Squamous Cell Carcinoma Of Rectum Research Articles

Anal Tumor With Refractory Hypercalcemia

See related article, Dzeletovic I et al, on page e47 in CGH. See related article, Dzeletovic I et al, on page e47 in CGH. Question: A 52-year-old woman presented to the emergency department complaining of a perianal bleeding tumor confining her to bed rest. On examination, the patient was found to have a large anal exophytic condylomatous lesion involving both buttocks with cephalad extension to the vulva and labia (Figures A and B). Bleeding areas and numerous fistulous sinus tracts were evident. Her laboratory values were otherwise remarkable for hemoglobin of 6.8 g/dL. Her past medical history disclosed cervix circumcision for intraepithelial dysplasia. The patient developed nausea, vomiting, disorientation, and hallucinations. A marked severe acute hypercalcemia developed within 24 hours (serum calcium level from 10 to 17.2 mg/dL), which was refractory to saline diuresis, zolendronic acid, and calcitonin. A hypercalcemia workup was performed disclosing raised parathyroid hormone–related protein (PTHrP) and low active vitamin D3 [1-25(OH)2VD3] plasma levels. The metastatic workup, including computed tomography of the head, chest, and abdomen, as well as pelvic magnetic resonance imaging (MRI), was unremarkable apart from a potential local invasion of the coccyx by the tumor and enlarged bilateral inguinal lymph nodes (Figure C). What was the cause of the refractory hypercalcemia and why did calcium levels continue to rise despite aggressive medical management? Look onpage 2025for the answer and see the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. The patient was urgently taken to the operating room for a wide perineal dissection and an en-block tumor and partial coccygeal resection. After surgery, her calcium levels normalized. Histology revealed an invasive squamous cell carcinoma with positive margins arising in a giant anal condyloma acuminatum. Grade III anal intraepithelial neoplasia was also present. Consequently, she underwent radical surgery and chemoradiotherapy. To our knowledge this is the third reported case1Teo M. Dhadda A. Gunn J. Paraneoplastic hypercalcaemia in squamous cell carcinoma of the anus: first reported case.Clin Oncol (R Coll Radiol). 2008; 20: 718Abstract Full Text Full Text PDF PubMed Scopus (8) Google Scholar, 2Hernandez J.M. Shibata D. Paraneoplastic hypercalcemia caused by an invasive squamous cell carcinoma arising from a giant anal condyloma acuminatum.Int J Colorectal Dis. 2009; 24: 359-360Crossref PubMed Scopus (3) Google Scholar of hypercalcemia of malignancy caused by squamous cell carcinoma arising in a giant anal condyloma acuminatum. Moreover, it is the first case with refractory hypercalcemia requiring urgent tumor excision. Giant condyloma acuminatum of the anogenital tract has a 30% rate of malignant degeneration. Identification rate of human papilloma virus (HPV) DNA in invasive anal cancer ranges from 50–95%. Almost 90% are HPV subtype 16, 7% HPV 18, 6% HPV 33, 1% HPV 31, and 2% untyped. A few studies have shown an obvious progression of anal intraepithelial neoplasia to invasive carcinoma in HPV-positive patients.3Frisch M. Glimelius B. Van den Brule A.J.C. et al.Sexually transmitted infection as a cause of anal cancer.N Engl J Med. 1997; 337: 1350-1358Crossref PubMed Scopus (575) Google Scholar We observed positive endonuclear hybridization sign for HPV DNA-subtypes 31/33 in many superficial squamous cells and koilocytes of the specimen (Figure D). The most important mechanisms involved in hypercalcemia of malignancy are (1) secretion of PTHrP (It is the leading mechanism in most cases). The gene encoding PTHrP exists in the short arm of chromosome 12 and is expressed at low levels in many normal tissues including keratinocytes. Poorly differentiated keratinocytes produce the largest amount of PTHrP. (2) Direct osteolytic metastases with release of local cytokines (in our case—coccygeal invasion) and (3) secretion of 1,25-dihydroxyvitamin D (1,25[OH]2D3; calcitriol). There are no published guidelines for selecting among supplementary modalities in the management of refractory hypercalcemia. The exact mechanism should be seriously taken into account for tailoring a treatment regimen for patients who have had a suboptimal response to initial therapy with bisphosphonates. Human Papillomavirus–Related Rectal Squamous Cell Carcinoma in a Patient With Ulcerative Colitis Diagnosed on Narrow-Band ImagingClinical Gastroenterology and HepatologyVol. 8Issue 5PreviewA 57-year-old woman presented with an 8-year history of chronic ulcerative colitis (CUC). She had received treatment with prednisone, and was maintained in clinical remission with 6-mercaptopurine. She subsequently developed steroid refractory symptoms and hence was given infliximab. Surveillance colonoscopy revealed a subtle erythematous flat lesion in the distal rectum, not contiguous with the dentate line (FigureA). Examination with narrow-band imaging (NBI) revealed a depressed lesion with an irregular ulcerated border, loss of the normal mucosal pit-pattern, and microvasculature (FigureB). Full-Text PDF

