NEUROBLASTOMA
Neuroblastoma is an embryonal tumor of the peripheral sympathetic nervous system. It is the third most common type of cancer in children. It constitutes 8% of all childhood tumors. It is the most frequently diagnosed tumor in infants under one year of age. 90% of the patients are diagnosed before the age of five. Its incidence is higher in boys and Caucasians. It can develop from the adrenal medulla. It is highly malignant and the degree of malignancy can be unpredictable, its texture can vary from malignant to benign
tumor appearance. There are also publications showing that it can regress spontaneously.
It is generally the disease of the 0-10 age group. It is most common between the ages of 18 months and 2 years. 90% of the patients are diagnosed by the age of 7-8 years.
It is the most common intra-abdominal malignant tumor in the newborn. These tumors are similar to other small cell tumors such as rhabdomyosacoma, Ewing sarcoma and non-Hodgkin lymphomas.
Prognosis depends on the definition of tissue structure. Prognosis; The amount of connective tissue in the tumor determines the degree of differentiation of tumor cells and the number of mitosis (proliferation) in tumor cells.
The genetic defect that initiates neuroblastoma is unknown.
The tumor is mostly located in the posterior intra-abdominal wall (75%). About 50% of this is in the medulla of the adrenal gland and 25% of it develops from the spinal ganglia emerging from the spinal cord. occurs in the pelvic cavity.
Symptoms and Findings:
Patients may apply to the physician with various complaints depending on the location of the tumor, its spread and sometimes the symptoms caused by the hormone they secrete. The vast majority of patients apply to the physician with the complaint of a mass in the abdomen.
Abdominal pain, weight loss, swelling in the abdomen, fever and anemia may accompany the picture. High blood pressure due to hormones secreted from the tumor is observed in 25% of the cases. Calcification due to bleeding in the tumoral mass is seen in the direct abdominal X-ray.
Tumors in the posterior and upper thoracic cavity or neck show signs of Horner’s Syndrome (droopy eyelid, bleeding in the eye).
In tumors seen in the posterior chest wall, findings such as respiratory distress and difficulty in swallowing can be seen.
Neuroblastomas can spread directly to the surrounding tissues. It can spread to near and far areas via lymph and blood. Tumor; It can involve the lymph nodes, liver, bone marrow and cortex of the bone. Bone metastases, in order of frequency, are long and flat bones (skull bones, spine, pelvis, ribs, and fibula). Bleeding due to thrombocyte reduction and disruption of coagulation factors may be seen in diffuse bone marrow involvement.
Diagnosis
Abdominal radiography, computed tomography (CT) and ultrasonography easily lead the physician to diagnosis and to find out how far the tumor has spread.
The level of adrenaline, noradrenaline, DOPA in the blood and VMA in the 24-hour urine should be determined.
Although neuroblastoma-specific rosette formation may be seen in bone marrow biopsies, the definitive diagnosis can be made by microscopic examination of a piece of tumor tissue.
Treatment
Treatment and outcomes of neuroblastoma are related to the extent of the tumor at the time of diagnosis.
During the diagnosis, the clinical stage of the tumor is determined according to some criteria. Evans’ staging is the most commonly used one of the various staging methods.
Evans Staging:
Stage 1: The tumor is only in one organ or structure. It can be completely removed surgically.
STAGE 2: The tumor has extended beyond the organ of origin, but has not crossed the midline of the body. Adjacent lymph nodes may be involved. The tumor can be removed along with the adjacent lymph nodes.
Stage 3: The tumor is large, usually crossing the midline. Often it cannot be completely removed. Tumor tissue remains. The lymph nodes on the opposite side may be involved with tumor.
Stage 4: There is distant spread. Bone, surrounding tissues, other organs and distant lymph nodes may be involved.
4-S STAGE: Indicates distantly disseminated disease in children younger than one year old. There are liver, skin, bone marrow spreads. The cortex (hard part) of the bone is not involved.
Treatment:
It is planned according to the stage of the tumor.
In STAGE-1, the tumor should be completely removed. Since neuroblastoma is surrounded by an easily damaged false capsule, meticulous attention should be paid during the surgical intervention to prevent the tumor tissue from spreading around.
While the majority of the masses in the STAGE-2 stage can be completely removed, some of them can be left behind. In these patients, treatment should be continued with chemotherapy. While good results were obtained with chemotherapy in many malignant tumors, the desired result could not be achieved in neuroblastomas. While 40% of patients with metastases respond completely to chemotherapy, 30% do not respond at all.
If the tumor regresses as a result of drug treatment in STAGE-2, it would be appropriate to surgically remove the remainder. In the meantime, the success of the treatment is evaluated by taking samples from the surrounding lymph nodes.
STAGE-3 In addition to surgical intervention, chemotherapy and radiotherapy are required in neuroblastomas.
Intensive chemotherapy should be given in STAGE-4 tumors. After effective chemotherapy, the shrinking tumoral mass should be removed. If necessary, radiotherapy can be applied to the tumor bed.
In cases with STAGE 4-S, efforts should be made to remove the main tumoral focus, even if there is extensive liver spread. The more the tumoral mass is removed, the greater the effect of chemotherapy and radiotherapy will be. Since there is a possibility of conversion to STAGE 4 in STAGE 4 S cases with bone marrow involvement, chemotherapy is appropriate.
Results: In children younger than one year old with neurolastoma, the prognosis of the disease is markedly good in Stage 1, 2, 4-S tumors, and worse in Stages 3 and 4 in older children.
It is important in the region of origin of the tumor. Cervical, mediastinal, and pelvic neuroblastomas have a better clinical course than retroperitoneal, paraspinal, or adrenal localized neuroblastomas.
Histopathologically mature patients have a better prognosis. The survival rate is over 90%.
In high-risk neuroblastoma cases that do not respond well to chemotherapy and radiotherapy; Good results are generally reported with induction chemotherapy followed by high-dose chemotherapy and autologous bone marrow or stem cell transplantation.
Despite many developments, neuroblastoma continues to be a difficult tumor to be eradicated. On the other hand, it is hoped that biological studies on Neuroblastoma will also identify new genetic targets for treatment.
childhood tumors
