the polypectomy site.

Evidence of a preferred molecular pathway in patients with synchronous colorectal cancer

BACKGROUND

A small proportion of patients with colorectal carcinoma (CRC) have synchronous tumors at the time of diagnosis. A subset of sporadic CRCs display microsatellite instability (MSI) that is associated with MLH1 silencing due to promoter methylation. In the current study, the authors investigated the proportion of tumors with MSI in patients with synchronous colorectal carcinoma (SCRC) and the concordance in MSI status among tumors in a given individual. In addition, the authors examined MLH1 and MSH2 expression and MLH1 promoter methylation in SCRCs.

METHODS

The current study included 77 patients, with a combined total of 170 invasive SCRCs, who were identified from a database of 2884 patients with CRC. Instability was determined by polymerase chain reaction (PCR) amplification using a set of five markers. Tumors that were unstable at two or more markers were considered unstable (MSI); otherwise, they were considered microsatellite stable (MSS). Expression of MLH1 and MSH2 was determined by immunohistochemistry. Methylation of the MLH1 gene promoter was determined by a methylation-specific PCR assay. Statistical comparisons were made using the chi-square test or the Student t test.

RESULTS

Of the 77 patients in the study, 21 (27%) had a family history of hereditary nonpolyposis colon carcinoma-related malignancy, but none fulfilled the Amsterdam II criteria. Fifty-four of 170 tumors (32%) were found to be MSI. Patients with MSI tumors were older and more frequently female. All but 1 MSI tumor lacked expression of MLH1 (n = 44) or MSH2 (n = 8), or both (n = 1). All MLH1-negative tumors, compared with only 3 MLH1-positive tumors, were methylated at the MLH1 promoter. Most patients (n = 67; 87%) had either all MSS tumors (n = 48; 62%) or all MSI tumors (n = 19; 25%); 10 patients (13%) had both MSS and MSI tumors. The observed MSI/MSS distribution was significantly different from the distribution expected based on an assumption of independence (P < 0.0001).

CONCLUSIONS

There is a strong concordance in MSI/MSS status among tumors in the same individual. This finding suggests that the tumors in patients with SCRC develop along a preferred molecular pathway.

A pathologic complete response to preoperative chemoradiation is associated with lower local recurrence and improved survival in rectal cancer patients treated by mesorectal excision

PURPOSE

Preoperative chemoradiation reduces tumor size and nodal metastasis in patients with rectal cancer. Tumor downstaging has been associated with an increased probability of a sphincter-saving procedure and with improved local control. However, pathologic complete response to chemoradiation has not been correlated with local control and patient survival. We studied the prognostic value of pathologic complete response to preoperative chemoradiation in rectal cancer patients.

METHODS

We have prospectively followed up 168 consecutive patients with ultrasound Stages II (46) and III (122) rectal cancer treated by preoperative chemoradiation followed by radical resection with mesorectal excision; 161 had a curative resection. Recurrence and survival were compared with tumor characteristics and pathologic complete response. Average follow-up was 37 months.

RESULTS

Tumor downstaging occurred in 97 (58 percent) patients, including 21 (13 percent) patients who had a pathologic complete response. None of the clinical or pathologic variables was associated with pathologic complete response. The estimated 5-year rate of local recurrence was 5 percent; of distant metastasis, 14 percent. None of the patients with pathologic complete response has developed disease recurrence. We found no difference in survival among patients with pathologic Stages I, II, or III tumors.

CONCLUSIONS

A pathologic complete response to preoperative chemoradiation is associated with improved local control and patient survival. For patients without pathologic complete response, the pathology stage does not have prognostic significance.

Patient satisfaction after surgical treatment for fistula-in-ano

PURPOSE

The surgical treatment of fistula-in-ano frequently results in recurrence of the fistula or postoperative anal incontinence. Despite these problems, most patients are satisfied with the results of their surgery. To clarify this apparent discrepancy, we attempted to identify factors that affect patient's lifestyles and may contribute to their satisfaction.

METHODS

A questionnaire was mailed to 624 patients surgically treated for cryptoglandular fistula-in-ano at the University of Minnesota during a five-year period. Three hundred seventy-five patients returned their questionnaires. Patients who were followed up for a minimum of one year were included in this retrospective study. Associations between postoperative complications and patient satisfaction were identified by chi-squared tests and multiple logistic regression. Attributable fractions for patient dissatisfaction were calculated using study population dissatisfaction rates.

