ALLIANCE A022104/NRG-GI010: The Janus Rectal Cancer Trial: a randomized phase II/III trial testing the efficacy of triplet versus doublet chemotherapy regarding clinical complete response and disease-free survival in patients with locally advanced rectal cancer

Background

Recent data have demonstrated that in locally advanced rectal cancer (LARC), a total neoadjuvant therapy (TNT) approach improves compliance with chemotherapy and increases rates of tumor response compared to neoadjuvant chemoradiation (CRT) alone. They further indicate that the optimal sequencing of TNT involves consolidation (rather than induction) chemotherapy to optimize complete response rates. Data, largely from retrospective studies, have also shown that patients with clinical complete response (cCR) after neoadjuvant therapy may be managed safely with the watch and wait approach (WW) instead of preemptive total mesorectal resection (TME). However, the optimal consolidation chemotherapy regimen to achieve cCR has not been established, and a randomized clinical trial has not robustly evaluated cCR as a primary endpoint. Collaborating with a multidisciplinary oncology team and patient groups, we designed this NCI-sponsored study of chemotherapy intensification to address these issues and to drive up cCR rates, to provide opportunity for organ preservation, improve quality of life for patients and improve survival outcomes.

Methods

In this NCI-sponsored multi-group randomized, seamless phase II/III trial (1:1), up to 760 patients with LARC, T4N0, any T with node positive disease (any T, N+) or T3N0 requiring abdominoperineal resection or coloanal anastomosis and distal margin within 12 cm of anal verge will be enrolled. Stratification factors include tumor stage (T4 vs T1-3), nodal stage (N+ vs N0) and distance from anal verge (0-4; 4-8; 8-12 cm). Patients will be randomized to receive neoadjuvant long course chemoradiation (LCRT) followed by consolidation doublet (mFOLFOX6 or CAPOX) or triplet chemotherapy (mFOLFIRINOX) for 3-4 months. LCRT in both arms involves 4500 cGy in 25 fractions over 5 weeks + 900 cGy boost in 5 fractions with a fluoropyrimidine (capecitabine preferred). Patients will undergo assessment 8-12 (+/- 4) weeks post-TNT completion. The primary endpoint for the phase II portion will compare cCR between treatment arms. A total number of 296 evaluable patients (148 per arm) will provide statistical power of 90.5% to detect an 17% increase in cCR rate, at a one-sided alpha=0.048. The primary endpoint for the phase III portion will compare disease-free survival (DFS) between treatment arms. A total of 285 DFS events will provide 85% power to detect an effect size of hazard ratio 0.70 at a one-sided alpha of 0.025, requiring enrollment of 760 patients (380 per arm). Secondary objectives include time-to event outcomes (overall survival, organ preservation time and time to distant metastasis) and adverse effects. Biospecimens including archival tumor tissue, plasma and buffy coat in EDTA tubes, and serial rectal MRIs will be collected for exploratory correlative research. This study, activated in late 2022, is open across the NCTN and has a current accrual of 312. Support: U10CA180821, U10CA180882, U24 CA196171; https://acknowledgments.alliancefound.org .

Discussion

Building off of data from modern day rectal cancer trials and patient input from national advocacy groups, we have designed the current trial studying chemotherapy intensification via a consolidation chemotherapy approach with the intent to enhance cCR and DFS rates, increase organ preservation rates, and improve quality of life for patients with rectal cancer.

Trial Registration

Clinicaltrials.gov ID: NCT05610163 ; Support includes U10CA180868 (NRG) and U10CA180888 (SWOG).

Progressive plasticity during colorectal cancer metastasis

Metastasis is the principal cause of cancer death, yet we lack an understanding of metastatic cell states, their relationship to primary tumor states, and the mechanisms by which they transition. In a cohort of biospecimen trios from same-patient normal colon, primary and metastatic colorectal cancer, we show that while primary tumors largely adopt LGR5 + intestinal stem-like states, metastases display progressive plasticity. Loss of intestinal cell states is accompanied by reprogramming into a highly conserved fetal progenitor state, followed by non-canonical differentiation into divergent squamous and neuroendocrine-like states, which is exacerbated by chemotherapy and associated with poor patient survival. Using matched patient-derived organoids, we demonstrate that metastatic cancer cells exhibit greater cell-autonomous multilineage differentiation potential in response to microenvironment cues than their intestinal lineage-restricted primary tumor counterparts. We identify PROX1 as a stabilizer of intestinal lineage in the fetal progenitor state, whose downregulation licenses non-canonical reprogramming.

Prevalence of nodal involvement in rectal cancer after chemoradiotherapy

BACKGROUND

The purpose of this study was to investigate the prevalence of ypN+ status according to ypT category in patients with locally advanced rectal cancer treated with chemoradiotherapy and total mesorectal excision, and to assess the impact of ypN+ on disease recurrence and survival by pooled analysis of individual-patient data.

METHODS

Individual-patient data from 10 studies of chemoradiotherapy for rectal cancer were included. Pooled rates of ypN+ disease were calculated with 95 per cent confidence interval for each ypT category. Kaplan-Meier and Cox regression analyses were undertaken to assess influence of ypN status on 5-year disease-free survival (DFS) and overall survival (OS).

RESULTS

Data on 1898 patients were included in the study. Median follow-up was 50 (range 0-219) months. The pooled rate of ypN+ disease was 7 per cent for ypT0, 12 per cent for ypT1, 17 per cent for ypT2, 40 per cent for ypT3, and 46 per cent for ypT4 tumours. Patients with ypN+ disease had lower 5-year DFS and OS (46.2 and 63.4 per cent respectively) than patients with ypN0 tumours (74.5 and 83.2 per cent) (P < 0.001). Cox regression analyses showed ypN+ status to be an independent predictor of recurrence and death.

CONCLUSION

Risk of nodal metastases (ypN+) after chemoradiotherapy increases with advancing ypT category and needs to be considered if an organ-preserving strategy is contemplated.

