Monday 28 November 2016

What is testicular cancer ??

Cancer starts when cells in the body begin to grow out of control. Cells in nearly any part of the body can become cancer, and can spread to other areas of the body. To learn more about how cancers start and spread, see What Is Cancer ?

Cancer that starts in the testicles is called testicular cancer. To understand this cancer, it helps to know about the normal structure and function of the testicles.

Testicles (also called the testes; a single testicle is called a testis) are part of the male reproductive system. These 2 organs are each normally a little smaller than a golf ball in adult males and are contained within a sac of skin called the scrotum. The scrotum hangs beneath the base of the penis.


Testicles have 2 main functions:
  • They make male hormones (androgens) such as testosterone.
  • They make sperm, the male cells needed to fertilize a female egg cell to start a pregnancy.
Sperm cells are made in long, thread-like tubes inside the testicles called seminiferous tubules. They are then stored in a small coiled tube behind each testicle called the epididymis, where they mature.

During ejaculation, sperm cells are carried from the epididymis through the vas deferens to seminal vesicles, where they mix with fluids made by the vesicles, prostate gland, and other glands to form semen. This fluid then enters the urethra, the tube in the center of the penis through which both urine and semen leave the body.

The testicles are made up of several types of cells, each of which can develop into one or more types of cancer. It is important to distinguish these types of cancers from one another because they differ in how they are treated and in their prognosis (outlook).

Germ cell tumors

More than 90% of cancers of the testicle develop in special cells known as germ cells. These are the cells that make sperm. The 2 main types of germ cell tumors (GCTs) in men are:
  • Seminomas
  • Non-seminomas, which are made up of embryonal carcinoma, yolk sac carcinoma, choriocarcinoma, and/or teratoma
Doctors can tell what type of testicular cancer you have by looking at the cells under a microscope.

These 2 types occur about equally. Many testicular cancers contain both seminoma and non-seminoma cells. These mixed germ cell tumors are treated as non-seminomas because they grow and spread like non-seminomas.

Seminomas

Seminomas tend to grow and spread more slowly than non-seminomas. The 2 main subtypes of these tumors are classical (or typical) seminomas and spermatocytic seminomas. Doctors can tell them apart by how they look under the microscope.

Classical seminoma: More than 95% of seminomas are classical. These usually occur in men between 25 and 45.

Spermatocytic seminoma: This rare type of seminoma tends to occur in older men. The average age of men diagnosed with spermatocytic seminoma is about 65. Spermatocytic tumors tend to grow more slowly and are less likely to spread to other parts of the body than classical seminomas.

Some seminomas can increase blood levels of a protein called human chorionic gonadotropin (HCG). HCG can be detected by a simple blood test and is considered a tumor marker for certain types of testicular cancer. It can be used for diagnosis and to check how the patient is responding to treatment.

Non-seminomas

These types of germ cell tumors usually occur in men between their late teens and early 30s. The 4 main types of non-seminoma tumors are:
  • Embryonal carcinoma
  • Yolk sac carcinoma
  • Choriocarcinoma
  • Teratoma
Most tumors are a mix of different types (sometimes with a seminoma component as well), but this doesn’t change the general approach to treatment of most non-seminoma cancers.

Embryonal carcinoma : This type of non-seminoma is present to some degree in about 40% of testicular tumors, but pure embryonal carcinomas occur only 3% to 4% of the time. When seen under a microscope, these tumors can look like tissues of very early embryos. This type of non-seminoma tends to grow rapidly and spread outside the testicle.

Embryonal carcinoma can increase blood levels of a tumor marker protein called alpha-fetoprotein (AFP), as well as human chorionic gonadotropin (HCG).

Yolk sac carcinoma : These tumors are so named because their cells look like the yolk sac of an early human embryo. Other names for this cancer include yolk sac tumor, endodermal sinus tumor, infantile embryonal carcinoma, or orchidoblastoma.

This is the most common form of testicular cancer in children (especially in infants), but pure yolk sac carcinomas (tumors that do not have other types of non-seminoma cells) are rare in adults. When they occur in children, these tumors usually are treated successfully. But they are of more concern when they occur in adults, especially if they are pure. Yolk sac carcinomas respond very well to chemotherapy, even if they have spread.

This type of tumor almost always increases blood levels of AFP (alpha-fetoprotein).

Choriocarcinoma:
 This is a very rare and aggressive type of testicular cancer in adults. Pure choriocarcinoma is likely to spread rapidly to distant organs of the body, including the lungs, bones, and brain. More often, choriocarcinoma cells are present with other types of non-seminoma cells in a mixed germ cell tumor. These mixed tumors tend to have a somewhat better outlook than pure choriocarcinomas, although the presence of choriocarcinoma is always a worrisome finding.

