Colorectal mesenchymal tumors - from smooth muscle tumors to stromal tumors

Colorectal mesenchymal tumors are rare. Therefore, distinguishing between gastrointestinal stromal (GIST) and smooth muscle tumors is important. This study aimed to delineate the immunophenotype and prognostic factors of 75 colorectal mesenchymal tumors. Fifty-three GIST and 22 smooth muscle tumor specimens were included from 1986 to 2007. Forty of 53 GIST were initially diagnosed as smooth muscle tumors and re-diagnosed as CD117 (+) GIST. Immunohistochemical studies were performed with antibodies of CD117, CD34, smooth muscle actin (SMA), desmin, S-100, Ki-67 and PCNA for clinicopathologic and prognostic correlation. In comparison, colorectal GIST exhibited a larger tumor size (P<0.001), higher mitotic count (P<0.001), higher cellularity (P<0.001), less spindle cell type (P=0.004), higher nuclear pleomorphism (P=0.004), and a higher NIH risk (P<0.001) than that of smooth muscle tumors. Positive immunoreactivities of GIST to a panel of antibodies were 88.6% to CD34, 28.3% to SMA, 1.8% to S-100 and 15.1% to desmin. For 75 mesenchymal tumors, survival analyses revealed that older patients (P=0.006), with a large tumor size (P<0.001), high mitotic count (P<0.001), increased NIH risk (P<0.001), non-spindle cell type (P<0.001), high cellularity (P=0.015), high cell pleomorphism (P<0.001), positive Ki-67 (P<0.001), high PCNA (P<0.001) and GIST (P=0.001) had a shorter disease-free survival than that of comparative groups. When the analyses concentrated on 53 GIST, the cell type and cellularity were no longer viable prognostic factors. The tumor mitotic count was the only independent prognostic factor for either mesenchymal tumors or GIST. In conclusion, GIST exhibited heterogeneous characteristics and was significantly larger, more mitotic and a poorer prognostic factor than smooth muscle tumor. The mitotic count is still the most valuable prognostic factor for colorectal mesenchymal tumors after KIT.     

Neuroendocrine tumors

Neuroendocrine tumors comprise a broad family of tumors, the most common of which are carcinoid and pancreatic neuroendocrine tumors. The NCCN Neuroendocrine Tumors Guidelines discuss the diagnosis and management of both sporadic and hereditary neuroendocrine tumors. Most of the recommendations pertain to well-differentiated, low- to intermediate-grade tumors. This updated version of the NCCN Guidelines includes a new section on pathology for diagnosis and reporting and revised recommendations for the surgical management of neuroendocrine tumors of the pancreas.     

Bugging tumors

The effects of bacteria on patients with cancer have been observed for at least two centuries. Recent studies in animal models of cancer have shown efficacy of both anaerobic bacteria such as Clostridia and Bifidobacteria and facultative anaerobes such as Salmonella. In this issue of Cancer Discovery, Flentie and colleagues have identified five Salmonella promoters that are specifically stimulated by cancer cells as well as by acidic pH, a property of most tumors. One of these promoters (STM1787) was linked to a Shiga toxin gene and inserted in a wild-type Salmonella typhimurium strain, which showed in vivo antitumor efficacy. Approaches to further improving the efficacy of S. typhimurium with the use of tumor-targeting mutations are discussed. Because the barriers to efficacy of standard therapy of cancer appear to be opportunities for bacterial cancer therapy, the future of bacterial therapy of cancer appears bright.     

Hematologic tumors

Development of cytarabine and daunorubicin has made a cure for acute myeloid leukemia (AML) possible. Current first line chemotherapy is a combination of idarubicin plus cytarabine. Acute promyelocytic leukemia has the highest cure rate among AML due to the introduction of ATRA. Current first line chemotherapy for advanced Hodgkin's lymphoma is ABVD, based upon results of a prospective randomized study comparing MOPP, ABVD and MOPP/ABVD. CHOP has been frequently selected as first line chemotherapy for advanced non-Hodgkin's lymphoma, based upon results obtained in a phase III study that compared CHOP versus second and third generation combinations.     