Rectal cancer lateral lymph nodes: multicentre study of the impact of obturator and internal iliac nodes on oncological outcomes

BACKGROUND

In patients with rectal cancer, enlarged lateral lymph nodes (LLNs) result in increased lateral local recurrence (LLR) and lower cancer-specific survival (CSS) rates, which can be improved with (chemo)radiotherapy ((C)RT) and LLN dissection (LLND). This study investigated whether different LLN locations affect oncological outcomes.

METHODS

Patients with low cT3-4 rectal cancer without synchronous distant metastases were included in this multicentre retrospective cohort study. All MRI was re-evaluated, with special attention to LLN involvement and response.

RESULTS

More advanced cT and cN category were associated with the occurrence of enlarged obturator nodes. Multivariable analyses showed that a node in the internal iliac compartment with a short-axis (SA) size of at least 7 mm on baseline MRI and over 4 mm after (C)RT was predictive of LLR, compared with a post-(C)RT SA of 4 mm or less (hazard ratio (HR) 5.74, 95 per cent c.i. 2.98 to 11.05 vs HR 1.40, 0.19 to 10.20; P < 0.001). Obturator LLNs with a SA larger than 6 mm after (C)RT were associated with a higher 5-year distant metastasis rate and lowered CSS in patients who did not undergo LLND. The survival difference was not present after LLND. Multivariable analyses found that only cT category (HR 2.22, 1.07 to 4.64; P = 0.033) and margin involvement (HR 2.95, 1.18 to 7.37; P = 0.021) independently predicted the development of metastatic disease.

CONCLUSION

Internal iliac LLN enlargement is associated with an increased LLR rate, whereas obturator nodes are associated with more advanced disease with increased distant metastasis and reduced CSS rates. LLND improves local control in persistent internal iliac nodes, and might have a role in controlling systemic spread in persistent obturator nodes.Members of the Lateral Node Study Consortium are co-authors of this study and are listed under the heading Collaborators.

Changes in the multidisciplinary management of rectal cancer from 2009 to 2015 and associated improvements in short-term outcomes

AIM

Significant recent changes in management of locally advanced rectal cancer (LARC) include preoperative staging, use of extended neoadjuvant therapies and minimally invasive surgery (MIS). This study was aimed at characterizing these changes and associated short-term outcomes.

METHOD

We retrospectively analysed treatment and outcome data from patients with T3/4 or N+ LARC ≤ 15 cm from the anal verge who were evaluated at a comprehensive cancer centre in 2009-2015.

RESULTS

In total, 798 patients were identified and grouped into five cohorts based on treatment year: 2009-2010, 2011, 2012, 2013 and 2014-2015. Temporal changes included increased reliance on MRI staging, from 57% in 2009-2010 to 98% in 2014-2015 (P < 0.001); increased use of total neoadjuvant therapy, from 17% to 76% (P < 0.001); and increased use of MIS, from 33% to 70% (P < 0.001). Concurrently, median hospital stay decreased (from 7 to 5 days; P < 0.001), as did the rates of Grade III-V complications (from 13% to 7%; P < 0.05), surgical site infections (from 24% to 8%; P < 0.001), anastomotic leak (from 11% to 3%; P < 0.05) and positive circumferential resection margin (from 9% to 4%; P < 0.05). TNM downstaging increased from 62% to 74% (P = 0.002).

CONCLUSION

Shifts toward MRI-based staging, total neoadjuvant therapy and MIS occurred between 2009 and 2015. Over the same period, treatment responses improved, and lengths of stay and the incidence of complications decreased.

Effectiveness of a multidisciplinary patient care bundle for reducing surgical-site infections

BACKGROUND

Surgical-site infection (SSI) is associated with significant healthcare costs. To reduce the high rate of SSI among patients undergoing colorectal surgery at a cancer centre, a comprehensive care bundle was implemented and its efficacy tested.

METHODS

A pragmatic study involving three phases (baseline, implementation and sustainability) was conducted on patients treated consecutively between 2013 and 2016. The intervention included 13 components related to: bowel preparation; oral and intravenous antibiotic selection and administration; skin preparation, disinfection and hygiene; maintenance of normothermia during surgery; and use of clean instruments for closure. SSI risk was evaluated by means of a preoperative calculator, and effectiveness was assessed using interrupted time-series regression.

RESULTS

In a population with a mean BMI of 30 kg/m² , diabetes mellitus in 17·5 per cent, and smoking history in 49·3 per cent, SSI rates declined from 11·0 to 4·1 per cent following implementation of the intervention bundle (P = 0·001). The greatest reductions in SSI rates occurred in patients at intermediate or high risk of SSI: from 10·3 to 4·7 per cent (P = 0·006) and from 19 to 2 per cent (P < 0·001) respectively. Wound care modifications were very different in the implementation phase (43·2 versus 24·9 per cent baseline), including use of an overlying surface vacuum dressing (17·2 from 1·4 per cent baseline) or leaving wounds partially open (13·2 from 6·7 per cent baseline). As a result, the biggest difference was in wound-related rather than organ-space SSI. The median length of hospital stay decreased from 7 (i.q.r. 5-10) to 6 (5-9) days (P = 0·002). The greatest reduction in hospital stay was seen in patients at high risk of SSI: from 8 to 6 days (P < 0·001). SSI rates remained low (4·5 per cent) in the sustainability phase.

CONCLUSION

Meaningful reductions in SSI can be achieved by implementing a multidisciplinary care bundle at a hospital-wide level.

Incisional hernias after laparoscopic and robotic right colectomy

PURPOSE

Incisional hernia (IH) is a common complication after colectomy, with impacts on both health care utilization and quality of life. The true incidence of IH after minimally invasive colectomy is not well described. The purpose of this study was to examine IH incidence after minimally invasive right colectomies (RC) and to compare the IH rates after laparoscopic (L-RC) and robotic (R-RC) colectomies.

