Summary 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 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.

https://www.thelancet.com/pdfs/journals/lanonc/PIIS1470-2045(10)70172-8.pdf

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

Cancer stem cells (CSCs) have recently been identified in leukaemia and solid tumours; however, the role of CSCs in metastasis remains poorly understood. This dearth of knowledge about CSCs and metastasis is due largely to technical challenges associated with the use of primary human cancer cells in pre-clinical models of metastasis. Therefore, the objective of this study was to develop suitable pre-clinical model systems for studying stem-like cells in breast cancer metastasis, and to test the hypothesis that stem-like cells play a key role in metastatic behaviour. We assessed four different human breast cancer cell lines (MDA-MB-435, MDA-MB-231, MDA-MB-468, MCF-7) for expression of prospective CSC markers CD44/CD24 and CD133, and for functional activity of aldehyde dehydrogenase (ALDH), an enzyme involved in stem cell self-protection. We then used fluorescence-activated cell sorting and functional assays to characterize differences in malignant/metastatic behaviour in vitro (proliferation, colony-forming ability, adhesion, migration, invasion) and in vivo (tumorigenicity and metastasis). Sub-populations of cells demonstrating stem-cell-like characteristics (high expression of CSC markers and/or high ALDH) were identified in all cell lines except MCF-7. When isolated and compared to ALDHlowCD44low/– cells, ALDHhiCD44+CD24− (MDA-MB-231) and ALDHhiCD44+CD133+ (MDA-MB-468) cells demonstrated increased growth (P < 0.05), colony formation (P < 0.05), adhesion (P < 0.001), migration (P < 0.001) and invasion (P < 0.001). Furthermore, following tail vein or mammary fat pad injection of NOD/SCID/IL2γ receptor null mice, ALDHhiCD44+CD24− and ALDHhiCD44+CD133+ cells showed enhanced tumorigenicity and metastasis relative to ALDHlowCD44low/– cells (P < 0.05). These novel results suggest that stem-like ALDHhiCD44+CD24− and ALDHhiCD44+CD133+ cells may be important mediators of breast cancer metastasis.

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High aldehyde dehydrogenase and expression of cancer stem cell markers selects for breast cancer cells with enhanced malignant and metastatic ability.

Estrogen receptor (ER)-negative breast cancer specimens are predominantly of high grade, have frequent p53 mutations, and are broadly divided into HER2-positive and basal subtypes. Although ER-negative disease has overall worse prognosis than does ER-positive breast cancer, not all ER-negative breast cancer patients have poor clinical outcome. Reliable identification of ER-negative tumors that have a good prognosis is not yet possible. We apply a recently proposed feature selection method in an integrative analysis of three major microarray expression datasets to identify molecular subclasses and prognostic markers in ER-negative breast cancer. We find a subclass of basal tumors, characterized by over-expression of immune response genes, which has a better prognosis than the rest of ER-negative breast cancers. Moreover, we show that, in contrast to ER-positive tumours, the majority of prognostic markers in ER-negative breast cancer are over-expressed in the good prognosis group and are associated with activation of complement and immune response pathways. Specifically, we identify an immune response related seven-gene module and show that downregulation of this module confers greater risk for distant metastasis (hazard ratio 2.02, 95% confidence interval 1.2-3.4; P = 0.009), independent of lymph node status and lymphocytic infiltration. Furthermore, we validate the immune response module using two additional independent datasets. We show that ER-negative basal breast cancer is a heterogeneous disease with at least four main subtypes. Furthermore, we show that the heterogeneity in clinical outcome of ER-negative breast cancer is related to the variability in expression levels of complement and immune response pathway genes, independent of lymphocytic infiltration.