RESULTS

Patient satisfaction was strongly associated with fistula recurrence, difficulty holding gas, soiling of undergarment, and accidental bowel movements. Effects of incontinence on patient quality of life were also significantly associated with patient satisfaction as was the number of lifestyle activities affected by incontinence. Patients with fistula recurrence reported a higher dissatisfaction rate (61 percent) than did patients with anal incontinence (24 percent), but the attributable fraction of dissatisfaction for incontinence (84 percent) was greater than that for fistula recurrence (33 percent). Patient satisfaction was not significantly associated with age, gender, history of previous fistula surgery, type of fistula, surgical procedure, time since surgery, or operating surgeon.

CONCLUSION

Patient satisfaction after surgical treatment for fistula-in-ano is associated with recurrence of the fistula, the development of anal incontinence, and with the effects of anal incontinence on patient lifestyle. In our series of patients treated mainly with laying open of the fistula tract, patients with fistula recurrence had a higher dissatisfaction rate than did patients with anal incontinence. However, because anal incontinence was more prevalent than fistula recurrence, a higher fraction of dissatisfaction was attributable to anal incontinence.

Is local excision adequate therapy for early rectal cancer?

PURPOSE

Radical surgery of rectal cancer is associated with significant morbidity, and some patients with low-lying lesions must accept a permanent colostomy. Several studies have suggested satisfactory tumor control after local excision of early rectal cancer. The purpose of this study was to compare recurrence and survival rates after treating early rectal cancers with local excision and radical surgery.

METHODS

One hundred eight patients with T1 and T2 rectal adenocarcinomas treated by transanal excision were compared with 153 patients with T1N0 and T2N0 rectal adenocarcinomas treated with radical surgery. Neither group received adjuvant chemoradiation. Mean follow-up time was 4.4 years after local excision and 4.8 years after radical surgery.

RESULTS

The estimated five-year local recurrence rate was 28 percent (18 percent for T1 tumors and 47 percent for T2 tumors) after local excision and 4 percent (none for T1 tumors and 6 percent for T2 tumors) after radical surgery. Overall recurrence was also higher after local excision (21 percent for T1 tumors and 47 percent for T2 tumors) than after radical surgery (9 percent for T1 tumors and 16 percent for T2 tumors). Twenty-four of 27 patients with recurrence after local excision underwent salvage surgery. The estimated five-year overall survival rate was 69 percent after local excision (72 percent for T1 tumors and 65 percent after T2 tumors) and 82 percent after radical surgery (80 percent for T1 tumors and 81 percent for T2 tumors). Differences in survival rate between local excision and radical surgery were statistically significant in patients with T2 tumors.

CONCLUSIONS

Local excision of early rectal cancer carries a high risk of local recurrence. Salvage surgery is possible in most patients with local recurrence, but may be effective only in patients with T1 tumors. When compared with radical surgery, local excision may compromise overall survival in patients with T2 rectal cancers.

Modification of the gluteal perforator-based flap for reconstruction of the posterior vagina

Vaginal reconstruction after pelvic exenteration not only affords significant psychological benefit, it also decreases the morbidity and mortality associated with pelvic exenteration. In irradiated patients filling the surgical defect with healthy, well-vascularized tissue, such as omental flaps, colonic advancements, and myocutaneous flaps, has been shown to decrease the incidence of fistulas, bowel obstructions, infections, and hemorrhage. A novel use of the gluteal perforator-based flap is described in the unique circumstance of posterior pelvic exenteration with sacrectomy.

Incontinence after lateral internal sphincterotomy: anatomic and functional evaluation

PURPOSE

This study was designed to evaluate the anatomic and functional consequences of lateral internal sphincterotomy in patients who developed anal incontinence and in matched controls.

METHODS

The study includes 13 patients with anal incontinence after lateral internal sphincterotomy and 13 controls who underwent the same operation and were continent and satisfied with the results of the procedure. Patients underwent clinical evaluation, anorectal manometry, pudendal nerve terminal motor latency testing, and endoanal ultrasonography.