METHODS

This is a retrospective review of patients undergoing minimally invasive RC at a single institution from 2009 to 2014. Only patients undergoing RC for colonic neoplasia were included. Patients with previous colectomy or intraperitoneal chemotherapy were excluded. Three L-RC patients were included for each R-RC patient. The primary outcome was IH rate based on clinical examination or computed tomography (CT). Univariate and multivariate time-to-event analyses were used to assess predictors of IH.

RESULTS

276 patients where included, of which 69 had undergone R-RC and 207 L-RC. Patient and tumor characteristics were similar between the groups, except for higher tumor stage in L-RC patients. Both the median time to diagnosis (9.2 months) and the overall IH rate were similar between the groups (17.4 % for R-RC and 22.2 % for L-RC), as were all other postoperative complications. In multivariable analyses, the only significant predictor of IH was former or current tobacco use (hazard raio 3.0, p = 0.03).

CONCLUSIONS

This study suggests that the incidence of IH is high after minimally invasive colectomy and that this rate is equivalent after R-RC and L-RC. Reducing the IH rate represents an important opportunity for improving quality of life and reducing health care utilization after minimally invasive colectomy.

The extent of lymphadenectomy and overall survival depend on the timing of radiotherapy for rectal cancer

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Background: Accurate staging and local disease control depend on the extent of lymphadenectomy (LAD) in rectal cancer. Previous studies suggest that lymph node (LN) number varies with neoadjuvant therapies. Our objectives were to measure the impact of timing of radiotherapy on extent of LAD and to determine the prognostic role of LN number in rectal cancer.

Methods: Patients undergoing curative-intent surgery for rectal adenocarcinoma (1988-2006) in Los Angeles County were identified from the Cancer Surveillance Program. Patients were grouped according to radiotherapy timing (neoadjuvant, adjuvant, or none). To measure prognostic significance, an optimal cutoff was assessed for patients with N0 disease by dichotomizing LN numbers from 3-7.

Results: Query of the registry identified 6,358 patients. Of these, 20% (n = 1,280), 25% (n = 1,573), and 55% (n = 3,545) received neoadjuvant, adjuvant, and no radiotherapy, respectively. There was no difference in LN number in patients with and without radiotherapy (7 vs. 8 LNs, p = NS). However, within the radiotherapy cohort, there was significantly lower LNs in the neoadjuvant group (5 vs. 9 LNs, respectively; p < 0.001). Survival differences favored the groups with higher LN number. The optimal LN cutoff with no survival difference was 7 in the adjuvant radiotherapy group; there was no optimal cutoff for neoadjuvant therapy patients.

Conclusions: From our population-based cohort, we observed that patients receiving neoadjuvant radiotherapy had decreased LN retrieval and that LN number was non-prognostic. In contrast, the extent of LAD is a prognostic factor for overall survival in patients receiving adjuvant radiotherapy.

[Table: see text]

No significant financial relationships to disclose.

Differential expression of small ubiquitin-like modifier family of proteins in patients with colorectal adenocarcinoma

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Background: The cytotoxic effects of radiation and chemotherapy are mediated in part by DNA damage. The small ubiquitin-like modifier (SUMO) family of proteins regulates DNA repair pathways by activating factors involved in homologous recombination (HR) or non- homologous end joining (NHEJ). Our objective was to determine the potential role of SUMO proteins in patients with colorectal cancer.

Methods: We first assessed two established colorectal cancer cell lines (HCT116 and HT29) and two normal colonic mucosa cell populations utilizing ultra high-throughput expression analysis (Solexa) to examine differential expression of genes involved in SUMOylation (SAE1, SAE2, PIAS-1, and DNAPKcs). To verify the clinical relevance of SUMOylation in colorectal cancer, we obtained archived specimens from patients with colorectal cancer (n=51) and examined the expression of these proteins in both benign and malignant tissue by immunohistochemistry (IHC).

Results: Ultra high-throughput expression analysis of cancer and normal cells revealed a 10 to 15-fold upregulation of SAE2 (heterodimer of the E1 activation enzyme in SUMOylation), a 10 to 11-fold upregulation of DNAPKcs (catalytic subunit in NHEJ repair pathway), and a 6-fold upregulation of SAE1 in cancer cells. In contrast, PIAS-1 showed similar expression levels between cancer and normal colonic cells. By IHC, SAE1 and SAE2 were highly expressed in 65% and 53% of tumor specimens, respectively; but only in 7% and 0% of normal tissues, respectively. DNAPKcs was also highly expressed in tumor tissues (63%) with corresponding low expression (0%) in normal tissues. Corroborating the cell line results, PIAS-1 was infrequently expressed in both tumor (10%) and normal tissues (0%).

Conclusions: We are the first to demonstrate the differential expression of SUMO proteins in colorectal cancer cell lines and in clinical specimens. SUMO proteins have a role in DNA repair and their expression in colorectal cancer may modify tumor response to chemoradiotherapy.

No significant financial relationships to disclose.

Evaluation of response after chemoradiation for rectal cancer as a predictive factor for the benefit of adjuvant chemotherapy: A pooled analysis of 2,724 individual patients

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Background: Neoadjuvant chemoradiation (CRT) for rectal cancer increasingly results in pathologic response. It has been suggested that patients with different degrees of response might not have the same benefit of adjuvant chemotherapy. The aim was to determine whether patients with a pathologic complete response (pCR), ypT1-2 or ypT3-4 tumor after CRT for rectal cancer have different benefits of adjuvant chemotherapy for disease-free survival.