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An immune response gene expression module identifies a good prognosis subtype in estrogen receptor negative breast cancer

Cancer cell invasion into healthy tissues develops preferentially along pre-existing tracks of least resistance, followed by secondary tissue remodelling and destruction. The tissue scaffolds supporting or preventing guidance of invasion vary in structure and molecular composition between organs. In the brain, the guidance is provided by myelinated axons, astrocyte processes, and blood vessels which are used as invasion routes by glioma cells. In the human breast, containing interstitial collagen-rich connective tissue, disseminating breast cancer cells preferentially invade along bundled collagen fibrils and the surface of adipocytes. In both invasion types, physical guidance prompted by interfaces and space is complemented by molecular guidance. Generic mechanisms shared by most, if not all, tissues include (i) guidance by integrins towards fibrillar interstitial collagen and/or laminins and type IV collagen in basement membranes decorating vessels and adipocytes, and, likely, CD44 engaging with hyaluronan; (ii) haptotactic guidance by chemokines and growth factors; and likely (iii) physical pushing mechanisms. Tissue-specific, resticted guidance cues include ECM proteins with restricted expression (tenascins, lecticans), cell-cell interfaces, and newly secreted matrix molecules decorating ECM fibres (laminin-332, thrombospondin-1, osteopontin, periostin). We here review physical and molecular guidance mechanisms in interstitial tissue and brain parenchyma and explore shared principles and organ-specific differences, and their implications for experimental model design and therapeutic targeting of tumour cell invasion.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/path.3031

Interstitial guidance of cancer invasion

PURPOSE: Preoperative chemoradiation therapy is used widely in the treatment of rectal cancer. The predictive value of response to neoadjuvant remains uncertain. We retrospectively evaluated the impact of response to preoperative and, specifically, of T-level downstaging, nodal downstaging, and complete pathologic response after chemoradiation therapy on oncologic outcome of patients with locally advanced rectal cancer. METHODS: There were 88 patients with ultrasound Stage T3/T4 midrectal (n = 37) and low rectal (n = 51) cancers (63 males; mean age 62.6 years). All patients were treated by preoperative 5-fluorouracil-based chemotherapy and pelvic radiation followed by surgical resection in six weeks or longer (56 sphincter-preserving resections). RESULTS: T-level downstaging after neoadjuvant treatment was demonstrated in 36 (41 percent) of 88 patients, and complete pathologic response was observed in 16 (18 percent) of the 88. Of the 42 patients with ultrasound-positive nodes, 27 had no evidence of nodal involvement on pathologic evaluation (64 percent). The overall response rate (T-level downstaging or nodal downstaging) was 51 percent. At a median follow-up of 33 months, 86.4 percent of patients were alive. The overall recurrence rate was 10.2 percent (three patients had local and six had metastatic recurrences). Patients with T-level downstaging and complete pathologic response were characterized by significantly better disease-free survival (P = 0.03, P = 0.04) and better overall survival (P = 0.07, P = 0.08), according to Wilcoxon’s test comparing Kaplan-Meier survival curves. None of the patients with complete pathologic response developed recurrence or died during the follow-up period. CONCLUSION: T-level downstaging and complete pathologic response after preoperative chemoradiation therapy followed by definitive surgical resection for advanced rectal cancer resulted in decreased recurrence and improved disease-free survival. Advanced rectal cancers that undergo T-level downstaging and complete pathologic response after chemoradiation therapy may represent subgroups that are characterized by better biologic behavior.

T-Level Downstaging and Complete Pathologic Response After Preoperative Chemoradiation for Advanced Rectal Cancer Result in Decreased Recurrence and Improved Disease-Free Survival

