Etiology of Tumor

Etiology of tumors


Contents

  • Definition of the Tumor
  • Epidemiology of tumors
  • Disease category
  • Malignant Tumor Stages
  • Etiology
  • Basic cause
  • Symptoms
  • Systemic symptoms
  • Medical department
  • Diagnostic bases
  • Related checks
  • Pathological examination
  • Treatment/Therapy
  • Targeted therapy drugs
  • Surgical treatment
  • Chemotherapy
  • Radiation Therapy
  • Other treatments
  • Prognosis
  • Sequelae
  • Recovery
  • Relapse
  • Daily follow-up
  • Home care
  • Prevention

Overview of the topic

  • Abnormal growth of cells in the body to form lumps in parts of the body
  • There are mainly two types of malignant tumors and benign tumors
  • Pathological examination is the “gold standard” for tumor diagnosis.
  • Benign tumors have a good prognosis and are usually cured by surgical removal
  • The prognosis of malignant tumors is poor, and surgery combined with radiotherapy and chemotherapy is the main treatment.

Definition of the Tumor

  • Tumor is a kind of disease formed by the abnormal proliferation of cells in the body. The most prominent feature is the formation of tumors in local parts of the body.
  • Tumors can be divided into malignant tumors and benign tumors according to whether they are aggressive or not. Laboratory and imaging examinations are the important diagnostic basis, and pathological examination is the “gold standard” for diagnosis.
  • Surgical resection is an important means of tumor treatment. Benign tumors can generally be cured after resection, while malignant tumors must be combined with radiotherapy, chemotherapy, and biological therapy according to their conditions. Early detection and early treatment can improve the prognosis.

Epidemiology of tumors

  • Due to the improvement in medical and health conditions and people’s health awareness, the detection rate of tumors has gradually increased. Tumors can be found in people of all ages, and the incidence of cancer is directly proportional to age, and the incidence of cancer is higher for those over 40 years old.
  • Benign tumors generally do not endanger health, while malignant tumors are an important cause of human death. In 2020, about 9.6 million people will die of malignant tumors worldwide, the mortality rate of urban residents is 102.8/100,000, and the mortality rate of rural residents is 106.4/100,000. Malignant tumors with high mortality rates include lung cancer, gastric cancer, liver cancer, esophageal cancer, colorectal cancer, pancreatic cancer, breast cancer, brain tumor, leukemia, lymphoma, nasopharyngeal cancer, bladder cancer, and cervical cancer.

Contagious

Tumors are not contagious.

Disease category

Classification

Tumors can be divided into benign tumors and malignant tumors according to their aggressiveness.

  • Benign tumor: non-invasive or minimally invasive, does not spread to other parts, grows slowly, and causes little damage to the body. Benign tumors may also compress surrounding tissues or nerve vessels, causing obstruction or malnutrition in the body.
  • Malignant tumor: that is, “cancer”, which is highly invasive, highly disseminated, metastasized, proliferates, and is very harmful to health. Among them, malignant tumors derived from epithelial cells are called “carcinomas”, and malignant tumors derived from mesenchymal cells are called “sarcomas”.

Malignant Tumor Stages

Malignant tumor staging is an important indicator to guide treatment and judge prognosis, and the extent of the tumor (T), the extent of spread to the lymph nodes (N), and the presence of metastasis (M) (TNM) staging scheme are the most widely used.

  • T: represents the condition of the primary tumor, which can be represented by T1, T2, T3, and T4 according to its size and invasion level, and Tis refers to carcinoma in situ without invasion.
  • N: Represents lymph node involvement, N0 indicates no lymph node involvement, and N1, N2, and N3 indicate the number of patients with involvement.
  • M: Represents the spreading status; if there is no spreading or metastasis, it will be represented by M0; if it is metastatic, it will be represented by M1.

Etiology

The tumor is a genetic abnormality disease caused by multiple factors acting together for a long time. When the body is affected by the chemical, physical, virus, and other carcinogens in the environment, and/or due to the effects of its own genetics, endocrine, gender, age, and other factors, a series of abnormal genetic changes occur, forming a tumor.