Methods: Authors from studies evaluating different degrees of response to CRT were contacted to share individual patient data. The collected individual patient data were pooled into one dataset. To evaluate the effect of adjuvant chemotherapy on disease-free survival multivariate analyses according to the Cox proportional hazards model were performed. Hazard ratios (HR) with 95% confidence intervals (CI) were calculated for 3 subgroups: patients with pCR(ypT0N0), ypT1-2 tumor and ypT3-4 tumor after CRT. To determine benefit of adjuvant chemo for different pathologic N-stages we performed subgroup analyses.

Results: 2,724 patients were included. 811 had pCR (28%), 863 had ypT1-2 (30%) and 1050 had ypT3-4 (37%). Median follow-up was 50 months (range 0-277). 41% underwent adjuvant chemotherapy, which consisted mostly of 5-FU based chemotherapy. The HR with 95%CI for disease-free survival for adjuvant chemotherapy was 0.94 (0.50-1.78) for patients with pCR, 0.61 (0.40-0.92) for patients with ypT1-2 tumors and 0.97 (0.75-1.25) for patients with ypT3-4 tumors. ypT1-2N0 patients benefited most from adjuvant chemo: HR 0.45 (0.27-0.75) vs. 0.79 (0.31-1.95) for patients with ypT1-2N+. For ypT3-4 patients pN-stage did not alter benefit of adjuvant chemo.

Conclusions: Patients with pCR or ypT3-4 residual tumor after CRT do not seem to benefit from adjuvant chemo. This might be due to the already good prognosis of patients with pCR and less responsiveness to 5-FU based chemotherapy in the poor responders (the ypT3-4 tumors). Possibly adjuvant chemotherapy can be omitted or adapted for these patients. Patients with ypT1-2N0 benefit most from adjuvant chemo.

No significant financial relationships to disclose.

Use of the XRCC1 single nucleotide polymorphism to predict pathologic complete response to neoadjuvant chemoradiation in stage II/III rectal cancer

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Background: The X-ray repair cross-complementing protein 1 (XRCC1) gene plays an important role in DNA damage repair; and the R194W and R399Q single nucleotide polymorphisms (SNPs) are associated with attenuated DNA repair activity. Our objective was to determine whether XRCC1 SNPs were associated with response to neoadjuvant chemoradiation therapy (CRT) in rectal cancer patients.

Methods: We conducted a prospective multicenter phase II trial to investigate the effect of additional chemotherapy with a longer CRT-to-surgery interval on treatment response in patients with rectal cancer. Paired normal and rectal cancer tissues were prospectively collected from enrolled patients (n=110). DNA was extracted from normal rectal mucosa and analyzed for XRCC1 R194W and R399Q by polymerase chain reaction and sequencing. Each SNP was compared to response to CRT. Response to CRT was determined by a central pathologist.

Results: Of the 110 patients, 25% (n=27) achieved a pathologic complete response (pCR). We examined the XRCC1 R194W SNP and observed that the allelic frequency of patients with the R/R genotype was 84% (n=92), the R/W genotype was 14% (n=16), the W/W genotype was 1% (n=2). By Fisher's Exact test, patients harboring either the R/W or W/W genotype, had a significantly higher rate of pCR compared to patients with the R/R genotype (44% vs. 21%, respectively; p=0.04). We then examined the R399Q SNP and observed that the allelic frequency of patients with the R/R genotype was 34% (n=37), the R/Q genotype was 49% (n=54), and the Q/Q genotype was 17% (n=19). In contrast, the detection of XRCC1 R399Q SNPs was not associated with pCR.

Conclusions: We demonstrate that XRCC1 R194W SNP is associated with increased rate of pCR in our prospective multi-center trial. Although the detection of XRCC1 R399Q SNP is not associated with pCR, the detection of XRCC1 SNPs that predict treatment response may help identify patients who are unlikely to respond to CRT and therefore may potentially avoid treatment-associated morbidities.

No significant financial relationships to disclose.

Use of genetic variations to predict toxicity associated with neoadjuvant chemoradiation for AJCC stage II/III rectal cancer

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Background: Genetic polymorphisms have been associated with toxicity from chemotherapeutic agents for colon cancer, but none has been identified for rectal cancer. We examined the association between polymorphisms in genes for DNA repair, cell cycle progression, angiogenesis, and drug metabolism with toxicity from neoadjuvant chemoradiation treatment (CRT) for rectal cancer.

Methods: Patients with AJCC stage II/III rectal adenocarcinoma were enrolled in a phase II multicenter trial examining timing of rectal cancer response to neoadjuvant CRT. There were two treatment arms: (I) radiation (XRT) and 5-FU followed by surgery and (II) XRT/5-FU and FOLFOX followed by surgery. Treatment toxicity, classified by the NCI Common Terminology Criteria guidelines as grade 3 and above, was recorded. DNA was extracted from normal rectal mucosa and analyzed for 22 polymorphisms in 17 genes.

Results: We evaluated 110 patients (group I, n = 52; group II, n = 58). A total of 19 patients experienced grade 3+ adverse events (AE) [group I, n = 10 (19%); group II, n = 9 (16%)]. Gastrointestinal symptoms were the most common AE [group I, n = 5 (10%); group II, n = 4 (7%)]. The detection of lys allele (lys/lys or lys/gln genotypes) at codon 751 of the Xeroderma pigmentosum group D (XPD) gene was associated with increased toxicity in group II (p = 0.03), whereas homozygosity for the arg allele (i.e., arg/arg genotype) at codon 399 of the X-ray cross-complementing protein 1 (XRCC1) gene was associated with a significant increase in toxicity in both treatment groups (p = 0.009).

Conclusions: Genetic polymorphisms in DNA damage repair genes XPD and XRCC1 are associated with toxicity in rectal cancer patients receiving CRT. The identification of gene polymorphisms that predict adverse events may help to optimize patient therapy while minimizing morbidities.

No significant financial relationships to disclose.

Aetiology and surgical management of toxic megacolon

OBJECTIVE

The purpose of this article is to review the surgical management and outcome of toxic megacolon and to update the aetiology of toxic megacolon.