Although a primary route of breast cancer metastasis is believed to be via lymphatics, the molecular factors involved are poorly understood. We hypothesized that one such factor may be the integrin-binding protein osteopontin (OPN), and we investigated this clinically and experimentally. In breast cancer patients undergoing sentinel lymph node biopsy, OPN levels were significantly higher in lymph node metastases than in the primary tumor (P < 0.001). To test the functional contribution of OPN to lymphatic metastasis and to determine whether the RGD (Arg-Gly-Asp) integrin-binding sequence of OPN is important for this process, we transfected wild-type OPN or mutant OPN (lacking the RGD sequence) into MDA-MB-468 human breast cancer cells. In vitro, cells overexpressing OPN demonstrated increased anchorage-independent growth in soft agar (P = 0.001) and increased RGD-dependent adhesion (P = 0.045). Following mammary fat pad injection of nude mice, cells overexpressing OPN showed increased lymphovascular invasion, lymph node metastases, and lung micrometastases at earlier time points (P = 0.024). Loss of the RGD region partially abrogated this effect in the lymphatics (P = 0.038). These novel findings indicate that OPN is a key molecular player involved in lymphatic metastasis of breast cancer, potentially by affecting RGD-mediated adhesive interactions and by enhancing the establishment/persistence of tumor cells in the lymphatics.

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Role of the integrin-binding protein osteopontin in lymphatic metastasis of breast cancer.

Background and Purpose: To determine the percentage of complete responders and the resectability rate for patients with locally advanced carcinoma of the rectum treated by 5-fluorouracil (5-FU) infusional chemotherapy and pelvic radiation. Materials and Methods: Between October 1992 and June 1996, 29 patients with a diagnosis of locally advanced unresectable rectal cancer received preoperative 5 FU by continuous intravenous infusion at a dose of 225 mg/m 2 /day concurrent with pelvic radiation (median 54 Gy/28 fractions). All patients were clinical stage T4 on the bases of organ invasion or tumor fixation. Median time for surgical resection was 6 weeks. Results: Median follow-up for the group was 28 months (range 5–57 months). Six patients were felt to be persistently unresectable or developed distant metastases and did not undergo surgical resection. Of the 29 patients, 23 proceeded to surgery, 18 were resectable for cure, 13 by abdominoperineal resection, 3 by anterior resection and 2 by local excision. Of the 29 patients, 4 (13%) had a complete response, and 90% were clinically downstaged. Of the 18 resected patients, 1 has died of his disease, 17 are alive, and 15 disease-free. The regimen was well tolerated; there was only one treatment-related complication, a wound dehiscence. Conclusion: The combination of 5 FU infusion and pelvic radiation in the management of locally advanced rectal cancer is well tolerated and provides a baseline for comparison purposes with future combinations of newer systemic agents and radiation.

Preoperative radiation with concurrent 5-fluorouracil continuous infusion for locally advanced unresectable rectal cancer

After breast-conserving surgery, positive margins occur when breast cancer cells are found on the resection margin, leading to a higher chance of recurrence and the need for repeat surgery. The NaviKnife is an electromagnetic tracking-based surgical navigation system that helps to provide visual and spatial feedback to the surgeon. In this study, we conduct a gross evaluation of this navigation system with respect to resection margins. The trajectory of the surgical cautery relative to ultrasound-visible tumor will be visualized, and its distance and location from the tumor will be compared with pathology reports. Six breast-conserving surgery cases that resulted in positive margins were performed using the NaviKnife system. Trackers were placed on the surgical tools and their positions in three-dimensional space were recorded throughout the procedure. The closest distance between the cautery and the tumor throughout the procedure was measured. The trajectory of the cautery when it came closest to the tumor model was plotted in 3D Slicer and compared with pathology reports. In two of the six cases, the side at which the cautery came the closest to the tumor model coincided with the side at which positive margins were found from pathology reports. Our method shows that positive margins occur mainly in areas that are not visible from ultrasound imaging. Our system will need to be used in combination with intraoperative tissue characterization methods to effectively predict the occurrence and location of positive margins.

C. Jay Engel

Papers

Role of the integrin-binding protein osteopontin in lymphatic metastasis of breast cancer.

Preoperative radiation with concurrent 5-fluorouracil continuous infusion for locally advanced unresectable rectal cancer

Cautery trajectory analysis for evaluation of resection margins in breast-conserving surgery

Real-time automatic tumor segmentation for ultrasound-guided breast-conserving surgery navigation