Currently cancer has become a common disease which one person per three may suffer from it in their lifespan. Most common types of cancer are breast and uterus cancer in women and prostate and lung cancer in men. Even if the statistics are dreadful many of them can be prevented and cured by early diagnosis and preventive measures.
For this purpose it should be taken the preventive measures with regular cancer screening and in the worst scenario the tumor detecting in early stages should be eradicated before its progress.
Eventually cancer is a preventable and curable disease with early diagnosis. You need not to be afraid of cancer but to be late therefore you should find it before it finds you.
What is Cancer?
Cells which are the building blocks of the human body come together to compose the tissues; tissues come together to compose the organs. In this cycle cancer begins in cellular level but not in tissues or organs.
Normally, cells grow and divide to form new cells as the body needs them. When cells grow old, they die, and new cells take their place.
Sometimes, this orderly process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. These extra cells can form a mass of tissue called a growth or tumor. Tumors can be benign or malignant. Malignant tumors are cancer and they are life threatening.
Sometimes they can be extracted but they may relapse.
Cancer cells may spread and harm to adjacent tissues and organs. Spreading to the distant organs they may cause to occur new tumors.
What is oncology?
Oncology is the medical science dealing with tumors. The word oncology comes from the Latin words meaning "mass" or "bulk," referring to tumors and "logos" referring to science.
Which disciplines are dealing with Oncology?
Surgical oncology, medical oncology and radiation oncology are the medical disciplines involving in oncology. They treat and follow-up the patients closely by working in collaboration. Surgical oncology plays a role on diagnosis and extraction of the tumors. Many of surgical branches are included in this team (General Surgery, Ear Nose and Throat, Neurosurgery, Thoracic Surgery and orthopedics etc.). Following the diagnosis treatment is carried on with the cancer drugs and radiotherapy in cancer patients having the surgical treatment or in patients having inoperable tumor. Medical oncology (also pediatric oncology for children) is the medical branch giving the drug treatment to the cancer patients. Radiation oncology is the medical branch giving the radiation therapy to the cancer patients. As it is seen, cancer is a disease requiring multidisciplinary treatment.
What causes cancer?
Cancer develops after complex serial mechanisms. Currently it is accepted that cancer is a genetic disease. It means that it is not possible to develop cancer in a cell without any change in its genetic structure. Cancer develops after consecutive carcinogenic effects. Disturbance observed during the cancer development can be improved by various defense mechanisms. Immune system have active role in detecting and eliminating these disturbances. In spite of that cancer can develop. One of the main reasons is deficiency of defense mechanisms and immune system. In conclusion cancerous cells can increase and cause cancer disease.
Scientific studies have been demonstrated that following factors increase cancer risk.
-External factors (85%): Smoke, alcohol, chemical substances, radiation, particular infections, nutrition disorders, air pollution, sedentary life style and obesity
-Internal factors (15%): Inherent factors, mutations, immune deficiency, hormonal and metabolic disorders.
These factors may initiate cancer development acting synergistically or consecutively.
What does cancer risk mean?
Everybody may have cancer. However risk of cancer increase with age. 77% of all cancers occur in people ≥ 55 years old.
Cancer risk is defined in two ways:
1) Life-time risk: For example risk of breast cancer is 1/8 over the lifespan in a woman (i.e. one of the every eight women). Mortality rate is 1/35 (i.e. one of the every 35 women dies due to breast cancer). However despite these data it can be seen that breast cancer mortality is decreasing significantly. It is because of early diagnosis and improvement of the treatment methods.
2) Relative Risk: It defines relationship between cancer and one of the risk factors; i.e. risk differences between people exposed to the relevant risk factor and people not exposed.
For example risk of the lung cancer is 23 times higher in smokers than non-smokers.
Rate in the other factors are lower than this. For example risk of breast cancer in women having first degree relative with breast cancer is 2 times higher than others.
Although all cancers are related with dysfunction in genes controlling cell growth and replication, 5-10% of all cancers are hereditary.
Cancer Treatment Center
Since cancer treatment requires multidisciplinary approach cancer treatment should be conducted in centers specialized in cancer treatment.
Types of cancer?
Lung cancers have two types: Small cell and non-small cell lung cancer. Type of the cancer can be differentiated by microscopic examination. Both of them spread in different way and they have also different treatment.
Non small cell lung cancer
This is more common than small cell lung cancer. Non small cell lung cancer generally grows and spread slower than small cell cancer. There are three main types but there is no difference between them related to the treatment and survival.
Small cell lung cancer
It is called oat cell carcinoma. This is less common than non small cell cancer. Small cell cancer grows rapidly and it spreads to other organs more than non small cell cancer.