PATIENTS AND METHOD

A retrospective chart review of three academic colorectal surgery units was undertaken. Over a period of 20 years, 70 patients with surgically managed toxic megacolon were identified: 32 men and 38 women, median age 63 years (range, 23-87 years).

RESULTS

In 33 (48%) patients the main cause of toxic megacolon was inflammatory bowel disease. Thirty-seven (52%) patients had toxic megacolon of different aetiology. Sixty-three patients underwent colonic resection: 49 (70%) subtotal colectomies and 14 (20%) total colectomies, including 4 (6%) proctocolectomies. Seven (10%) patients had decompression (n=3) or faecal diversion (n=4) only. Forty-four of the resected patients underwent a Hartmann's procedure and an ileostomy; 13 (19%) patients had primary anastomoses, 11 (16%) ileorectal anastomoses (IRA) and 2 (3%) patients had ileal pouch-anal anastomosis (IPAA). Twenty-six (37%) patients subsequently had continuity restored. Total surgical complication rate was 19% (n=13), 8% (n=4) in patients treated with subtotal colectomy, 21% (n=3) in patients treated with total proctocolectomy and 86% (n=6) in patients treated with either decompression or diversion. The total mortality rate was 16% (n=11).

CONCLUSIONS

Toxic colitis complicated by toxic megacolon can occur after various diseases of the colon and remains a life-threatening disorder associated with a significant risk of postoperative complications. Subtotal colectomy with ileostomy remains the procedure of choice. Surgical colonic decompression with faecal diversion alone is associated with a high rate of complications.

Interobserver variability in the pathological assessment of malignant colorectal polyps

Background

Treatment of patients with malignant large bowel polyps is highly dependent on pathological evaluation. The aim of this study was to evaluate interobserver variability in the pathological assessment of endoscopically removed polyps.

Methods

The records of 88 patients with colorectal cancer who underwent endoscopic removal of malignant polyps were reviewed. Study investigators reviewed the initial pathology report; three experienced gastrointestinal pathologists reviewed all slides in a blinded fashion. Interobserver variability of pathological assessment of malignant polyps was analysed by κ statistics.

Results

Seventy-six (86 per cent) of the 88 patients had malignant polyps and 12 (14 per cent) had carcinoma in situ. Agreement between experienced pathologists was substantial with regard to T stage (κ = 0·725), resection margin status (κ = 0·668) and Haggitt's classification (κ = 0·682), but comparison of initial and experienced pathologists' assessment demonstrated only moderate agreement in these areas (κ = 0·516, κ = 0·555 and κ = 0·578 respectively). Agreement between even experienced pathologists was poor with respect to histological grade of differentiated adenocarcinomas (κ = 0·163) and angiolymphatic vessel invasion (κ = − 0·017).

Conclusion

Pathological assessment of malignant polyps varies between observers. Specialist pathologists appear to have a higher degree of consensus among themselves than with generalist pathologists with respect to T stage. The high interobserver variability with regard to histological grade of differentiated tumours is clinically irrelevant. However, variability in the assessment of angiolymphatic vessel invasion limits the value of this measurement for clinical decision making.

Treatment of locally recurrent rectal cancer

PURPOSE

This study was designed to analyze the outcome for patients with isolated local recurrence after radical treatment of rectal cancer and to identify predictors of curative resection.

METHODS

The medical records of 87 patients who developed isolated local recurrence after curative radical surgery for primary rectal cancer were retrospectively reviewed. Survival rates from the time of recurrence were calculated using the Kaplan-Meier method. Tumor stage and histology, patient characteristics, and treatment variables were analyzed using logistic regression to identify predictors of curative surgery.

RESULTS

Symptomatic treatment alone or chemotherapy and/or radiation therapy was provided to 23 patients (26 percent), and surgical exploration was performed in 64 patients. In 22 patients (25 percent), the tumor was considered unresectable at surgery (n = 13) or was resected for palliation with gross or microscopic positive margins (n = 9). In 42 patients (48 percent), curative-intent resection was performed. The only independent predictors of resectability were younger age at diagnosis, earlier stage of the primary tumor, and initial treatment by sphincter-saving procedure. There was no difference in survival between patients who had no surgery and those who had palliative surgery. The estimated five-year survival rate for patients who had curative-intent resection was better than for those who had no surgery or palliative surgery (35 vs. 7 percent; P = 0.01). Of the 42 patients who underwent curative-intent resection, 14 (33 percent) developed a second recurrence at a mean of 15 +/- 11 months after reoperation. Twenty-five percent of patients developed major complications.

CONCLUSIONS

Salvage surgery for locally recurrent rectal cancer may be helpful in a selected group of patients. The stage and treatment of the primary tumor may help to identify patients with the best chance for curative-intent resection.

Pelvic wall involvement denotes a poor prognosis in T4 rectal cancer

PURPOSE

An aggressive surgical approach with en bloc resection of involved structures is often possible with anterior rectal cancers that invade adjacent visceral organs, but is rarely possible in tumors that invade the pelvic wall. However, most staging systems include both situations in the same group of T4 rectal cancers. We performed a retrospective study of patients with stage T4 rectal cancer undergoing surgery to assess the influence of different organ involvement on resectability and survival.

METHODS

A retrospective review was conducted of 84 patients with T4 rectal cancer treated at the University of Minnesota and affiliated hospitals over a ten-year period. Forty-seven patients (56 percent) were staged for local invasion on the basis of final pathology, 19 (23 percent) on the basis of operative findings, and 18 (21 percent) on the basis of ultrasound images. Patients were divided into two groups, those with or without pelvic wall involvement. Resectability, local control, and overall survival were compared between groups. Survival curves were estimated by the Kaplan-Meier method and compared by log-rank test. Multivariate analysis was performed with Cox proportional and logistic regression.

