DNA ploidy pattern in rectal carcinoid tumors

Molecular profiling of neuroendocrine tumours to predict response and toxicity to peptide receptor radionuclide therapy

Peptide receptor radionuclide therapy (PRRT) is a type of radiotherapy that targets peptide receptors and is typically used for neuroendocrine tumours (NETs). Some of the key challenges in its use are the prediction of efficacy and toxicity, patient selection, and response optimisation. In this Review, we assess current knowledge on the molecular profile of NETs and the strategies and tools used to predict, monitor, and assess the toxicity of PRRT. The few mutations in tumour genes that can be evaluated (eg, ATM and DAXX) are limited to pancreatic NETs and are most likely not informative. Assays that are transcriptomic or based on genes are effective in the prediction of radiotherapy response in other cancers. A blood-based assay for eight genes (the PRRT prediction quotient [PPQ]) has an overall accuracy of 95% for predicting responses to PRRT in NETs. No molecular markers exist that can predict the toxicity of PRRT. Candidate molecular targets include seven single nucleotide polymorphisms (SNPs) that are susceptible to radiation. Transcriptomic evaluations of blood and a combination of gene expression and specific SNPs, assessed by machine learning with algorithms that are tumour-specific, might yield molecular tools to enhance the efficacy and safety of PRRT.

Management of sub-5 mm rectal carcinoids with lymph node metastases

Minute (<5 mm) and small (5–10 mm) rectal carcinoids discovered during colonoscopy are generally considered to be non-aggressive, and the management and surveillance of patients with this entity are usually limited. We present the case of a 61-year-old Chinese female with multiple sub-5 mm carcinoid tumours in the rectum without any computed tomography (CT) evidence of lymph node or distant metastases. She underwent an ultra-low anterior resection for a sessile rectal polyp with the histological appearance of a moderately differentiated adenocarcinoma. Seven foci of minute carcinoids in the rectum and perirectal lymph node metastastic spread from the carcinoid tumours were also discovered on histopathology. There were no lymph node metastases originating from adenocarcinoma. This case report and review of the literature suggests that minute rectal carcinoids are at risk of metastasizing and that these patients should be investigated for lymph node and distant metastatic spread with CT and somatostatin receptor scintigraphy or its equivalent, as this would influence prognosis and surgical management of these patients. Findings relating to lymphovascular invasion, perineural invasion, high Ki-67, mitotic rate, depth of tumour invasion, central ulceration, multifocal tumours and size are useful in predicting metastases and may be used in scoring tools. Size alone is not a good predictor of metastastic spread.

Viability of endoscopic and excisional treatment of early rectal carcinoids

With the advent of endoscopy, the incidence of rectal carcinoid tumors has not only risen, but the majority are localized at presentation. This has led to excisional and/or ablative therapy in lieu of radical resections. A single institute's experience with rectal carcinoids was reviewed to determine the impact this approach has had on outcomes, and evaluate any selection criteria for optimizing patient survival. A single institute's tumor registry was retrospectively queried, identifying 14 patients with rectal carcinoid tumors over a 28-year period. The mean age at diagnosis was 52.1 +/- 14.4 years. Six of the 14 patients were female. Presenting symptoms included a change in bowel habits in six (38%), rectal bleeding in six (38%), and abdominal pain or distention in five (31%) patients. No patient had symptoms consistent with carcinoid syndrome. The rectal carcinoids were a mean 9.2 +/- 3.4 cm from the anal verge and a mean 9 +/- 6 mm in size. Endoscopic and/or transanal excision/fulguration techniques treated 11 (79%) patients, whereas two (14%) patients underwent a low anterior resection (LAR). Surveillance entailed periodic endoscopy for a median 65 months (range 8-281). No patient developed recurrent carcinoid disease for a 20-year overall survival of 70%.

Current status of gastrointestinal carcinoids

Gastrointestinal (GI) carcinoids are ill-understood, enigmatic malignancies, which, although slow growing compared with adenocarcinomas, can behave aggressively. Carcinoids are classified based on organ site and cell of origin and occur most frequently in the GI (67%) where they are most common in small intestine (25%), appendix (12%), and rectum (14%). Local manifestations--mass, bleeding, obstruction, or perforation--reflect invasion or tumor-induced fibrosis and often result in incidental detection at emergency surgery. Symptoms are protean (flushing, sweating, diarrhea, bronchospasm), usually misdiagnosed, and reflect secretion of diverse amines and peptides. Biochemical diagnosis is established by elevation of plasma chromogranin A (CgA), serotonin, or urinary 5-hydroxyindoleacetic acid (5-HIAA), while topographic localization is by Octreoscan, computerized axial tomography (CAT) scan, or endoscopy/ultrasound. Histological identification is confirmed by CgA and synaptophysin immunohistochemistry. Primary therapy is surgical excision to avert local manifestations and decrease hormone secretion. Hepatic metastases may be amenable to cytoreduction, radiofrequency ablation, embolization alone, or with cytotoxics. Hepatic transplantation may rarely be beneficial. Chemotherapy and radiotherapy have minimal efficacy and substantially decrease quality of life. Intravenously administered receptor-targeted radiolabeled somatostatin analogs are of use in disseminated disease. Local endoscopic excision for gastric (type I and II) and rectal carcinoids may be adequate. Somatostatin analogues provide the most effective symptomatic therapy, although interferon has some utility. Overall 5-year survival for carcinoids of the appendix is 98%, gastric (types I/II) is 81%, rectum is 87%, small intestinal is 60%, colonic carcinoids is 62%, and gastric type III/IV is 33%.