Risk factors for lung cancer
There is no only cause to grow lung cancer. Clinical trials have revealed several causes of lung cancer. Various factors may play role in development of lung cancer. Majority of them are related to smoking. Cancer is not a contagious disease. Some people have higher risk than the others. Cancer risks increase in following conditions.
Awareness of signs
Most common symptoms and signs of lung cancer;
-Ongoing and continuously worsening cough
-Stable chest pain
-Shortness of breath
-Pneumonia and bronchitis frequently
-Swelling in neck and face
-Appetite and weight loss
These signs may be caused by lung cancer and/or by less severe conditions. They should be evaluated by a doctor.
Diagnosis of lung cancer
Diagnosis of cancer can be made by evaluation of the biopsy tissue samples by pathologist via microscope.
If cancer is detected by investigations doctor will ask to know the disease stage. Aim of the staging is to know how and where the cancer spread.
In the digestive system, small intestine continues with the colon, also called the large intestine which is approximately 1.5-2 m. Last 15 cm of the colon is called rectum.
One in 50 people will have colorectal cancer in their lifespan.
Risk factors for colon cancer
Main risk factors for colon cancer are below:
-≥50 years old
-Family history of colon cancer
-Personal history of colon, breast, ovarian or uterus cancer
-Chronic inflammatory intestinal diseases such as ulcerative colitis or Crohn disease
-Frequent consumption of animal fat and red meat
-Diet that is poor in fiber
-High calorie intake and low physical activity
-Excessive smoking and alcohol consumption
Most common symptoms and signs of colon cancer
-Unexplained persistent diarrhea or constipation
-Blood in or on the stool
-Narrower stools than usual
-Unexplained weight loss
-Anemia and fatigue
Diagnosis of colon cancer
-Fecal occult blood test (this is a simple test; feces samples from patients are examined in laboratory).
-Radiologic investigations (Double-contrast barium enema, computerized tomography etc.)
-Laboratory investigations (Blood tests, biochemical tests). The CEA is an antigen which is raised in colon cancer so it is one of the diagnostic tests for colon cancer.
-Diagnosis of colorectal cancer can be confirmed by endoscopic examinations (rectoscopy, sigmoidoscopy, and colonoscopy) and biopsy (removal of a sample of tissue that is then examined under a microscope by pathologist).
For colon cancer prevention it is recommended to consume high-fiber food such as fruit and grain and also Ca and vitamin D. Besides these measures early detection with screening is also important as secondary prevention.
For this purpose everybody 50 or older should schedule a colon cancer screening as below;
-Annual fecal occult blood test; rectal examination and rectosigmoidoscopy in every 5 years or
-Rectal examination and complete colonoscopy in every 10 years or
-Double-contrast barium enema and rectal examination in every 5 -10 years
If there is a family history of colon cancer the screening program should be initiated at before 50 years old.
Most common sign of breast cancer is a lump or mass in the breast without pain. However 10% of the patients feel pain without mass. Less common signs of the breast cancer are permanent changes in breasts, redness, scaliness, or thickening of the nipple or breast skin, skin irritation or dimpling, a nipple discharge. Easily curable early stage of breast cancer typically gives no sign. Therefore it is so important to be followed the control programs. Early diagnosis in breast cancer increases the treatment opinions and chance of the treatment success and survival. For early diagnosis there are three complementary methods to be recommended.
-Breast self-examination by the woman
-Clinical breast examination by the doctor
As breast control program monthly breast examination after 20 years old and annual clinical breast examination and mammography after 40 years old are recommended. Also it should be have a reference mammogram before 40 years old. Risk level of breast cancer is determined by various factors such as family history, race, age of menarche, number of pregnancy.
Staging describes cancer stage, tumor size and spreading of cancer. Staging is rated from 0 to 4.
Stage 0 (Zero): It is also called "in-situ". In stage 0, there is no evidence of cancer cells or non-cancerous abnormal cells breaking out of the part of the breast in which they started, or of getting through to or invading neighboring normal tissue. There are two types based on cell origins such as milk glands or milk ducts.
Stage I: describes invasive breast cancer (cancer cells are breaking through to or invading neighboring normal tissue) in which the tumor measures up to 2 centimeters and no lymph nodes are involved.
Stage II: the tumor is larger than 2 centimeters but smaller than 5 centimeters and lymph nodes are involved or not.
Stage III A: Original tumor is found in auxiliary lymph nodes and cancer has spread out of the chest wall.
Stage III B: the tumor may be any size and has spread to the chest wall and chest lymph nodes.
