Cancer cells differ from normal cells in many ways that allow them to grow without control and become invasive. This means that, while normal cells mature in very different cell types with specific functions, cancer cells do not. This is one reason why, contrary to normal cells, cancer cells continue to divide without stopping.
In addition, cancer cells can ignore signals that normally tell cells to stop dividing or begin a process known as programmed cell death, or apoptosis, which uses the body to get rid of cells that are not Necessary.
Cancer cells may have the ability to influence normal cells, molecules, and blood vessels around and feed the cells of a tumor — an area known as the microenvironment. For example, cancer cells can induce normal cells near them to form blood vessels that supply oxygen and nutrients needed for tumors to grow. These blood vessels also remove the waste products from the tumors.
Cancer cells are often also able to evade the immune system, a network of organs, tissues, and specialized cells that protect the body from infections and other illnesses. Although the immune system ordinarily removes damaged or abnormal cells from the body, some cancer cells are able to “hide” from the immune system.
Tumors can also use the immune system to stay alive and grow. For example, with the help of some immune system cells that ordinarily impedes an uncontrolled immune response, cancer cells can actually make the immune system not destroy cancer cells.
How cancer appears
Cancer is a genetic disease — that is, caused by changes in the genes that control how our cells work, especially how they grow and divide.
They can also happen in the life of a person as a result of errors that occur when dividing the cells or by the damage of the DNA caused by some exposures of the environment. The environmental exposures that cause cancer are substances, such as chemical compounds in tobacco smoke and radiation, such as ultraviolet rays of the sun. (Our Cancer prevention and causes page has more information.)
Even within each tumor, different cells may have different genetic changes.
In general, cancer cells have more genetic changes, such as mutations in the DNA, than normal cells. Some of these changes may not be related to cancer; can be the result of cancer and not its Caus
Malignant Mesotelioma pleural
The malignant mesotelioma is a neoplasia pleural related to the labor exhibition to asbestos, although other factors could be implied, with an incidence in increase in Western Europe. The thoracic pain and the shortness of breath are its most frequent clinical declarations. The image skills play an important role in the evaluation of the illness, being the TAC more extensively used, although the RM and the PET are postulated like skills that can contribute additional information in the diagnosis and prognosis of these patients. The survival is short and a consensus does not exist in the literature that guides the treatment of these patients due to the absence of information that support an increase of survival of no therapeutic form, although, recently the realized efforts have led to the development of new treatments that might change the current pessimistic vision of the illness on the part of medical and patient.
The diffuse mesotelioma is a slightly frequent malignant neoplasia that comes from the cells mesoteliales, being the pleura its most habitual location, they thinking that 10 % of the cases is located at level peritoneal1.
The mesotelioma is usually diagnosed in the fifth decade of the life with a clear predominance in the masculine, due sex the above mentioned to its relation with the labor exhibition to the asbestos. Its incidence is increasing in Europe, they waiting for a peak of the same one in the year 2018, affecting to the cohort of born males between 1945 and 19502, although, the incidence changes of considerable form in different geographical areas, reflecting the possibility of environmental and occupational exhibition to the asbestos. To emphasize also that the incidence increases in a linear way as regards the intensity of the exhibition, but in an exponential way with regard to the time passed from the first exhibition.
ETIOLOGY AND PATOGENIA
The exhibition to the asbestos is the main risk factor for the development of the mesotelioma. The first association between asbestos and cancer was established in 1955 in a study cases – control3, appearing in 1960 information that were relating it also to the mesotelioma pleural4. Since it has been exhibited in previous chapters, there exist two types of fibers of asbestos, the “curvilinear” (crisolita) and the “rectilinear” (crocidolita), being the above mentioned the principally involved ones in the tumor patogenia on having been transported towards the periphery of the lung and to contact the surface pleural, while the first ones remain in the central airlines and are eliminated by major facility. The latency period between the initial exhibition and the death changes extensively, being the average of 48 años5.
Numerous epidemiologic studies have demonstrated the relation between the exhibition to asbestos and the mesotelioma, as well as the development of the same one after the intrapleural instillation or inhalation of fibers of asbestos. Nevertheless, although 80 % of the patients has exhibition history to asbestos, only 10 % of the exposed ones develops mesotelioma6,7 what suggests the existence of other associate factors between which one emphasizes the role granted to the simian virus SV-40 as cofactor in the patogénesis of the mesotelioma after the expression of viral sequence is verified in models animales8. Some chromosomal abnormalities since delecciones of the regions 1q, 3p, 9p and 6q of the chromosome 22 have been quoted also in the patogenia of the mesotelioma.
Antman and col9 and Roviaro and col10 they have found relation between the existence of previous radiation and presence of calcification postuberculosa, respectively, with cases of mesotelioma. There is no definitive evidence of which the tobacco increases the risk of developing the illness.
Approximately two thirds of the patients who are diagnosed are in the status of age understood between the 40 and 70 years. In diverse series11,12, the shortness of breath and the thoracic pain are the two most frequent initial symptoms that lead to the suspicion of the illness, which appear in an insidious way, with several months of evolution up to being valued. The pain is usually of characteristics not pleuríticas and it can refer to the shoulder and top abdomen as a result of the diaphragmatic affectation.
As the illness progresses the general syndrome appears, with decrease of weight, anorexia, cough and febrícula.
The physical exploration reveals sometimes the loss of volume of the fond hemitórax as well as the effusion semiotics pleural with matidez in the percussion and decrease of the physiological murmur in to the sounding. Some patients are asymptomatic at the moment of the diagnosis and the initial presentation as illness is infrequent metastásica.