RESULTS

Sphincterotomies were longer in incontinent patients (75 vs. 57 percent), but the resting pressure and length of the high-pressure zone were not different between groups. Surprisingly, maximum voluntary contraction was higher in incontinent patients than in continent controls (136 vs. 100 mmHg). Rectal sensation and pudendal nerve terminal motor latency were similar in both groups. The defect in the internal sphincter was wider in incontinent patients than in continent controls (17.3 vs. 14.4 mm), but these differences were not statistically significant. The thickness of the internal sphincter measured by endoanal ultrasound was identical in both groups, but the external sphincter was thinner in incontinent patients both at the site of the sphincterotomy (6.8 vs. 8.1 mm) and in the posterior midline (7.1 vs. 8.6 mm).

CONCLUSIONS

Anal incontinence after lateral internal sphincterotomy is directly related to the length of the sphincterotomy. Whether secondary to preoperative sphincter abnormality or the result of lateral internal sphincterotomy, the external sphincter is thinner in incontinent patients than in continent controls.

Cutting seton versus two-stage seton fistulotomy in the surgical management of high anal fistula

BACKGROUND

The aim of this study was to compare the clinical results obtained with the cutting seton and the two-stage seton fistulotomy (TSSF) in the surgical management of high anal fistula.

METHODS

The case records of 59 patients with high anal fistula of cryptoglandular origin treated with cutting seton (n = 12) or TSSF (n = 47) over a 5-year period were retrospectively reviewed. There was no difference between the groups in age, sex distribution, or estimated percentage of anal sphincter involved by the fistula. Follow-up was by a mailed questionnaire inquiring about fistula recurrence, incontinence, and degree of satisfaction. Mean follow-up was similar in both groups (27 months for cutting seton versus 33 months for TSSF). Comparisons were made by Student t and chi 2 tests, as required.

RESULTS

There were no differences in the rate of fistula recurrence between the groups treated with cutting seton or TSSF (one of 12 versus four of 47), difficulty holding gas (six of 12 versus 25 of 47), underwear staining (six of 12 versus 18 of 47), stool incontinence (three of 12 versus 12 of 27), overall incontinence (eight of 12 versus 31 of 47) and mean incontinence score (4.9 versus 4.2). The fistula healing time and degree of satisfaction with the operation were not significantly different between the groups. One-half of the patients treated by TSSF had the seton removed under general or epidural anaesthesia.

CONCLUSION

Both techniques are equally effective in eradicating the fistula, and both are associated with a similar rate of incontinence.

[Necrotizing gastroenteritis associated with inflammatory bowel disease]

Gangrene of the stomach is a rare and catastrophic event, usually attributed to local pathologic conditions. Although there are no cases documented in the literature, non-occlusive arterial ischemia is sometimes listed among the causes of necrotizing gastritis. We report a case of necrotizing gastroenteritis associated with a low flow state secondary to an episode of fulminant colitis, fecal peritonitis and septic shock. The patient recovered after staged resection of the involved segments of the gastrointestinal tract.

Characterization of the p150,95 leukocyte integrin alpha subunit (CD11c) gene promoter. Identification of cis-acting elements

The leukocyte integrin p150,95 (CD11c/CD18) is involved in a number of cell-cell and cell-extracellular matrix interactions and mediates signal transduction into the cytoplasm. p150,95 is expressed on cells of the myeloid lineage as well as on certain activated T and B lymphocytes, and its expression is regulated during cell activation and differentiation. Since CD18 is expressed on all leukocyte lineages, the restricted expression of p150,95 must be controlled at the level of CD11c gene transcription. To understand the mechanisms that direct the constitutive and regulated leukocyte expression of p150,95 we have structurally characterized the CD11c promoter region and initiated its functional dissection. The CD11c promoter lacks TATA- and CCAAT-boxes, directs the synthesis of transcripts with heterogeneous 5'-ends, and contains an initiator-like sequence at the major transcription initiation site. Several putative binding sequences for ubiquitous (Sp1, AP-1, AP-2, and NF-kB) and leukocyte-specific (PU.1) transcription factors have been identified in the proximal region of the CD11c promoter which may participate in the regulation of the expression of p150,95. Transient expression of CD11c-based reporter gene constructs indicates that the CD11c promoter dictates the tissue-specific expression of p150,95 and that sequences contained within 160 base pairs 5' from the major transcriptional start site are involved in the tissue-specific and regulated expression of p150,95. DNase I protection analysis on the promoter region spanning from -160 to +40 revealed four regions of DNA-protein interactions (FPI-FPIV), two of which (FPII and FPIV) correlate with the cell type-specific and regulated expression of the CD11c gene.