Stage IV: the cancer has spread to other organs of the body -- usually the lungs, liver, bone, or brain.
What is ovarian cancer?
In healthy women ovaries have reproductive cells which are replicated in line with body need. In case of excessive replication of the abnormal cells are called "tumor". They may benign or malignant. For example benign ovarian cysts are small fluid-filled sacs that develop in women under 30 years old. They may disappear spontaneously or with operation. Benign tumors do not invade adjacent tissues. Contrarily malignant tumors invade both ovaries and adjacent tissues. Ovarian cancer may spread intestines, stomach and distant areas via blood and lymphatic circulation which is called "metastasis".
Most common types of the ovarian cancer are "epithelial ovarian cancer". While epithelial ovarian cancer incidence is 1/55 other types of them are seen very rare.
This is a curable cancer in case of early diagnosis. Unfortunately patients having early stage of the disease do not have any complain so that it is found as advanced stage at diagnosis. Therefore mortality of ovarian cancers is found higher than the other reproductive system cancers. In women ovarian cancer is the fourth cause of cancer mortality.
Signs of ovarian cancer
Many women are not diagnosed until the disease is advanced. Symptoms and signs such as bloating, abdominal/pelvic discomfort or pressure, loss of appetite or fullness, indigestion, nausea and weight loss may be seen.
Changes in bowel function or urinary frequency may occur because of the tumor pressure to the adjacent organs. Less commonly vaginal bleeding may be seen. Metastasis can give rise to ascites, a build-up of fluid in the abdomen that usually causes abdominal swelling and also a build-up of fluid in the lung membranes causes shortness of breath.
Diagnosis of ovarian cancer
After taking the history of disease pelvic and ultrasonographic examination is performed by a gynecologist. Additionally blood test of CA-125 which is the ovarian cancer marker is performed. But this marker may increase in benign ovarian tumors.
Diagnosis can be made only by examination of the biopsy from ovaries or fluid sample from abdominal fluid of the patients having ascites by "pathologist". The operation aiming to take biopsy from suspected tissues to make a diagnosis is called "laparotomy". Biopsy samples are examined by pathologist during the operation and in case of the pathologic examination is confirmed the cancer diagnosis operation will continue. The surgeon may extract uterus, tubes, ovaries and abdominal membrane and take samples from diaphragm, other organs, adjacent lymph nodes and abdominal fluid to complete the "surgical staging". All samples are examined by pathologist. It is so important to determine the extension of spreading for treatment and follow-up.
What is endometrial cancer?
Uterus cancer commonly develops from the internal layer of the uterus which is called endometrium. Uterus cancer caused by uncontrolled replication of the cells of endometrium. Cancer cells may reach to lymph nodes, adjacent organs or distant organs via blood circulation. Sarcoma is the less common cancer type of uterus cancer and they originate from muscular layer of the uterus.
Risk factors for endometrial cancer
Risk factors for endometrium cancer are obesity, hypertension (high blood pressure), diabetes mellitus, use of the unmet estrogen (not concomitantly progesterone), use of the breast cancer drugs, late menopause and nulliparity.
Signs of endometrial cancer
Most significant sign of the endometrial cancer is postmenopausal bleeding. In premenopausal women may be seen long term, excessive or irregular menstrual bleeding. In advanced disease abdominal swelling and constipation may occur.
In uterus cancer early diagnosis is possible with warning of vaginal bleeding. For early diagnosis annual gynecological examination should be done.
During the examination the patients having uterus cancer suspect, biopsy is performed by curettage. The curettage material is examined by pathologist to confirm cancer diagnosis.
Chemotherapy and Radiotherapy in Cancer Treatment
Chemotherapy means drug treatment. This is an important part of the treatment with surgery and radiotherapy. Chemotherapy kills the tumor cells or tries to prevent tumor growth. During the chemotherapy one or more drugs can be administrated in different ways. Some of them may be administrated orally but most of them are used by intravenously. Every drug has own mode of action and undesirable side effects.
Aim of the Chemotherapy
Causes of the chemotherapy vary depending on types of the tumor and patient characteristics.
-To destroy the tumor and to treat the patient
-To prevent tumor spreading
-To prevent or reduce tumor growing
-To dispel the signs of the tumor
While the tumor cannot be destroy completely and signs of the tumor may be improved for patient comfort even if it is not a so effective treatment.
What are Chemotherapy drugs?
During chemotherapy various drugs can be used. Many of them are chemotherapeutic drugs, hormones effective directly on tumor and biologic agents supporting immune system. Some of them are used for reducing or prevent undesirable effects of the drugs effective on tumors.