Carcinoma espinocelular de reto: relato de caso

O Carcinoma Espinocelular de Reto é entidade extremamente rara e seu comportamento biológico permanece desconhecido. O tratamento pode variar entre radio e quimioterapia isoladamente ou complementar ao tratamento cirúrgico. Relatamos caso de carcinoma espinocelular de reto superior, tratado com radio e quimioterapia, com regressão total da lesão.

Squamous Cell Carcinoma of the Rectum: Report of Two Cases

Squamous cell carcinoma of the rectum is extremely rare. Herein we report two cases of rectal squamous cell carcinoma. Case 1 was a 44-year-old Korean female presenting with abdominal pain and rectal bleeding for 3 months before her hospital visit. A colonoscopic examination revealed an ulcerated rectal mass 8 cm proximal to the anal verge. Chemoradiotherapy was administered following Hartmann's procedure in case 1. The patient remained alive during 19 months of follow up. Case 2 was a 43-year-old Korean female who had severe constipation for 2 months. A barium enema and computed tomography of the pelvis showed a rectal mass adherent to the sacrum. Based on the results of a colonoscopic biopsy, a diverting colostomy was performed in case 2, with no further treatment. The pathologic findings showed that both tumors were composed of oval-shaped cells with abundant eosinophilic cytoplasm and intercellular bridges with keratin pearls, and thus were diagnosed as well-differentiated squamous cell carcinoma. Neither of the cases showed evidence of HPV infection. The pathogenesis of rectal squamous cell carcinoma has not been clarified. Herein we report two cases of rectal squamous cell carcinoma and briefly discuss the possible histogenesis. (Intest Res 2010;8:172-176) 󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏

HPV infection in an HIV-positive patient with primary squamous cell carcinoma of rectum

Primary squamous cell carcinoma (SCC) of the colorectum is a rare malignancy of unknown etiology and pathogenesis. We report a case of primary SCC of the rectum. A 55-year-old man with a rectal tumor and human immunodeficiency virus (HIV) infection was referred to our hospital. Histopathology of biopsy specimens showed characteristics of SCC. We diagnosed the patient as having primary moderately differentiated SCC of the rectum according to the criteria proposed by Cooper. Human papillomavirus (HPV) DNA was amplified by polymerase chain reaction analysis of unfixed tumor biopsy specimens. In addition, no p53 overexpression or nuclear staining of retinoblastoma protein (Rb) was observed in neoplastic cells by immunohistochemical staining. We suggest from our case that HPV infection following the inactivation of the cellular tumor suppressor Rb and the immune suppression induced by HIV infection play an etiologic role in the pathogenesis of rectal SCC, consistent with the well-established concept of HPV-associated anal carcinogenesis.

Human Papillomavirus–Related Rectal Squamous Cell Carcinoma in a Patient With Ulcerative Colitis Diagnosed on Narrow-Band Imaging

Human Papillomavirus–Related Rectal Squamous Cell Carcinoma in a Patient With Ulcerative Colitis Diagnosed on Narrow-Band Imaging

Chemo‐radiotherapy: an alternative to surgery for squamous cell carcinoma of the rectum – report of six patients and literature review

Since 1943 [1], only 45 patients of squamous cancer of the rectum have been reported in the published reports and the largest series to date consists of 12 patients. Reports suggest that the primary treatment is surgical resection but, in the light of nonsurgical advances in the treatment of anal squamous cell carcinoma (SCC), we present a review of the literature and report six patients treated by chemoradiation therapy (CRT). A literature search was undertaken using the keywords squamous cell, epidermoid, basaloid and cloacagenic and cancer of rectum and colon to provide evidence for this discussion from studies of surgery, radiation therapy and CRT in rectal SCC. A prospective database of the Mount Vernon Cancer Centre, UK was searched from 1995 to 2005 for patients diagnosed with pure SCC of the rectum. Six patients with histologically confirmed primary SCC of the rectum were treated with primary combination chemo-radiotherapy according to protocols used for SCC of the anal canal over a 15-year period. Surgery was avoided in four, and they remain disease-free on follow-up. Primary CRT, as currently utilized in anal cancer, can be extended to primary SCC of the rectum.