Parathyroid tumors

Opinion statement Parathyroid tumors causing primary hyperparathyroidism are common and often remain undiagnosed, despite that the diagnostic work-up is uncomplicated in most patients. The patients often do not receive the appropriate curative treatment, which is surgical. Recent studies show that surgery is beneficial in patients with mild asymptomatic disease, especially in the reversal of bone disease, neuropsychologic symptoms, and dyslipoproteinemia. All patients with the disease deserve a referral to an endocrine surgeon for discussions regarding surgical intervention. Minimally invasive techniques performed in the ambulatory setting have evolved rapidly and show an extraordinary high success rate, low-morbidity rate, and are likely to become the standard treatment for most patients with primary hyperparathyroidism.     

Pineal tumors

From 1972–1985, 30 patients with pineal area tumor have been treated with combinations of surgery and irradiation, no patient receiving chemotherapy as a primary recommendation. Patients ranged between 3 and 69 years of age, 18 were male and 12 female. In 18 patients a tissue diagnosis was made initially, 14 patients required shunts before definitive management and in 8 of the 14 tissue diagnosis was made at the same time. Eight patients had no surgical intervention at any time. Patients who have received irradiation have had whole brain irradiation, local field irradiation, or craniospinal irradiation. Two elderly patients died rapidly of their malignant processes before definitive treatment could be given. Only one patient with a non neoplastic lesion was seen. This was a bleed from an AVM with no underlying tumor. One patient with a pineocytoma was not irradiated. Overall, two-thirds of our patients are alive 5 to 15 years after treatment. There has been no surgical mortality and minimal morbidity from biopsy. Late effects of treatment include one patient with mild hearing loss and three patients with endocrinopathies amenable to medical treatment. We believe that tissue diagnosis allows optimal field design and dose recommendations to be made by the radiotherapist in addition to defining prognosis. In our experience, endodermal sinus tumor and pineoblastoma are highly malignant, and in view of their poor prognosis with conventional management consideration of more radical treatment with a possible role for chemotherapy is suggested.     

Carcinoid tumors

The authors carried out a retrospective study of 32 patients (23 M, 9 F) with carcinoid tumors who were diagnosed and treated at Harlem Hospital Center, New York, from 1967 to 1988. All the patients were black and the commonest sites were the ileum (28.1%), rectosigmoid and rectum (21.9%), and the appendix and lung (15.6% each). Metastasis correlated with site, size, and depth of the primary tumor and occurred in 12 patients (38%), most frequently to the regional lymph nodes and liver. Carcinoid syndrome developed in 12.5% (3 F, 1 M). Surgical resection for cure or palliation was the mainstay of treatment. Overall 5 year survival rate was 66%, and for those with metastases was 0%. The poorer survival rates are probably related to the socioeconomic status of our patient population. The only observed racial difference compared to other series is the preponderance of males, and the disproportionately higher ratio of females with the carcinoid syndrome.     

Carcinoid tumors

Carcinoid tumors can present a difficult diagnostic and therapeutic dilemma. Despite their reputation as indolent tumors, they frequently metastasize and can cause significant symptomatology. The only curative therapy remains surgical resection. The prognosis and treatment of carcinoids vary based on location and histology, and therapy must be tailored to each patient.     

Ependymal tumors

Opinion statement Ependymal tumors are rare malignancies that arise from the cells that line the ventricles and central canal of the spinal cord. Although they are more common in children, adults may also be effected by ependymal tumors. Prognosis is dependent on tumor location, histology, especially for myxopapillary tumors that tend to occur in the lumbar spine, extent of surgical resection, and stage of disease. Standard therapy consists of complete resection when feasible. The exact role of adjuvant radiotherapy in patients with radiographically confirmed complete resection is poorly defined. Patients with known residual disease may benefit from local radiation therapy, but the extent of radiation field and total dose are controversial. Even in patients treated with involved field radiotherapy, most relapses occur within the original tumor bed, thus local control remains the biggest obstacle to effective therapy. Chemotherapy has little impact against this tumor and has no role in the adjuvant setting, outside of a well designed clinical trial, with the possible exception of children younger than 5 years in an effort to delay radiation. A minority of patients may respond to one of several chemotherapy regimens at the time of recurrence, but the impact of this therapy is limited. Newer treatment strategies are needed.     