Review article: current status of gastrointestinal carcinoids

Carcinoid tumours are enigmatic, slow growing malignancies which occur most frequently (74%) in the gastrointestinal tract. In recent years, it has become apparent that the term 'carcinoid' represents a wide spectrum of different neoplasms originating from a variety of different neuroendocrine cell types. Carcinoid lesions are usually identified histologically by their affinity for silver salts, by general neuroendocrine markers, or more specifically by immunocytochemistry using antibodies against their specific cellular products. Within the gut, the most frequent sites are the small bowel (29%), the appendix (19%) and rectum (13%). Clinical manifestations are often vague or absent. Nevertheless, in approximately 10% of patients the tumours secrete bioactive mediators which may engender various elements of characteristic carcinoid syndrome. In many instances the neoplasms are detected incidentally at the time of surgery for other gastrointestinal disorders. The tendency for metastatic spread correlates with tumour size, and is substantially higher in lesions larger than 2.0 cm. An association with noncarcinoid neoplasms is ascribed in 8-17% of lesions. Treatment consists of radical surgical excision of the tumour, although gastric (type I and II) and rectal carcinoids may be managed with local excision. Overall 5-year survival is excellent for carcinoids of the appendix (86%) and rectum (72%), whereas small intestinal (55%), gastric (49%) and colonic carcinoids (42%) exhibit a far worse prognosis.

Carcinoid tumor of the rectum. DNA ploidy is not a prognostic factor

PURPOSE

This study was designed to evaluate the clinical characteristics, surgical treatment, and outcome of carcinoid tumors of the rectum and to assess flow cytometry deoxyribonucleic acid (DNA) analysis as a potential prognostic factor for management of these tumors.

METHODS

Medical records, tumor registry database, and pathology slides were retrospectively reviewed. Flow cytometry DNA analysis was performed on archived specimens.

RESULTS

One hundred nine patients with rectal carcinoid tumors underwent surgery between 1962 and 1987. Follow-up was available in 86 patients for a mean period of 12 years. Of 100 patients with tumors less than 2 cm, only one with a 1.5 cm ulcerated tumor developed liver metastases. Of nine patients with a tumor more than or equal to 2 cm, three with known liver metastases underwent rectal biopsy only, and three had rectal biopsy and laparotomy with biopsy of liver metastases. Three patients underwent radical resection. Following abdominoperineal resection, one patient died with local recurrence after 5 years, and one developed hepatic recurrence after 5.5 years and died at 9 years. One patient with coloanal anastomosis developed local and hepatic metastases seven years after surgery and died at ten years. No patients developed carcinoid syndrome. DNA ploidy did not correlate with metastases at presentation or recurrence of carcinoid tumor.

CONCLUSION

Radical resection of rectal carcinoids with ulceration or size greater than or equal to 2 cm is associated with a poor prognosis; however, survival may be long term, even in the presence of metastatic disease. DNA ploidy does not appear to be a useful prognostic factor for rectal carcinoid tumors.

Cytophotometric DNA-analysis of bone-tumors. A new method for preparing formalin-fixed tissue and the regarding of DNA-malignancy grade and its prognostic value

78 benign and malign, formalin-fixed bone or bone-associated tumors of different origin were prepared for image-cytophotometric measuring with a new method of preparing. The DNA-content of the tumors and the so resulting malignancy-grade were determined and compared with the corresponding measurements of unprepared fresh tumors respectively paraffin-embedded tissue sections. Regarding the comparison of the fresh material with the formalin-fixed material, no significant difference (p < or = 0.01) of the data could be found. There was also no significant difference (p < or = 0.01) concerning the comparison of the data obtained from the formalin-fixed material and the data from the tissue sections. The criterium aneuploidy showed a sensitivity of 86% and a specificity of 100% in regards to identifying a malignant tumor, irrespective of the preparation method. A strong correlation could be found (p < 0.001) between the DNA-malignancy grade and the survival rate of the patients.

