Chronic irradiation enteritis: its correlation with the elapsed time interval and morphological changes

Small Intestinal Adenocarcinomas Arising in Enteritis Cystica Profunda With Metaplasia: A Report of 2 Cases

Enteritis cystica profunda (ECP) is an uncommon benign condition arising after mucosal damage. We describe 2 cases of small intestinal adenocarcinomas associated with ECP at the distal ileum, one in a background of active Crohn ileitis (case 1), the other 22 years after pelvic radiation therapy (case 2). Both patients presented with small bowel obstruction and received ileocectomy. Macroscopic examination identified an indurated/strictured area in the distal ileum. Histologically, both cases showed a low-grade tubuloglandular adenocarcinoma arising in a background of chronic ischemic stricture and ECP lined by flat cuboidal cells with mild cytologic atypia resembling pancreatobiliary-type epithelium. There was no conventional dysplasia in the surface or adjacent mucosa. Immunohistochemically, both ECP with metaplasia and invasive carcinomas were diffusely positive for CK7 and CK19, while focally positive for CDX2 or CK20. Both cases showed normal wild-type p53 expression. Case 2 was also mismatch repair protein proficient, with membranous β-catenin staining, and retained nuclear SMAD4 expression. In summary, the 2 cases uniquely exhibits "enteritis-metaplasia-carcinoma" sequence, which has not been reported before. This process appears to bypass conventional dysplasia, be slow and indolent, independent of p53, APC/β-catenin, and SMAD4/TGFβ signaling pathways.

Management of Long-Term Toxicity From Pelvic Radiation Therapy

Pelvic radiation therapy is an integral component in the treatment of various gastrointestinal, gynecologic, and genitourinary cancers. As survival rates from these malignancies improve, the prevalence of toxicity secondary to pelvic radiation has increased. Gastrointestinal toxicities are the most common complications and greatly impact quality of life. Toxicities can present in acute or late stages; although symptoms may be similar during both, the management may differ. Acute toxicities represent an inflammatory reaction in response to the radiation exposure, whereas late toxicities may arise as a result of small vessel disease, ischemia, and fibrosis. Currently, there are no large clinical trials and only limited guidelines on the management of late gastrointestinal radiation toxicities. Therapy is generally approached in a stepwise manner from medical to endoscopic to surgical methods. Several endoscopic therapies, such as the treatment of radiation proctitis with argon plasma coagulation and dilation of radiation bowel strictures, may prevent the need for surgical intervention, which may be associated with high morbidity and mortality. Given that late toxicities can occur years after radiation therapy, they are often difficult to recognize and diagnose. Successful management of late toxicities requires recognition, an understanding of the underlying pathophysiology, and a multidisciplinary approach. More dedicated research could clarify the prevalence of gastrointestinal pelvic radiation toxicities, permit a better understanding of the efficacy and safety profile of current therapies, and allow for the development of novel therapeutic approaches.

[Clinicopathologic features and postoperative outcome of the radiation-induced enteritis: a retrospective study of 41 patients]

INTRODUCTION

Surgery is required in patients with symptoms of chronic radiation-induced enteritis (CRE) resistant to medical therapy. The study aimed to correlate histopathologic features of CRE to the clinical presentation and the postoperative recurrence.

MATERIAL AND METHOD

All patients with small bowel resection performed for CRE between 2006 and 2017 were studied. Histological data were retrospectively correlated to initial clinical data and to postoperative recurrence of CRE (occlusion, need for parenteral nutrition) observed during a median follow-up of 32 months.

RESULTS

Forty-one patients were studied (39 women and 2 men, median age 62 yo at time of radiation for pelvic cancer, 80% gynecologic). Median time to surgery after radiation was 3 years. Ileocaecal resections (80% of patients) removed 60cm (median length). Histologically, a diffuse obliterative arteriopathy was present in 24 (59%) patients, highly associated to amyotrophy, villous atrophy and ulceration observed in 66, 63 and 34% of patients respectively (P<.05). Diffuse arteriopathy was uncorrelated with patient's age and vascular risk factor (tobacco, diabetes, hypertension, dyslipidemia). Median time to surgery after radiation was longer in patients presenting with obliterative arteriopathy (13 years vs. 2.6 years, P=0.0002). During follow-up, half of the patients had a recurrence of CRE, uncorrelated to the arteriopathy.

CONCLUSION

Radiation-induced enteritis requiring late surgery after radiation presented histologically with a diffuse obliterative arteriopathy and ischemic features. In our center, half of the patients were cured by surgery. The arterial injury was not a risk factor for postoperative recurrence.

Ischemic enterocolitis and its differential diagnosis

Ischemia is a common type of gastrointestinal injury that can be clinically misdiagnosed due to its often mild and transient clinical presentation as well as a tendency to masquerade as other disorders. A wide range of etiologies can contribute to the development of ischemia. These include hypovolemic states, systemic diseases such as vasculitis and hypercoagulable states, mechanical obstruction, therapeutic drug effects, infection, and a host of other diseases. An accurate diagnosis of ischemia relies on a strong clinical suspicion in combination with endoscopic and pathologic findings. Most cases show histologic features that are diagnostic of ischemia, but do not point to a specific differential diagnosis, whereas the cause of ischemia can be recognized or suspected based on careful review of vascular changes in others. This review is focused on providing an overview of ischemic enterocolitis and its differential diagnosis.