Basic cause

Pathogenesis

The body is affected by various factors, resulting in abnormal gene changes, including activation of proto-oncogenes, inactivation of tumor suppressor genes, accumulation of various gene abnormalities, etc., and finally, forming a tumor.

Proto-oncogene activation

Under the action of environmental or genetic factors, the proto-oncogene changes its structure and transforms into an oncogene, transforming normal cells into tumor cells.

Tumor suppressor gene inactivation

Under normal circumstances, tumor suppressor genes have the function of inhibiting tumorigenesis. If the gene is inactivated, the inhibitory effect on tumors will be reduced or lost, and the cells will undergo malignant transformation to form tumors.

Accumulation of multiple genetic abnormalities

The abnormality of a single gene cannot completely transform the cell into a malignant one, and the activation of multiple proto-oncogenes and the inactivation of tumor suppressor genes accumulate, eventually leading to the occurrence of malignant tumors.

Pathogenic factors

It is mainly related to chemical substances, physical factors, viruses, and genetics.

Chemical material

  • Alkylating agents, acylating agents, nitrosamines, aromatic amines, epoxides, etc., have carcinogenic effects and cause abnormal gene mutations.
  • Croton oil, certain hormones, phenols, and other items will increase the effect of carcinogens.

Physical factors

Radiation (mainly ionizing radiation and ultraviolet light) is a clear carcinogen, while foreign body stimulation, trauma, chronic inflammation, etc., will promote the malignant process.

Virus

Some tumors are related to special virus infections, such as hepatitis virus, human papillomavirus (HPV), Epstein-Barr virus, etc., which are closely related to liver cancer, cervical cancer, and lymphoma, respectively.

Heredity

Some tumors are hereditary in families, such as familial multiple adenomatous polyposis of the colon and neurofibromatosis.

Predisposing factors

Bad habits such as smoking, drinking, and staying up late, as well as physiological factors such as gender, aging, and obesity, are also risk factors for certain tumors.

Symptoms

The clinical manifestations of tumor patients are related to factors such as the tumor’s nature, location, and growth rate. There are usually no obvious symptoms in the early stage of the lesion. As the tumor grows, local symptoms such as lumps, pain, bleeding, and obstruction appear, as well as systemic symptoms such as fever, fatigue, anemia, and emaciation.

Typical symptoms

Local symptoms

Lump

It is often the first symptom of superficial tumors, and finding those with deep tumors is difficult. Benign tumors grow slowly and have little change in volume over a long period of time. Malignant tumors grow quickly and easily metastasize. One or more huge masses may appear in a short period of time.

Pain

Tumor growth, metastasis, etc., will destroy and invade local tissues or nerves, and various types and degrees of pain will appear, especially at night.

Bleeding

Rapid tumor growth can cause rupture and bleeding, such as lung cancer with blood in sputum and hemoptysis, gastrointestinal cancer with hematemesis, melena, and bloody stool, kidney cancer and bladder cancer with hematuria, and gynecological tumors with hematuria. Vaginal bleeding etc.

Obstruction

It is related to tumor blockage, such as vomiting and difficulty in defecation caused by obstruction of gastrointestinal cancer, and jaundice caused by restricted bile discharge in cancer of the head of the pancreas.

Systemic symptoms

Fever

A low-grade fever is more common and usually does not require treatment. Typical lymphoma patients may have a fever, night sweats, and weight loss symptoms.

Weakness

Tumor cells secrete abnormal cytokines, and patients may have fatigue, many of which are not specific.

Anemia

The consumption of the body by the tumor, the rupture of the tumor body, and other reasons cause anemia in the patient, which needs to be treated in time.

Weight loss

Due to the energy consumption of the tumor body, insufficient nutritional intake, and concurrent infection, the patient’s weight continues to drop, and patients with advanced malignant tumors can be extremely emaciated.

Seek medical attention

Those with a family history of cancer and tumor-related diseases should be admitted to the hospital for regular check-ups to find early-stage lesions; When you have symptoms such as dyspnea, you should be admitted to the hospital for emergency treatment to avoid life-threatening.