Metachronous squamous‐cell carcinoma of the colon and treatment of rectal squamous carcinoma with chemoradiotherapy

Rectal squamous-cell carcinoma is a rare tumour with an incidence of less than 1 per 1000 cases. We report such a case treated with chemoradiotherapy. The patient developed a metastasis in the spleen and a further squamous tumour in the right colon, both of which were successfully resected. No histological evidence of recurrent rectal tumour has been found. Two years following presentation, the patient remains disease-free although symptomatic from a radiotherapy-induced stricture of the rectum.

Unusual Complication of Salem Sump Tube

Purpose: Enteral nutrition is a major component of therapy in critically ill patients. Feeding tubes passed through the nose or mouths are commonly used to administer medications and enteral nutrition, as well as to manage post-operative ileus. We report a case of an unusual complication associated with an orogastric tube (OGT). Methods: A 45 year old man with Hepatitis C, HIV, rectal squamous cell carcinoma status post radiotherapy was electively admitted for abdomino-perineal resection because of recurrent cancer. Post operatively, he was being maintained on mechanical ventilation. He was receiving intravenous midazolam for sedation, intramuscular ketorolac for pain management and enteral nutrition via OGT for nutritional support. On day 6, the patient had a self-limited episode of hematamesis. The ketorolac was discontinued and he was put on intravenous esomeprazole. Endoscopic investigation was deferred as the patient was febrile, hemodynamically stable and had OGT aspirate revealing clear bilious fluid. The next day, he was found to have chewed through the OGT; the external piece of the tube was found outside his mouth. Radiographs confirmed the presence of the rest of the tube in the esophagus and stomach. EGD was performed. The tip of the remnant OGT was seen at 24 cm in the esophagus. It was pushed into the stomach, snared and removed through an overtube. A large ulcer was noted beginning 2 cm above the gastroesophageal junction (GEJ) and extending into the cardia of the stomach. A visible vessel was noted in the ulcer which was injected with epinephrine and cauterized using a gold probe. Results: The patient had no further bleeding episodes but succumbed to his other comorbidities the following week. Conclusion: In our case, even though the patient was intubated and sedated, he managed to chew through the OGT and swallow the tube remnant. This case highlights the point that care must be taken to prevent damage to the OGT by placing a bite block or oral airway, despite the fact that the patient might be mechanically ventilated and sedated. Another important point to note is that even though the OGT had been in place for a short duration prior to endoscopic evaluation, this patient had developed a large ulcer at the GEJ along the course of the tube. While NSAID administration may have played a significant role in causing the ulcer, the case nonetheless emphasizes the importance of prescribing proton pump inhibitors to critically ill patients to protect against GI bleeding, particularly in patients with additional risk factors for mucosal injury.

Treatment of primary rectal squamous cell carcinoma by primary chemoradiotherapy: Should surgery still be considered a standard of care?

Rectal squamous cell carcinoma is a rare tumour accounting for only 0.25% of all rectal carcinomas, yet it carries a significant mortality and morbidity. Radical surgery has been advocated as the primary treatment modality with or without adjunctive therapies despite the proven benefits of primary chemoradiotherapy for squamous cell carcinoma (SCC) of the anus. This report describes 7 cases of rectal squamous cell carcinoma from a single institution over a four-year period, treated with primary chemoradiotherapy. All patients demonstrated significant tumour regression, and surgery to the primary tumour was avoided in all but one of these cases. Primary chemoradiotherapy can achieve excellent local control for rectal squamous cell carcinoma with surgery employed only for unresponsive or recurrent tumours.