RESULTS

Thirty-one patients (37 percent) had involvement of the pelvic wall, whereas 53 patients (63 percent) had visceral involvement only. All 29 patients with distant metastasis died of their disease. Forty-seven of the 55 patients without distant metastasis underwent tumor resection. Age and pelvic wall involvement were the only two factors independently associated with the probability of resection in logistic regression analysis (P = 0.0067 and P = 0.037, respectively). The only factor that affected median survival in patients without distant metastasis was tumor resection (49.1 months for resection vs. 6.1 months for no resection, P = 0.017). Patients with visceral involvement had a longer median survival (49.2 months) than those with pelvic wall involvement (13.2 months), but the difference did not reach statistical significance (P = 0.058).

CONCLUSION

Rectal cancers with pelvic and visceral involvement have different rates of resectability and median survival. These differences should be reflected in the TNM classification system.

Role of local excision in the treatment of rectal cancer

Local excision (LE) of properly selected rectal cancers can provide long-term survival, with minimal morbidity, negligible mortality, and excellent functional results. The role of LE has evolved over the past century. Initially, to avoid the excessive mortality of abdominal surgery, aggressive LE was performed to control the symptoms of rectal cancer. As abdominal surgery became safer, LE was restricted for use in palliation or high-risk patients. Better preoperative tumor staging resulted in an expanded role for LE, including curative-intent treatment of selected T(1-2) rectal cancers. Techniques for LE include snare polypectomy, transanal excision, transanal endoscopic microsurgery, and posterior approaches. The high local recurrence rate and compromised survival reported in modern series, despite efforts to properly select patients with cancers suitable for LE, have convinced the authors to restrict the use of curative-intent LE in good-risk patients only to the most favorable rectal cancers. Close follow-up after LE is critical, because radical surgical salvage is usually possible if recurrence is identified promptly. Whether adjuvant chemoradiation can expand the role of curative intent LE remains controversial.

Local excision of rectal cancer without adjuvant therapy: a word of caution

OBJECTIVE

To evaluate the results of local excision alone for the treatment of rectal cancer, applying strict selection criteria.

BACKGROUND DATA

Several retrospective studies have demonstrated that tumor control in properly selected patients with rectal cancer treated locally is comparable to that observed after radical surgery. Although there is a consensus regarding the need for patient selection for local excision, the specific criteria vary among centers.

METHODS

The authors reviewed 82 patients with T1 (n = 55) and T2 (n = 27) rectal cancer treated with transanal excision only during a 10-year period. At pathologic examination, all tumors were localized to the rectal wall, had negative excision margins, were well or moderately differentiated, and had no blood or lymphatic vessel invasion, nor a mucinous component. End points were local and distant tumor recurrence and patient survival.

RESULTS

Ten of the 55 patients with T1 tumors (18%) and 10 of the 27 patients with T2 tumors (37%) had recurrence at 54 months of follow-up. Average time to recurrence was 18 months in both groups. Seventeen of the 20 patients with local recurrence underwent salvage surgery. The survival rate was 98% for patients with T1 tumors and 89% for patients with T2 tumors. Preoperative staging by endorectal ultrasound did not influence local recurrence or tumor-specific survival.

CONCLUSION

Local excision of early rectal cancer, even in the ideal candidate, is followed by a much higher recurrence rate than previously reported. Although most patients in whom local recurrence develops can be salvaged by radical resection, the long-term outcome remains unknown.

Risks of the minimal access approach for laparoscopic surgery: multivariate analysis of morbidity related to umbilical trocar insertion

The objective of this study was to determine the morbidity associated with trocar and needle insertion for laparoscopic surgery and to identify risk factors for complications. Data from a prospectively collected database of all laparoscopic operations performed at a major teaching hospital over a 4-year period were analyzed. In 203 patients closed laparoscopy (Veress needle plus blind trocar insertion) was used to establish the pneumoperitoneum. Open laparoscopy with a Hasson's trocar was performed in 200 patients. A total of 1206 operative trocars were inserted (mean +/- SD 2.99 +/- 0.4). Sixty-nine percutaneous punctures for cholangiography or liver biopsy were carried out. Of the 403 patients undergoing laparoscopic surgery, 20 (3%) had developed complications specifically related to the access to the abdominal cavity after a minimum follow-up of 3 months, abdominal wall hematoma being the most frequent (n = 8, 2.0%), followed by umbilical hernias (n = 6, 1.5%) and umbilical wound infection (n = 5; 1.2%). The rate of penetrating injuries was 0.2% (n = 1). Of 20 complications, 15 (75%) were related to the umbilical insertion site. Female sex and closed laparoscopy were associated with umbilical morbidity by univariate analysis. In a multivariate analysis, closed laparoscopy was the only factor associated with these complications (odds ratio = 6.0; p = 0.04). Age, gender, obesity, diabetes mellitus, previous abdominal surgery, and the specific procedure had no influence. In conclusion, gaining access to the peritoneal cavity for laparoscopic surgery may cause severe complications, most of which are related to the umbilical trocar. Although closed laparoscopy can be safely used, open laparoscopy is associated with a lower morbidity rate; therefore its utilization is recommended.

Anal fistula surgery. Factors associated with recurrence and incontinence

PURPOSE

This study was undertaken to assess results of surgery for fistula-in-ano and identify risk factors for fistula recurrence and impaired continence.

METHODS

We reviewed the records of 624 patients who underwent surgery for fistula-in-ano between 1988 and 1992. Follow-up was by mailed questionnaire, with 375 patients (60 percent) responding. Mean follow-up was 29 months. Fistulas were intersphincteric in 180 patients, transsphincteric in 108, suprasphincteric in 6, extrasphincteric in 6, and unclassified in 75. Procedures included fistulotomy and marsupialization (n = 300), seton placement (n = 63), endorectal advancement flap (n = 3), and other (n = 9). Factors associated with recurrence and incontinence were analyzed by univariate and multivariate regression analysis.