Medical department

The first visit to the department is related to the symptoms of the onset. Those who are diagnosed with tumors can go to the oncology department, surgery department, radiotherapy department, etc., according to the purpose.

Diagnostic bases

Patients with abnormal clinical symptoms should consider the possibility of tumors, especially those with local masses, which can be combined with laboratory and imaging examinations for auxiliary diagnosis. Finally, it is necessary to rely on pathological examination to determine whether it is a tumor, the nature, and the type of the tumor.

Physical examination

Doctor’s checkup

  • Observe whether there is a local mass in the patient, and clarify its location, boundary, texture, color, pain, activity, etc.
  • Inquire about the patient’s onset, course of the disease, family history, past medical history, living environment, personal habits, and other information.

Related checks

Lab test

Blood routine

If the red blood cells and hemoglobin decrease, it indicates anemia, which needs to be corrected in time; if the white blood cells increase significantly, it indicates that the patient is concurrently infected; if there are a large number of immature white blood cells in the blood, it indicates that there may be leukemia.

Stool routine

If there is blood in the stool or bloody stool, it may indicate that there may be a tumor in the digestive tract.

Liver and kidney function

Tumors of the digestive system, such as the gallbladder, pancreas, liver, and gastrointestinal tract, are often accompanied by abnormal liver function; abnormal renal function often occurs in tumors of the kidney, bladder, ureter, and urinary tract.

Specific blood test items

The examination of tumor markers is of great significance for the screening and follow-up review of patients with malignant tumors. The commonly used indicators include alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), cancer antigens (CA125, CA153, CA50, etc.), prostate-specific antigen (PSA, etc.), squamous cell carcinoma antigen (SCCA), calcitonin (CT), human chorionic gonadotropin (HCG), etc.

Imaging Tumor Examination

X-ray, ultrasound, radionuclide imaging, CT, MRI, and other techniques can all be used for tumor examination. Different patients can choose the appropriate examination method according to their own conditions, such as X-ray mammography examination of breast tumors, ultrasound examination of gynecological tumors, CT examination of liver, gallbladder, and lung tumors, MRI examination of brain tumors, and nuclear imaging PET examination for malignant tumor metastasis.

Pathological examination

Cytology

Such as pleural and peritoneal effusion, sputum, urine, cervical exfoliated cell examination, etc., can find abnormal tumor cells.

Histological examination

Lesioned tissue obtained through the puncture, biopsy, or radical surgery, combined with Immunohistochemical staining, special staining, molecular pathological testing, etc., can clarify the nature, type, stage, etc. of the tumor to guide the next step of clinical treatment.

Treatment/Therapy

Surgical resection is an effective means of treating tumors. Complete resection is enough for benign tumors. Surgical treatment should be sought for malignant tumors as much as possible. Those who need it can combine radiotherapy, chemotherapy, targeted therapy, biological therapy, and other methods.

Acute treatment

Many tumors develop emergent conditions during their development that require urgent management.

  • Bleeding: such as nasopharyngeal cancer, lung cancer, liver cancer, etc., need to stop bleeding in time.
  • Compression: If the trachea is compressed by esophageal cancer or thyroid tumor, timely tracheotomy is required; if the brain metastases or the brain tumor compresses the central nervous system, intracranial decompression should be performed in time.
  • Perforation: Gastrointestinal malignant tumors are more common and are caused by the tumor destroying the digestive tract wall. Repair or local tumor resection should be carried out as soon as possible.

General treatment

  • Emergency admissions should monitor their heart rate, blood oxygen saturation, and other indicators and pay attention to their state of consciousness and respiratory rate.
  • Timely infusion, replenishing water and nutrition, avoiding water and electrolyte disorders, and malnutrition, especially those who eat poorly due to tumors.

Medical treatment

Due to large individual differences, there is no absolute best, fastest, or most effective medication. Except for commonly used over-the-counter drugs, you should choose the most appropriate drug based on your personal situation under the guidance of a doctor.