Laparoscopic Ultralow Anterior Resection with Colonic J-pouch-Anal Anastomosis

Optimal treatment of mid to distal rectal cancers includes total mesorectal excision for oncologic clearance and, where reanastomosis is feasible, a colonic J-pouch-anal anastomosis improves bowel function. There is recent interest in performing an ultralow anterior resection laparoscopically. A technique is described that includes specimen extraction through the eventual routine defunctioning colostomy or ileostomy site. Consecutive unselected patients who underwent laparoscopic ultralow anterior resection were recruited. Patients with adenocarcinoma underwent preoperative endorectal ultrasound to individualize for neoadjuvant chemoradiotherapy, based on local extent and lymph nodes seen. The operative procedures were as shown in the video. Posterior dissection along the "total mesorectal excision plane" included incision of Waldeyer's fascia. Bowel continuity was restored by an intracoporeal double-cross stapled colonic J-pouch-anal anastomosis, but where not possible a coloplasty with pull-through handsewn coloanal anastomosis was performed. Laparoscopic ultralow anterior resection was performed on 55 patients (35 men; median age, 63 (range, 33-90) years) from March 2004 to October 2006. The median body mass index was 26.3 (19-38); 14 patients (25 percent) had a body mass index >30. Ten patients (18 percent) had an American Society of Anesthesiologists' classification of III. The indications were adenocarcinoma (n = 51), squamous-cell carcinoma of rectum (n = 1), dermoid tumor of mesorectum (n = 1), large villous adenoma (n = 1), and carcinoid with local lymph node metastases (n = 1). The adenocarcinomas were a median distance of 6 (3-12) cm from the anal verge. Neoadjuvant radiotherapy was given in 12 patients (24 percent) who had preoperative endoanal ultrasound findings of tumor extension beyond the muscularis propria and chemoradiotherapy in 7 (14 percent) of these patients where the tumor was more bulky and fixed. Laparoscopic ultralow anterior resection was completed at a median 180 (90-405) minutes, with 53.5 (2-2250) ml of blood loss, and the specimen was extracted through a 4.5 (3.5-11) cm wound. The latter included three cases (5 percent) that were converted. Significant adhesiolysis was required in 29 patients (52.7 percent) because of previous operations. The histologic grading or the adenocarcinoma patients were: Stage I, n = 14; Stage II, n = 23; Stage III, n = 11; Stage IV, n = 3. Of those who underwent curative resection (Stages I-III), the distal resection margin was 2.9 +/- 0.7 cm (mean +/- standard error) and the radial resection margins were at least 2 mm in all patients. The level of the coloanal anastomosis was a median 3.5 (0-4.5) cm from the anal verge; a coloanal pull-through anastomosis was required in one patient who had a distal cancer. The ileostomies functioned and patients tolerated free fluids at a median of two (1-9) days, and the median postoperative hospital stay was seven (3-22) days. At a median follow-up of 14 (2-33) months, none of the adenocarcinoma patients who had undergone curative resection had recurrences. Four patients (8 percent) had postoperative complications that required operative/invasive intervention (anatomotic leak n = 1, proximal bowel ischemia n = 1, port site hernia n = 1, pelvic collection n = 1). Four other patients had smaller pelvic collections that resolved with antibiotics; pelvic collections were associated with advanced stage of cancer (P = 0.047). Discharge was delayed by acute gastric distension in 11 patients; the latter was associated with poorer American Society of Anesthesiologists' risk classification (P = 0.035). Erectile dysfunction occurred in ten men, and this was associated with adjuvant chemoradiotherapy (P = 0.042). One patient (2 percent) had persistent urinary retention that required catheterization at latest follow-up. The ileostomy had been closed in 50 patients, and at last follow-up, the median stool frequency was two (1-8) bowel movements per day. Laparoscopic ultralow anterior resection could be offered routinely and completed safely in Western populations, where obesity and adhesions from previous abdominal surgery is common. A laparoscopic technique readily allowed visual identification of the autonomic nerves in the abdomen over the aorta, which could then be followed down into the pelvis. If the pelvis was deep, inversion of the 30 degrees laparoscope in the "upside down" position fascilited incision of Waldeyer's fascia. This brought the rectum proximally and anteriorly, aiding with the laparoscopic stapler transection of the distal rectum, especially if the cancer was distal, the patient was obese, and the pelvis was narrow. Extraction of the specimen at the eventual defunctioning stoma site reduced the incisions required. Preoperative chemoradiotherapy may have a role in postoperative male sexual dysfunction. Further randomized, controlled studies that include assessing five-year cancer survival/recurrence, pelvic nerve dysfunction, and bowel function are needed before laparoscopic ultralow anterior resection becomes widely accepted.