Carcinoid tumors

Opinion statement Carcinoids are rare endocrine tumors that can develop in several organs in the body. Clinically, patients can have a wide spectrum of signs and symptoms that range from incidental findings of a polyp during endoscopy to the carcinoid syndrome characterized by severe flushing, diarrhea, abdominal cramping, and life-threatening right-sided heart failure. Most carcinoid tumors are indolent but can metastasize to regional lymph nodes and to other organs, including the liver, bone, and the central nervous system. Treatment is determined by tumor location and by the presence of distant metastasis. Surgical resection of the tumor is advocated in patients with localized disease and can often be curative. Long-acting somatostatin analogs, including octreotide, octreotide long-acting repeatable, and lanreotide prolonged release, are effective in providing symptom relief in patients with the carcinoid syndrome. Patients with metastatic disease to the liver that is refractory to somatostatin treatment should be considered for hepatic artery occlusion. Overall, 5- and 10-year survival rates in patients with metastatic disease are favorable, although tumors can be resistant to most forms of medical or surgical therapy.     

Testicular tumors

Germ cell tumors of the testes represent a unique paradigm of diseases which can be cured even in extremely advanced phase. Unfortunately, this makes them unique among adult solid tumors. Seminoma and non seminoma are relatively rare with approximatively 25,000 patients in Europe per year, but numbers are increasing world wide. Different strategies are needed depending on stage and prognostic scores. Seminoma is extremely sensitive to radiation therapy and chemotherapy, while all germ cell tumors show a very good response to chemotherapy. Clinical stage I seminoma is currently treated with radiation, single course carboplatin or surveillance policy. Clinical stage I non seminoma can also be approached with different strategies such as retroperitoneal lymph node dissection, observation or one-two courses of standard chemotherapy. Stage II seminoma may be treated with either radiation or chemotherapy, while for all advanced stages chemotherapy is mandatory. Since the mid-eighties PEB (Cisplatin, Etoposide and Bleomycin) is the regimen of choice and no other schedule has proved superior in terms of efficacy. Surgery on the residual disease is crucial to the whole strategy and should be performed or attempted in all cases. Consequently, the correct treatment strategy for these tumors does not depend only on the ability of a single physician, but on a skilled team specialized in this particular tumor. Second line therapies (VeIP, PEI, TIP) can cure 25%–40% of patients, but improved strategies for resistant tumors are desperately needed. High-dose chemotherapy has shown very good results in some studies while being less impressive in others. In any case, it should remain an option for relapsing patients and could be used in some cases of upfront chemotherapy in patients with slow marker decline, but this should only be considered in referring centers.     

Desmoid tumors

Opinion statement Because of the wide variety of anatomic locations and patient factors, there is no one treatment that is appropriate for all desmoid tumors. The type of treatment depends on tumor characteristics and location, as well as patient characteristics and preferences. Desmoid tumors can be persistent and frustrating to manage because no one treatment modality offers a high likelihood of remission. Multiple modalities may be necessary in some patients. Although mortality is rare and is usually due to local complications, significant disability or morbidity can result from desmoid tumors, their treatment, and complications arising from treatment. The entire clinical picture and the patient’s preferences must be taken into account when deciding on an appropriate treatment plan. Patients with desmoid tumors are optimally managed in a multidisciplinary setting with close collaboration between surgeon, pathologist, diagnostic radiologist, radiation oncologist, and medical oncologist. When possible, surgical resection with negative margins is the preferred modality. When surgical resection with negative margins may prove disabling, surgery can be followed by postoperative radiation, although the role and efficacy of this are controversial. In locations where surgical extirpation is difficult or unfeasible, primary radiation, hormonal therapy, or chemotherapy should be considered. Familiar adenosis polyposis (FAP)-associated mesenteric lesions, sporadic tumors present without change for months or years, or tumors present in areas where progression will not present significant additional morbidity are candidates for observation only.