Symptomatic drugs

Anti-inflammatory drugs can be used if accompanied by local infection and pain; antiviral drugs can be used for those related to viral infection.

Targeted therapy drugs

For the treatment of malignant tumors only, there are many types. Common drugs include rituximab, trastuzumab, bevacizumab, tipifarnib, imatinib, sorafenib, sunitinib, angiostatin, bortezomib, etc.

Advantage

It is more targeted to the tumor, with high efficiency, remarkable curative effect, and fewer adverse reactions.

Shortcoming

It only applies to tumor patients with a certain type of target, which has limitations; the cost of treatment is high; drug resistance may also occur; it is difficult to achieve a cure only for individual targets.

Surgical treatment

Surgical principles

Benign tumor

For complete resection of the tumor, in addition to dissection or partial resection of the brain tumor, a small amount of normal tissue around the tumor should be resected as much as possible. The pathological examination must be performed to clarify the nature of the resected tumor. If it is a borderline tumor or accompanied by malignant transformation, we need to expand the scope of resection.

Malignant tumor

Before the operation, the level and extent of tumor invasion should be comprehensively evaluated to determine the surgical method and the scope of resection. The tumor should be completely resected as much as possible to reduce the possibility of tumor metastasis. Guide postoperative treatment.

Surgical Indications

Surgery is mainly used for the treatment of tumors and is also applicable to the prevention, diagnosis, staging, postoperative structural reconstruction, and functional rehabilitation of tumors.

Surgery

Preventive surgery

It is used for patients who may develop malignant tumors, such as cryptorchidism, familial polyposis of the colon, breast dysplasia, and oral leukoplakia.

Diagnostic surgery

Specimens can be obtained by fine-needle aspiration, puncture or excisional biopsy, and sentinel lymph node biopsy to clarify the tumor’s nature, type, and stage.

Curative surgery

  • Radical surgery: the tumor is limited or only involves regional lymph nodes and adjacent tissues without distant metastasis, and surgery can remove them together. This operation does not guarantee a cure; some patients will relapse or metastasize.
  • Palliative surgery: It is impossible to remove the primary tumor or metastases, or because the patient’s acute symptoms are severe, surgery must be performed first, and then radical surgery should be sought.
  • Metastasis resection: On the basis of good control of the primary tumor, resection of liver, lung, and brain metastases is common in clinical practice.
  • Endocrine gland resection for hormone-dependent tumors: For breast cancer, the ovary and pituitary gland can be removed, and for prostate cancer, the testis is removed, which is now rarely used.
  • Structural reconstruction and functional rehabilitation: On the basis of ensuring the therapeutic effect, to improve the quality of life of patients, such as structural reconstruction after breast cancer surgery, voice reconstruction surgery for laryngeal cancer, etc.

Advantages and disadvantages

Advantage

No biological resistance; no potential carcinogenic risk; not affected by tumor differences; can provide an accurate pathological stage and histological type; suitable for most non-metastatic tumors.

Shortcoming

It will destroy normal tissues; there may be surgical complications, which can cause deformities, affect normal functions, and even endanger life; patients with metastases cannot be completely cured; vital organs cannot be completely removed.

Chemotherapy

Treatment mode

Including neoadjuvant chemotherapy, perioperative chemotherapy, adjuvant chemotherapy, radical chemotherapy, induction chemotherapy, consolidation chemotherapy, palliative chemotherapy, maintenance chemotherapy, conversion chemotherapy, low-dose metronomic chemotherapy, etc.

Efficacy classification and indications

Radical chemotherapy

Chemotherapy may be cured, or curative effect is better, suitable for choriocarcinoma, leukemia, lymphoma, multiple myeloma, embryonal rhabdomyosarcoma, testicular cancer, Ewing sarcoma, neuroblastoma, small cell lung cancer, etc.

Adjuvant chemotherapy

Together with other methods, it can delay the progression of lesions and improve symptoms. It has definite curative effects on anal canal cancer, ovarian cancer, breast cancer, bladder cancer, laryngeal cancer, osteosarcoma, rectal cancer, gastric cancer, and basal cell carcinoma. Small cell lung cancer, nasopharyngeal cancer, malignant mesothelioma, endometrial cancer, pancreatic cancer, prostate cancer, etc., may be of value.