Squamous-Cell Carcinoma of the Rectum: A Rare but Curable Tumor

This study was designed to evaluate one institution's experience with treatment outcomes for rectal squamous-cell carcinoma. Using our prospective Colorectal Database, we identified patients diagnosed with rectal squamous-cell carcinoma at our institution between 1983 and 2005. Pathology was rereviewed, tumor immunophenotype was compared to control cases of anal squamous-cell carcinoma and rectal adenocarcinoma, treatment modalities and outcomes were analyzed. Twelve patients were identified (10 females median age, 58 years). Median distal extent of tumors was 7 (range, 5-8) cm from the anal verge. Treatment included chemotherapy only (n = 1), chemoradiation only (n = 2), induction chemotherapy followed by chemoradiation and surgery (n = 2), chemoradiation followed by surgery (n = 5), and surgery followed by chemoradiation (n = 2). The chemotherapy regimen was 5-fluorouracil-based. Radiotherapy total dose was 50.4 Gy (1.8 Gy/day, daily x 5) external iliac and inguinal nodes were not included in the radiation field. Complete clinical responders to chemoradiation (n = 2) received no further treatment. All seven partial responders underwent surgery; six had complete pathologic response; nodal status in two of six was unknown because they had local excision. Immunophenotypical analysis showed similar keratin expression profile between rectal squamous-cell carcinoma (n = 5) and rectal adenocarcinoma (n = 5), which is different from anal squamous-cell carcinoma (n = 10). All patients were alive without evidence of disease at follow-up (median follow-up, 2.6 (range, 0.5-16) years). Our data suggest that most patients treated with upfront chemoradiation therapy followed by surgery did well. Sphincter-preserving surgery is usually feasible. Clinical judgment of tumor response after chemoradiation is not completely reliable. Immunohistochemistry suggests a common cellular origin for rectal squamous-cell carcinoma and rectal adenocarcinoma, which is different from anal squamous-cell carcinoma.

Role of Human Papillomavirus in Squamous Cell Metaplasia-Dysplasia-Carcinoma of the Rectum

Primary colorectal squamous cell carcinoma (SCC) and squamous dysplasia are uncommon and little is known about their pathogenesis. Most have been reported in association with ulcerative colitis and other chronic disease states. Although cervical and anal SCC have been strongly linked to human papillomavirus (HPV) infection, the role of HPV in rectal squamous carcinoma has not been well-examined. We evaluated 3 cases of primary rectal SCC for the presence of high-risk HPV by immunohistochemistry for p16(INK4A), in situ hybridization, and polymerase chain reaction. HPV type 16 was detected by polymerase chain reaction in all cases. In addition, all cases exhibited diffuse strong reactivity for p16(INK4A) and punctate nuclear staining by Ventana HPVIII in situ hybridization. The presence of HPV 16 in all three cases suggests that high-risk HPV infection is a risk factor for rectal SCC, particularly in patients with underlying chronic inflammatory disease processes or altered immune status. Further studies are warranted to determine if SCC occurring more proximal in the colon are also HPV-dependent or occur via another, HPV-independent pathway.

Aggressive treatment of metastatic squamous cell carcinoma of the rectum to the liver: a case report and a brief review of the literature

BackgroundRectal squamous cell carcinoma (SCC) is a rare tumor. The incidence of this malignancy has been reported to be 0.25 to 1 per 1000 colorectal carcinomas. From a review of the English literature 55 cases of SCC of the rectum have been published. In this study we report a rectal metastatic SCC to the liver, discussing the efficacy of aggressive adjuvant and neo-adjuvant therapies on survival and prognosis.Case presentationA 39-year-old female patient with a pure SCC of the rectum diagnosed endoscopically is presented. The patient underwent initially neoadjuvant chemo-radiotherapy and then abdominoperineal resection with concomitant bilateral oophorectomy and hysterectomy, followed by adjuvant chemo-radiotherapy. Five months after the initial operation liver metastasis was demonstrated and a liver resection was carried out, followed by adjuvant chemotherapy. Eighteen months after the initial operation the patient is alive.ConclusionAlthough prognosis of rectal SCC is worse than that of adenocarcinoma, an aggressive therapeutic approach with surgery as the primary treatment, followed by combined neo- and adjuvant chemo-radiotherapy, may be necessary in order to improve survival and prognosis.