RESULTS

The fistula recurred in 31 patients (8 percent), and 45 percent complained of some degree of postoperative incontinence. Factors associated with recurrence included complex type of fistula, horseshoe extension, lack of identification or lateral location of the internal fistulous opening, previous fistula surgery, and the surgeon performing the procedure. Incontinence was associated with female sex, high anal fistula, type of surgery, and previous fistula surgery.

CONCLUSIONS

Surgical treatment of fistula-in-ano is associated with a significant risk of recurrence and a high risk of impaired continence. Degree of risk varies with identifiable factors.

Open vs. closed sphincterotomy for chronic anal fissure: long-term results

PURPOSE

This study was undertaken to compare the healing rate and long-term effects on continence of open and closed lateral internal sphincterotomy.

METHODS

Charts of 864 patients with chronic anal fissure who underwent internal sphincterotomy as a single procedure over five years by a group of 12 colorectal surgeons were reviewed. Open internal sphincterotomy (OIS) was performed in 521 patients, whereas 343 had closed internal sphincterotomy (CIS). There was no difference in sex or age between the groups. A questionnaire inquiring about clinical outcome, changes in continence, and degree of satisfaction with the procedure was mailed to all patients. A total of 549 (63.5 percent) patients, 324 (62.2 percent) with OIS and 225 (65.6 percent) with CIS, returned their questionnaires. Average follow-up was three (range, 1-6) years.

RESULTS

Differences in persistence of symptoms (3.4 OIS vs. 5.3 percent CIS), recurrence of the fissure (10.9 vs. 11.7 percent CIS), and need for reoperation (3.4 percent OIS vs. 4 percent CIS) were statistically not significant. However, statistically significant differences were seen in the percentage of patients with permanent postoperative difficulty controlling gas (30.3 vs. 23.6 percent; P 0.062), soiling underclothing (26.7 vs. 16.1 percent; P < 0.001), and accidental bowel movements (11.8 vs. 3.1 percent; P < 0.001) between those who underwent OIS and those who had CIS. Although 90 percent of patients reported general overall satisfaction, more patients undergoing CIS (64.4 percent) than OIS (49.7 percent) were very satisfied with the results of the procedure.

CONCLUSIONS

Lateral internal sphincterotomy is highly effective in treatment of chronic anal fissure but is associated with significant permanent alterations in continence. CIS is preferable to OIS because it effects a similar rate of cure with less impairment of control.

Isoperistaltic jejunal interposition for intractable postgastrectomy alkaline reflux gastritis

BACKGROUND

The Roux-en-Y gastrojejunostomy is a popular method in the operative treatment of alkaline reflux gastritis and other postgastrectomy sequelae, but is associated with a high incidence of the so-called "Roux stasis syndrome." The Henley jejunal interposition has been used occasionally, albeit not widely, as an alternative to the Roux-en-Y reconstruction.

STUDY DESIGN

Six patients underwent Henley gastrojejunoduodenostomy to treat severe (Visick grade IV) symptoms following Billroth I and II procedures for peptic ulcer disease. All interposed jejunal segments were 40 cm in length and isoperistaltic in orientation. All patients had follow-up examination and telephone interview (mean 4.3 years, range 2.2 to 7.8 years).

RESULTS

All patients noted dramatic improvement after remedial surgery in the first year of follow-up. After the first postoperative year, all patients remained virtually symptom-free (Visick grade I and II) with no complaints of gastrojejunal stasis or bile acid reflux.

CONCLUSIONS

This experience suggests that the Henley jejunal interposition is our effective method of treating reflux gastritis and is not associated with the poor emptying frequently associated with the Roux-en-Y reconstruction.

The I domain is a major recognition site on the leukocyte integrin Mac-1 (CD11b/CD18) for four distinct adhesion ligands

Despite the identification and characterization of several distinct ligands for the leukocyte integrin (CD11/CD18) family of adhesion receptors, little is known about the structural regions on these molecules that mediate ligand recognition. In this report, we use alpha subunit chimeras of Mac-1 (CD11b/CD18) and p150,95 (CD11c/CD18), and an extended panel of newly generated and previously characterized mAbs specific to the alpha chain of Mac-1 to map the binding sites for four distinct ligands for Mac-1: iC3b, fibrinogen, ICAM-1, and the as-yet uncharacterized counter-receptor responsible for neutrophil homotypic adhesion. Epitopes of mAbs that blocked ligand binding were mapped with the chimeras and used to localize the ligand recognition sites because the data obtained from functional assays with the Mac-1/p150,95 chimeras were not easily interpreted. Results show that the I domain on the alpha chain of Mac-1 is an important recognition site for all four ligands, and that the NH2-terminal and perhaps divalent cation binding regions but not the COOH-terminal segment may contribute. The recognition sites in the I domain appear overlapping but not identical as individual Mac-1-ligand interactions are distinguished by the discrete patterns of inhibitory mAbs. Additionally, we find that the alpha subunit NH2-terminal region and divalent cation binding region, despite being separated by over 200 amino acids of the I domain, appear structurally apposed because three mAbs require the presence of both of these regions for antigenic reactivity, and chimeras that contain the NH2 terminus of p150,95 require the divalent cation binding region of p150,95 to associate firmly with the beta subunit.