The value of cytometric DNA analysis as a prognostic tool in neuroendocrine neoplastic diseases

In several traditionally non-endocrine, common, human, neoplastic diseases, it has become well established during the last few years, that cytometric analyses of the DNA distribution pattern of the nuclei of tumour cells can be an excellent supplement to the conventional prognostic tools, (such as clinical staging and histopathologic malignancy assessments). When analogous studies of the value of DNA analysis by means of flow cytometry and/or image cytometry are made in neuroendocrine (NE) neoplastic diseases, the ensuing results often become rather disappointing. Thus, clear-cut aneuploid DNA histograms can be found in the neoplastic cell nuclei of clinically and histopathologically completely benign NE adenomas (and even hyperplastic nodules). In contrast, highly aggressive NE carcinomas not seldom reveal themselves to be composed of tumour cells with nuclei, displaying an euploid, i.e. normal, DNA pattern. Statements of this kind have been based on the results of comprehensive investigations in several laboratories, analysing such NE tumours as insulomas/insular carcinomas, bronchial/gastrointestinal carcinoids, phaeochromocytomas, paragangliomas, neuroblastomas, adenomas of the anterior pituitary gland, parathyroid adenomas, medullary carcinoma of the thyroid and Merkel-cell tumours of the skin. Thus, the prognostic value of the cytometric DNA ploidy pattern of the nuclei of neoplastic parenchymal cells is definitely lower in NE tumours than in most of the traditionally non-endocrine carcinomas and sarcomas. Data from published and unpublished series of these kinds of NE tumours, and those of prostatic and breast carcinomas with NE differentiation, are given. By means of a new, consecutive double staining technique, it was shown that in idiopathic nesidioblastosis, the hyperinsulinism is caused by beta cells with a nuclear DNA ploidy pattern of euploid type. By the same technique, it can be shown that in the pathogenesis of the hypergastrinaemia-induced ECL-cell carcinoids of the stomach, a switch from an euploid to an aneuploid nuclear DNA distribution pattern occurs in the ECL-cells when they pass from a state of hyperplasia to that of a genuine neoplasia. In neuroblastomas, a triploid (i.e. aneuploid) DNA pattern is part of an algorithm capable of predicting a 96% survival rate, whereas a diploid/tetraploid (i.e. euploid) DNA pattern predicts a 0% survival.

Flow cytometric DNA analysis of colorectal carcinoid

We analyzed the patterns of DNA ploidy in 31 colorectal carcinoid tumors from paraffin-embedded tissues by DNA flow cytometry and the relationship of the patterns of DNA ploidy to prognosis. Diploid DNA was found in 78% (24 of 31) of carcinoids and tetraploid in 6% (2 of 31). Five (16%) carcinoids were DNA aneuploid, and four of the patients with aneuploidy showing a near-hypertriploid pattern died during the first 5 years of follow-up. The association of aneuploidy with stage, size, and invasion of tumor was significant. However, our data indicated that DNA aneuploidy of a near-hypertriploid pattern was the most precise and reliable parameter for predicting the prognosis of colorectal carcinoid tumors.

Rectal carcinoids: the most frequent carcinoid tumor

One hundred seventy patients with gastrointestinal carcinoid tumors were treated at Ochsner Clinic from 1958 to 1990. Ninety-four rectal carcinoid tumors were diagnosed and treated during this time. Carcinoid tumors of the rectum represented the most frequent primary site (55 percent), followed by carcinoids of the ileum (12 percent), appendix (12 percent), colon (6 percent), stomach (6 percent), jejunum (2 percent), pancreas (2 percent), and other (5 percent). One-half of rectal carcinoids were discovered during anorectal examination of asymptomatic patients. The remainder were found primarily by examination of patients for symptoms of benign anorectal conditions. The diagnosis of rectal carcinoid was made at the time of initial examination in 61 patients. This allowed definitive treatment in a single session by local excision and fulguration in 48 patients. The remainder were treated by repeat biopsy and fulguration (25 patients) or by transanal excision (12 patients). Overall, 85 carcinoid tumors of the rectum measuring less than 2 cm were treated by local excision and fulguration or by transanal excision, with an average five-year follow-up. There were no local recurrences. Ten patients with metastasizing rectal carcinoids averaging 4 cm were treated. All were symptomatic at presentation and fared poorly despite radical surgery. Three were alive at three years but only one survived five years. At our institution, rectal carcinoids were the most frequently detected carcinoid tumor. Small carcinoids of the rectum were adequately treated by local excision and fulguration or by transanal excision, with no local recurrence. The true incidence of rectal carcinoids is detected only with careful and complete rectal examination of the asymptomatic screening population by experienced surgeons. With more widespread screening of the well population, rectal carcinoids may become recognized as the most frequent human carcinoid tumor.