Adverse reactions

Different chemotherapy drugs have different side effects; the more common ones include the following.

  • Digestive system toxicity: mainly oral mucositis, nausea, vomiting, diarrhea, and other symptoms.
  • Bone marrow suppression: reduction of red blood cells, white blood cells, and platelets, and patients have related symptoms such as anemia, infection, and easy bleeding.
  • Pulmonary toxicity: patients may have a cough, dyspnea, fever, and other symptoms.
  • Cardiotoxicity: Patients may have an arrhythmia, acute chest pain, and other symptoms.
  • Neurotoxicity: central nervous system injury may cause symptoms such as hemiplegia, aphasia, and dementia, and peripheral nerve injury may cause extremity paresthesia, muscle weakness, and muscle atrophy.
  • Skin toxicity: patients have symptoms such as hair loss, rash, pigmentation, and paronychia.
  • Liver and kidney toxicity: The patient has abnormally elevated serum urea nitrogen, creatinine, transaminase, bilirubin, and other indicators.

Radiation Therapy

Treatment methods and indications

Definitive radiotherapy

Radiation therapy is used as the main means to kill tumor cells and achieve the purpose of cure. It is suitable for nasopharyngeal cancer, head and neck cancer, prostate cancer, cervical cancer, anal canal cancer, lung cancer, esophageal cancer, malignant lymphoma, skin squamous cell carcinoma, giant cell tumor of bone, etc.

Palliative radiotherapy

It is used to relieve symptoms and delay the progression of lesions. It is suitable for patients with advanced stage or metastases in the brain, spinal cord, bone, and other parts.

Combination therapy

It is used as adjuvant therapy before, during, and after surgery, combined with chemotherapy, etc. It is suitable for local treatment of advanced rectal, cervical, breast, laryngeal, and other tumors.

Adverse reactions

Early adverse reactions

It occurs during treatment or within 1 to 3 months of treatment, including fatigue, nausea, anorexia, skin itching and swelling, oropharyngeal pain, and local hair loss. Most of the symptoms are temporary, and they can recover independently after stopping treatment.

Late adverse reactions

Occurs months or years after treatment, with dry mouth, thickened skin, and subcutaneous tissue, nerve damage, abnormal cardiopulmonary function (such as dry cough, wheezing, etc.), gastrointestinal dysfunction (such as nausea, vomiting, weight loss, etc.) And other manifestations, the symptoms are more serious and long-lasting and should be avoided as much as possible.

Other treatments

Biological therapy: At present, immune checkpoint inhibitor therapy (PD-1 and PD-L1) and chimeric antigen receptor T cell immunotherapy (CART) have achieved initial clinical results for advanced patients, but most biological therapies are not yet mature enough. Some are still in the research stage.

  • Principle: It can control and kill tumors by stimulating and enhancing the body’s immune function.
  • Main technologies: cellular vaccines, molecular vaccines, anti-tumor antibodies, adoptive immunotherapy, cytokine therapy, etc.

Prognosis

Most benign tumors have a good prognosis and are not life-threatening. Patients with early-stage malignant tumors may be cured after timely and effective treatment, while patients with advanced stages are more difficult to cure and may relapse or metastasize, but active treatment can delay the progression of the disease and improve the quality of life.

Sequelae

Tumors in some special parts will destroy the structure’s original function. For example, cranial nerve tumors may cause hemiplegia, dementia, aphasia, etc.; tumors that occur in the bones and muscles of the limbs may cause disability and muscle atrophy.

Recovery

Some cancer patients need rehabilitation treatment. As bone tumors, soft tissue tumors of limbs, etc., will affect the normal activities of the limbs, it is necessary to do targeted muscle and nerve function training to promote functional recovery. , Vocal practice, improve the quality of life.