Primary squamous cell carcinoma of the rectum in a patient on immunosuppressive therapy

Primary squamous cell carcinoma of the rectum is a rare tumour.1–11 The diagnosis of squamous cell carcinoma rests on the exclusion of metastases from other organs, proximal extension of carcinoma arising from the anal canal and squamous-lined fistulous tracts. Here we report an uncommon presentation of rectal squamous cell carcinoma in a woman on long-term immunosuppressive therapy.

Squamous cell carcinoma of the rectum: a case report and review of the literature

Squamous cell carcinoma of the colon and rectum are extremely rare neoplasms. Many questions regarding their histogenesis and biological behaviour remain unanswered. Surgery is the most effective therapy, and adjuvant chemotherapy and radiotherapy should be considered, especially for node-positive patients. We present a patient with squamous cell carcinoma of the middle rectum who underwent abdominoperineal resection and postoperative adjuvant chemotherapy. The pertinent literature is reviewed.

Squamous cell carcinoma complicating idiopathic inflammatory bowel disease

Squamous cell carcinoma of the colon and rectum, originating proximal to the transitional zone, is a rare complication of idiopathic inflammatory bowel disease (IIBD). To date there are only 15 single case reports of such an occurrence. This carcinoma develops more commonly in females and in patients with pancolonic disease of more than 8 years' duration. The rectum is affected in two thirds of the cases. Squamous cell changes, in the vicinity of the primary adenocarcinoma, are present in 27% of cases. The carcinoma is in a pathologically advanced stage in one third of the cases. Colectomy is the main therapeutic modality. Survival following surgical resection ranged from 7 months to 21 years. We present an additional case of rectal squamous cell carcinoma (SCC) complicating chronic ulcerative colitis in a 33-year-old woman who had the disease for 15 years. Multiple biopsies of a gross lesion located 5 cm above the dendate line were consistent with invasive basaloid cell carcinoma. The patient received 5-FU, mitomycin C, and radiotherapy prior to a proctocolectomy and ileostomy. The only histopathologic finding at pathologic review of the surgical specimen was severe squamous dysplasia.

A test to detect clusters of disease

SUMMARY A test is given to detect clustering in disease incidence or mortality data. The test statistic is the mean distance between all pairs of disease cases. Its null mean and variance and its asymptotic normality are derived under assumptions that accommodate differences in population distribution among demographic subgroups at different disease risk. The test is illustrated on 63 cases of anal and rectal squamous cell carcinoma in San Francisco during 1973-1981. Patterns of disease incidence and mortality over time, space, or occupational categories can provide clues to the cause of the disease. An aetiologic agent can produce a spatial, temporal or occupational cluster of disease cases. It is seldom difficult to detect clusters of rare diseases like angiosarcoma of the liver among men occupationally exposed to polyvinyl chloride. However more common diseases present two problems. First, clusters may be obscured by the scattered occurrence of cases unrelated to the cause of the clusters. Secondly, clusters may be produced by factors unrelated to the disease process, such as variations in the overall population distribution, or variations in the distributions of demographic subgroups at high disease risk. It is therefore useful to have a method for detecting clusters that will adjust for such factors. Previous tests for clustering, for example, Pinkel & Nefzger (1959), Knox (1964), Mantel (1967), are not satisfactory for the study of chronic disease such as cancer. Those tests are designed to determine whether cases are clustered both in space and in time simultaneously. However, cases of chronic disease caused by a spatially localized agent may be close in space, but they are unlikely to be close in time, because of long and variable time periods between exposure and diagnosis. Thus there is need for alternative methods to detect spatial clusters in regional disease incidence or mortality data. Consider the set X = {xl,... , XK } of points called census tracts, with Nk cases of disease, called cancer, in tract Xk. Under the hypothesis Ho of no clustering, the Nk are independent Poisson variables, with the mean of Nk proportional to the population size ek in tract xk:

Stromal reaction to neoplasia: colonic carcinomas.

The stroma and stromal reaction in the normal colon and in 14 different colonic tumors were studied by electron microscopy. Elastosis is a significant part of the stromal reaction to colonic adenocarcinomas and rectal squamous cell carcinomas. Two carcinoid tumors elicited no significant elastosis. In some of the adenocarcinomas, small muscular arteries close to neoplastic tissue developed massive elastosis of the media. This may indicate that the elastosis is due to stimulation of nonneoplastic stromal cells by some unknown neoplastic factor or factors.

Squamous Cell Carcinoma of Rectum

Squamous Cell Carcinoma of Rectum