ICAM-1 (CD54): a counter-receptor for Mac-1 (CD11b/CD18)

While the leukocyte integrin lymphocyte function-associated antigen (LFA)-1 has been demonstrated to bind intercellular adhesion molecule (ICAM)-1, results with the related Mac-1 molecule have been controversial. We have used multiple cell binding assays, purified Mac-1 and ICAM-1, and cell lines transfected with Mac-1 and ICAM-1 cDNAs to examine the interaction of ICAM-1 with Mac-1. Stimulated human umbilical vein endothelial cells (HUVECs), which express a high surface density of ICAM-1, bind to immunoaffinity-purified Mac-1 adsorbed to artificial substrates in a manner that is inhibited by mAbs to Mac-1 and ICAM-1. Transfected murine L cells or monkey COS cells expressing human ICAM-1 bind to purified Mac-1 in a specific and dose-dependent manner; the attachment to Mac-1 is more temperature sensitive, lower in avidity, and blocked by a different series of ICAM-1 mAbs when compared to LFA-1. In a reciprocal assay, COS cells cotransfected with the alpha and beta chain cDNAs of Mac-1 or LFA-1 attach to immunoaffinity-purified ICAM-1 substrates; this adhesion is blocked by mAbs to ICAM-1 and Mac-1 or LFA-1. Two color fluorescence cell conjugate experiments show that neutrophils stimulated with fMLP bind to HUVEC stimulated with lipopolysaccharide for 24 h in an ICAM-1-, Mac-1-, and LFA-1-dependent fashion. Because cellular and purified Mac-1 interact with cellular and purified ICAM-1, we conclude that ICAM-1 is a counter receptor for Mac-1 and that this receptor pair is responsible, in part, for the adhesion between stimulated neutrophils and stimulated endothelial cells.

Genomic structure of an integrin alpha subunit, the leukocyte p150,95 molecule

The genomic structure of integrins is important to our understanding of the evolution of this complex family. The alpha subunit of the leukocyte integrin p150,95 (CD11c) is a transmembrane polypeptide of 1144 residues whose long extracellular region contains three putative divalent cation binding repeats and a 200- amino acid inserted or "I" domain. The p150,95 alpha subunit gene extends over 25 kilobases and is comprised of at least 31 exons grouped in five clusters. The I domain, which is only present in some integrins and is homologous to domains in von Willebrand factor, cartilage matrix protein, complement factor B and the alpha 1 and alpha 2 chains of collagen type VI, is distributed in four exons. Each one of the three divalent cation binding repeats is encoded by a separate exon. Surprisingly, a sequence homologous to the first two putative divalent cation binding repeats is present in an inverted orientation in the intron following the last exon of the I domain. Both the signal peptide and the transmembrane domain are split in two exons. Putative proteolytic cleavage sequences in other integrin alpha subunits align as inserts within the p150,95 alpha subunit gene falling at exon boundaries. The organization of the p150,95 alpha subunit gene provides further insights into the structure and evolution of the integrins.

Coagulation increases neutrophil CR1 and CR3 expression: primary role for platelet-derived growth factor

Neutrophil receptors for C3b(CR1) and C3bi(CR3) mediate a number of functions important for infection control and tissue repair, such as adherence, aggregation, orientation in chemotactic gradients, and phagocytosis of opsonized particles. We studied the effect of the coagulation of whole blood on the induction of neutrophil complement receptor (CR) expression in vitro. Neutrophils incubated in serum for 1 hour at 37 degrees C increased the expression of CR1 3.43-fold and CR3 3.06-fold compared with incubation in buffer (p less than 0.001). In contrast, incubation in plasma did not induce such an increase. The serum factor responsible for this CR-inducing effect appeared to be a platelet constituent, because (1) serum derived from platelet-rich plasma, but not platelet-poor plasma, contained the CR-inducing factor; (2) pretreatment with aspirin inhibited the adenosine diphosphate-induced expression of this factor in platelet-rich plasma; (3) the CR-inducing factor was also contained in supernatants derived from frozen/thawed platelets; (4) pure platelet-derived growth factor (PDGF) induced CR expression to the same extent as did whole serum; and (5) the CR-inducing activity of serum and platelet supernatants was inhibited by incubation with antibody against PDGF but not by antibody against C5. Thus, a platelet component that is probably PDGF appears to be the major CR-inducing factor generated during in vitro coagulation and may play a vital role in mediating the neutrophil response to tissue injury and inflammation.

Neutrophil CR3 induction by platelet supernatants is due to platelet-derived growth factor

Recently, serum was shown to contain a factor that increased expression of the complement receptor CR3 on neutrophil membranes. This factor was localized to platelet granules and was released during coagulation. This study was undertaken to identify this factor in platelet granules. Platelet supernatants containing granule contents were incubated with neutrophils, and CR3 expression was determined by flow cytometry. Incubation with platelet supernatants induced more than a twofold increase in the amount of CR3 expressed on the neutrophil membrane (p = 0.05). Anti-platelet-derived growth factor (anti-PDGF) Fab, when preincubated with the platelet supernatants, completely inhibited this CR3-inducing activity. Pure PDGF induced a dose-response increase in CR3, whereas platelet factor 4 had no effect. PDGF was active in concentrations well within the physiologic range. These data indicate that PDGF is responsible for the CR3-inducing activity of platelet supernatants. PDGF may well be an important regulator of neutrophil adherence and phagocytic function in areas of tissue injury.

Coagulation augments neutrophil C3b receptors via formation of a protein(s) unrelated to fibrinolysis or C5 activation

The present study investigated the effect of coagulation on neutrophil complement receptors (CRs) 1 and 3, which are specific for the opsonins C3b and C3bi. Incubation of neutrophils in autologous serum, but not in plasma, increased the mean (+/- SD) expression of CR1 (x3.43 +/- 0.93) and CR3 (x3.07 +/- 0.86), in comparison with incubation in buffer. Serum also increased neutrophil superoxide production in response to opsonized zymosan from 0.48 +/- 0.21 to 1.05 +/- 0.25 nmol/10(6) cells/min. Similarly, calcium conversion of platelet-rich plasma (but not platelet-poor plasma) to serum also increased both CR1 and CR3 expression. This finding, as well as the fact that freeze-thawed platelet-rich plasma (but not platelet-poor plasma) increased CR expression, indicated that platelet constituents were the origin of this CR-inducing activity. Other nonplatelet factors formed during coagulation, such as C5a, fibrinogen degradation products, kallikrein, and factor XIIa, were shown not to be responsible for this CR-inducing activity.