Radiation-induced rectal complications are not influenced by age: a dose fractionation study in the rat

Radiation-induced complications of the rectum are an important dose-limiting factor in radiotherapy of pelvic malignancies. In general, animal studies demonstrated no differences in acute and late normal tissue toxicity with age, but little is known about rectal complications in relation to age. For this purpose, an extensive histological and dose fractionation study was carried out on the rectum of young (12 weeks) and older (77-80 weeks) rats. In this paper, the results of dose fractionation are presented in relation to age at the time of irradiation. Young and older animals were irradiated with single and fractionated doses. After irradiation, rectal complications could lead to occlusion and stenosis, eventually resulting in the clinical symptoms of a megacolon and a possible fistula. For each dose group, cumulative survival rates were obtained with Kaplan-Meier analysis, from which dose-effect curves and the associated LD(50) values for a megacolon/fistula were calculated. The majority of responders died between 8 and 24 weeks after irradiation, irrespective of age. For both age groups, only the fractionation data showed a reduction in the mean latency with increasing dose. In the older age group, 39% of the responders developed a fistula compared to 26% for the younger animals. The LD(50) values increased from around 30 Gy after single doses to nearly 65 Gy after 10 fractions. The increases in LD(50) values with the number of fractions were independent of the age of the rats. For each of the dose fractionation schedules, log-rank testing indicated no significant differences in cumulative survival rates between younger and older animals (P > 0.10). The high alpha/beta ratios obtained for both the young and older animals strongly suggested that the late rectal complications were a consequence of early epithelial injury. Associated histological findings indicated that blood vessel damage, which was already evident at a high incidence at 4 weeks after irradiation, could also play a significant role in the occurrence of consequential late injuries. In conclusion, data obtained for the latent period of rectal occlusion, for the dose-effect curves, for the log-rank testing of cumulative survival rates, and for the alpha/beta ratios strongly support the hypothesis that the incidence of radiation-induced rectal complications is independent of age. Late rectal complications could be a consequence of radiation-induced acute injury.

Effect of age on radiation-induced early changes of rat rectum. A histological time sequence

BACKGROUND AND PURPOSE

Radiation treatment of the elderly (> 75 years) is often modified due to an assumed decrease in normal tissue tolerance in this age group. Since more radiobiological data concerning normal tissue toxicity as a function of age are needed, a histological study of age-related radiation changes of the rectum was performed.

MATERIALS AND METHODS

The rectum of young and old female Wistar rats (12 and 78 weeks, respectively) was irradiated with single doses of 22 and 39 Gy. The field size was 1.5 x 2.0 cm. The animals were sacrificed at 1, 2, 4 and 10 weeks after treatment. To evaluate radiation damage, 12 histological parameters were scored in four areas of the rectum. A total radiation injury score was calculated. The number of proliferative epithelial cells was evaluated by 5-bromo-2'-deoxyuridine labeling.

RESULTS

Some age-related histological differences were observed; especially, the incidence of ulceration and vascular occlusion was higher in the older group. In the low dose group of the older animals, 60% showed ulceration, which was 0% for the young low dose animals. Severe vascular changes occurred early and were more extensive in older animals (4 weeks) than in the younger group (10 weeks). In the area adjacent to the treatment field, cell proliferation increased significantly in older rats at 1 week after 22 Gy, which did not occur in the young group.

CONCLUSIONS

Discrete radiation-induced histological differences were observed between the rectum of young and old Wistar rats, especially in the development of ulceration and vascular changes. Although the survival of these Wistar rats in earlier studies was not affected by age, the impact of the observed histological differences for their importance in the long-term is currently being investigated.

Apoptosis, proliferation, bax, bcl-2 and p53 status prior to and after preoperative radiochemotherapy for locally advanced rectal cancer

PURPOSE

To investigate the relationship between apoptotic cell death, proliferative activity, and the expression of apoptosis regulating proteins in rectal cancer prior to and after radiochemotherapy.

MATERIALS AND METHODS

In 32 patients dispositioned to receive preoperative radiochemotherapy for locally advanced rectal carcinoma, pretherapy biopsies and the final resected specimen after radiochemotherapy were available for analyses. Apoptotic cells were identified and quantified using in situ end labeling (ISEL) technique. The expression of the bax protein was assessed immunohistochemically. Additionally, double immunostaining was performed for apoptotic cells and bax expression. The proliferative activity was determined by immunohistochemical assessment of the Ki67 (MIB-1) and the proliferating cell nuclear antigen (PCNA). p53- and bcl-2 expression was analyzed immunohistochemically. A clinical-to-pathologic downstaging after radiochemotherapy was achieved in 25 of 32 patients (78%). During follow-up, tumor recurrence was observed in six cases. In one case, no residual tumor was detected after radiochemotherapy.

RESULTS

After radiochemotherapy, the apoptotic index increased significantly in almost every case examined. In contrast, the proliferative activity was significantly decreased in resected specimens as compared to biopsies. Bax immunostaining was detected in 12/31 (39%) biopsies and in 26/31 (84%) resected specimens. In the resected specimen, significantly more apoptotic cells that were bax-positive were found than in biopsies. Bcl-2 immunostaining occurred in 15/31 biopsies and 12/31 resected specimens, respectively. Tumors that were immunohistochemically negative for p53 (20/31 [65%]) generally exhibited a higher apoptotic index and a high expression level of bax than p53-positive tumors (11/31 [35%]). However, we did not find any correlation between the (pre- and post-therapeutic) rate of apoptosis or the level of bax expression and the degree of clinical-to-pathologic downstaging or the frequency of tumor recurrence.

CONCLUSION

Our results indicate that radiochemotherapy is associated with an increase in bax expression and also in apoptotic cell death. The observation of higher rates of apoptosis and bax in p53-negative tumors suggests that p53 might be a possible regulating factor of apoptosis in rectal cancer.