Radiology of conventional thorax
The most frequent radiological declaration is a unilateral engrosamiento pleural that it usually “wraps” to the lung associated with effusion pleural major than 50 % with decrease of volume of the fond lung and, as the illness progresses, a displacement takes place ipsilateral of the implied hemitórax
The TAC is superior to the radiography so much to determine the presence of the mesotelioma as to estimate its extension and invasion of mediastino, thoracic wall and top abdomen by what it must be realized in all the patients with suspicion of this tumoración. The main finds that suggest this neoplasia include the effusion pleural unilaterally, engrosamiento pleural nodular as well as of the cisura
Approximately in 20 % of the cases it is possible objetivar badges pleurales calcified. There takes place often loss of volume of the fond hemitórax with displacement ipsilateral of the mediastino and elevation of the hemidiafragma. With the local progression, there is not rare the invasion of the costal wall, although the aberration of the interface between wall and tumor is not predictiva of invasion. The mesotelioma can invade pericardium shown like aberration of the same one and presence of effusion, and vascular structures.
The pulmonary metástasis demonstrate like masses and nodules, acquiring rarely morphology miliar. In 40 % of the cases they exist metástasis ganglionares at the moment of the autopsy.
Although the TAC is used extensively in the evaluation of the mesotelioma, it is convenient to remember that images ganglionares of developing size do not imply necessary tumor invasion and that it can underestimate the affectation of the costal wall.
The use of 2 – [fluorín-18] fluoro-2-deoxy-D-glucosa (FDG) for the diagnosis of the mesotelioma has been recently descrito14, demonstrating reception levels more high places that the inflammatory pleuritis and the secondary engrosamiento to the exhibition to asbestos, helping to identify also metástasis extrathoracic, you conceal that exclude the patient for surgery. On the other hand, it might be useful to determine the place most adapted to realize the biopsy pleural that it takes us to the diagnosis, having been related the highest reception levels with worse pronóstico15.
The magnetic resonance can add additional information in the estadiaje of the mesotelioma, fundamentally, according to Heelan and col16, as for the diaphragmatic invasion and of the costal wall, being also useful in the patients allergic to the iodized contrast.
The diagnosis of mesotelioma malignant debit to be considered in all the patients with effusion pleural of not well-known etiology, being the grade of major suspicion in those of medium-sized age, with persistent thoracic pain and precedent of exhibition to asbestos.
In approximately half of the cases it is of appearance serosanguinolenta and it always fulfills exudado criteria, being the levels of glucose lower than 50 mg/dL and pH minor of 7,2 in a third of pacientes17 to distinguish cells mesoteliales you reactivate of neoplásicas and the mesotelioma of the adenocarcinoma metastático, therefore its sensibility is b
Biopsy pleural closed blind
It is realized in our way with Abrams’s needle and its profitability changes according to the series, being generally low, concerning 20 although in our own series (information without publishing) it is 80 %.
Biopsy pleural closed with TAC control
The profitability is major when the biopsy is realized by TAC control coming to 60 % with only one it takes and up to 85 % with biopsies repetidas21.
In some occasions it is necessary to come to more invasive procedures for the diagnosis a capture of biopsy must be realized well by means of toracoscopia, well by means of toracotomía, being in both cases the yield of the same ones of 90″, presenting the first one a less relative complications risk.
In general, the prognosis of the patients with mesotelioma is not good, with a survival average after the diagnosis from 8 to 12 meses23,24, and pretreatment depends in major measurement of the “factors” than of the effect of the realized therapeutic interventions. This way, The Cancer and Leukemia Group B25 has indicated like factors of bad prognosis the following ones: Major LDH of 500 IU/L in liquid pleural, under “performance status”, pain thoracic major, histology not epitelial, thrombocyte of 400.000/µL and age major of 75 year.
For his part, The European Organization for Research and Treatment of Cancer (EORTC) 24 has proposed the following ones: under “performance status”, leucocitosis, type sarcomatoso and masculine sex.
Consensus does not exist in the literature about the handling of the patients with mesotelioma pleural malignantly, owed largely to the absence of information that support the only form of treatment or combination of the same ones that offer a clear improvement in survival or quality of life on the treatment paliativo26
The paliación of the symptoms is the fundamental target of the treatment of the mesotelioma and it is necessary to center in those that previously we have mentioned like two fundamental symptoms: the shortness of breath and the thoracic pain. If the patient presents liquid pleural, it is necessary to realize a toracocentesis evacuadora and, if this relieves him, to value the achievement of pleurodesis chemistry.
Three surgical procedures have been used in the treatment of the mesotelioma: toracoscopia with pleurodesis, pleurectomía/decorticación and the neumonectomía extrapleural. As for the first one of them, a review reciente27 has concluded that the talc is the best agent esclerosante and the videotoracoscopia the best procedure to carry out it.
With regard to others two, a review sistemática28 has been very critical with the studies on which its use is based on having lacked group control and to base its best survival on the election before to the surgery of “favorable cases”. Realized with curative intention, none seems to offer a significant improvement of supervivencia29,30.
The mesotelioma pleural is a neoplasia with low answer to the chemotherapy. Berghmans and col31 they have realized a systematical review, being the on this side of the Rio de la Plata one the most active isolated agent and the combination with doxorrubicina the one that was contributing higher answer valuation. Pemetrexed is a new agent antifolato studied in phase III together with on this side of the Rio de la Plata versus cisplatino32 with favorable information as for the average survival for the combination and delay in the time of progression of the illness.
The mesotelioma answers to the radiotherapy, but given its extension at the moment of the diagnosis the treatment fields are wide, what makes its application difficult without important risks for the adjacent structures. Three possible utilities of the same one have signed up in the handling of the mesotelioma:
– As prophylaxis of “tumor sowing” after the achievement of biopsies or laying of drenajes33.
– As palliative treatment of the pain.
– As adjuvant to the neumonectomía extrapleural being part of a plan of multimodal treatment