Relapse

Benign tumors basically do not recur or metastasize after complete resection. Malignant tumors are prone to recurrence and metastasis. The recurrence and metastasis rates of early-stage patients are relatively low, while the recurrence and metastasis rates of advanced patients are high, and the prognosis is poor.

Daily follow-up

Tumor patients should actively cooperate with the treatment, especially those with malignant tumors; they should follow the doctor’s daily medication, healthy diet, moderate exercise, etc., in order to improve the curative effect and prognosis.

It is worth noting that patients must be regularly reviewed to detect metastasis or recurrence as early as possible and treat them in time.

Home care

Patient

  • Quit smoking and drinking as soon as possible, and avoid exposure to smoke, exhaust, chemicals, harmful rays, etc.
  • Master the precautions for taking medicine, follow the doctor’s advice, and do not increase or decrease the dosage or stop the medicine at will.
  • Regular follow-up visits, such as severe pain, bleeding, difficulty breathing, etc., seek medical treatment in time.

Family members

  • Pay attention to the patient’s emotions, communicate with the patient more, and encourage him to accept treatment actively.
  • Keep the living environment fresh air and more ventilation.
  • Quit smoking or do not smoke, and reduce passive smoking in patients.
  • Pay attention to observe the patient’s body temperature, breathing, and other conditions, and assist bedridden patients in turning over.

Daily life management

  • Take more rest and exercise appropriately, such as slow walking, etc., to improve the body’s resistance.
  • Adjust eating habits, eat fruits and vegetables and high-protein foods such as lean meat, fish, and eggs, with less oil and salt, and avoid spicy food, smoked, grilled, and pickled foods.
  • Regular work and rest, change personal bad habits, quit smoking and drinking.
  • Adjust your mentality and relieve mental stress through communication, discussions and relative healthy activities etc.

Special considerations

  • Regular reexamination is required after tumor treatment, especially for patients with malignant tendencies and malignant tumors, in order to monitor the curative effect and early detection of tumor recurrence and metastasis.
  • The reexamination is mainly based on imaging examination, and the general reexamination cycle is: within 2 years after treatment, reexamination once every 3 months; within 2 years to 5 years, reexamination once every six months; after 5 years, reexamination once a year. The specific review cycle should follow the doctor’s advice.
  • Detecting tumor markers is meaningful for the follow-up of patients with malignant tumors. It is recommended that patients should be tested for tumor markers every 3 months within 1 to 3 years after the start of treatment, every six months within 3 to 5 years, and once a year after 5 years. If the tumor markers are found to be significantly increased (over 25%) during the follow-up, retesting should be done within one month. If the tumor markers are still elevated, it may indicate the possibility of recurrence or metastasis.

Prevention

At present, there is no effective way to prevent tumors, but the probability of tumor occurrence can be reduced through the following ways.

  • Avoid carcinogens at work, such as taking precautions to prevent exposure to toxic chemicals, reduce radiation exposure, etc.
  • Quit bad habits, do not smoke, and drink.
  • Increase the number of vegetables, fruits, grains, etc., in the diet, and do not eat greasy, pickled, smoked, and roasted foods.
  • Go to bed early and get up early to ensure rest and avoid endocrine disorders.
  • Pay attention to rest and exercise properly in life.
  • Timely treatment of inflammation, viral infection, and other diseases, avoiding foreign body stimulation, and regular physical examination.

References

Patel A. Benign vs Malignant Tumors. JAMA Oncol. 2020;6(9):1488. doi:10.1001/jamaoncol.2020.2592

Neal, R D et al. “Is increased time to diagnosis and treatment in symptomatic cancer associated with poorer outcomes? Systematic review.” British journal of cancer vol. 112 Suppl 1,Suppl 1 S92-107. 31 Mar. 2015, doi:10.1038/bjc.2015.48

Shibata, H., et al. (2016). “Diagnosis and treatment of bone metastasis: comprehensive guideline of the Japanese Society of Medical Oncology, Japanese Orthopedic Association, Japanese Urological Association, and Japanese Society for Radiation Oncology.” ESMO Open 1(2): e000037.


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Dr AF Saeed

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