This type of tumor increases blood levels of HCG (human chorionic gonadotropin).

Teratoma: Teratomas are germ cell tumors with areas that, under a microscope, look like each of the 3 layers of a developing embryo: the endoderm (innermost layer), mesoderm (middle layer), and ectoderm (outer layer).

Pure teratomas of the testicles are rare and do not increase AFP (alpha-fetoprotein) or HCG (human chorionic gonadotropin) levels. More often, teratomas are seen as parts of mixed germ cell tumors.

There are 3 main types of teratomas:
  • Mature teratomas are tumors formed by cells similar to cells of adult tissues. They rarely spread to nearby tissues and distant parts of the body. They can usually be cured with surgery, but some come back (recur) after treatment.
  • Immature teratomas are less well-developed cancers with cells that look like those of an early embryo. This type is more likely than a mature teratoma to grow into (invade) surrounding tissues, to spread (metastasize) outside the testicle, and to come back (recur) years after treatment.
  • Teratomas with somatic type malignancy are very rare cancers. These cancers have some areas that look like mature teratomas but have other areas where the cells have become a type of cancer that normally develops outside the testicle (such as a sarcoma, adenocarcinoma, or even leukemia).
Carcinoma in situ of the testicle

Testicular germ cell cancers can begin as a non-invasive form of the disease called carcinoma in situ (CIS) or intratubular germ cell neoplasia. In testicular CIS, the cells look abnormal under the microscope, but they have not yet spread outside the walls of the seminiferous tubules (where sperm cells are formed). Carcinoma in situ doesn’t always progress to invasive cancer.

It is hard to find CIS before it does become an invasive cancer because it generally does not cause symptoms and often does not form a lump that you or the doctor can feel. The only way to diagnose testicular CIS is to have a biopsy (a procedure that removes a tissue sample and looks at it under a microscope). Some cases are found incidentally (by accident) when a testicular biopsy is done for another reason, such as infertility.

Experts don’t agree about the best treatment for CIS. Since CIS doesn’t always become an invasive cancer, many doctors in the United States consider observation (watchful waiting) to be the best treatment option.

When CIS of the testicle becomes invasive, its cells are no longer just in the seminiferous tubules but have grown into other structures of the testicle. These cancer cells can then spread either to the lymph nodes (small, bean-shaped collections of white blood cells) through lymphatic channels (fluid-filled vessels that connect the lymph nodes), or through the blood to other parts of the body.

Stromal tumors

Tumors can also develop in the supportive and hormone-producing tissues, or stroma, of the testicles. These tumors are known as gonadal stromal tumors. They make up less than 5% of adult testicular tumors but up to 20% of childhood testicular tumors. The 2 main types are Leydig cell tumors and Sertoli cell tumors.

Leydig cell tumors

These tumors develop from the Leydig cells in the testicle that normally make male sex hormones (androgens like testosterone). Leydig cell tumors can develop in both adults and children. These tumors often make androgens (male hormones) but sometimes produce estrogens (female sex hormones).

Most Leydig cell tumors are benign. They usually do not spread beyond the testicle and are cured with surgery. But a small portion of Leydig cell tumors spread to other parts of the body and tend to have a poor outlook because they usually do not respond well to chemotherapy or radiation therapy.

Sertoli cell tumors

These tumors develop from normal Sertoli cells, which support and nourish the sperm-making germ cells. Like the Leydig cell tumors, these tumors are usually benign. But if they spread, they usually don’t respond well to chemotherapy and radiation therapy.

Secondary testicular cancers


Cancers that start in another organ and then spread to the testicle are called secondary testicular cancers. These are not true testicular cancers – they are named and treated based on where they started.

Lymphoma is the most common secondary testicular cancer. Testicular lymphoma occurs more often than primary testicular tumors in men older than 50. The outlook depends on the type and stage of lymphoma. The usual treatment is surgical removal, followed by radiation and/or chemotherapy.

In boys with acute leukemia, the leukemia cells can sometimes form a tumor in the testicle. Along with chemotherapy to treat the leukemia, this might require treatment with radiation or surgery to remove the testicle.

Cancers of the prostate, lung, skin (melanoma), kidney, and other organs also can spread to the testicles. The prognosis for these cancers tends to be poor because these cancers have usually spread widely to other organs as well. Treatment depends on the specific type of cancer.

Sunday 20 November 2016

What Is Cancer?

Cancer is the name given to a collection of related diseases. In all types of cancer, some of the body’s cells begin to divide without stopping and spread into surrounding tissues.

The invasive
 breast cancer tumor 
shown here includes 
a cluster of slowly 
proliferating 
cells that resist 
chemotherapy 
reatment.


Cancer can start almost anywhere in the human body, which is made up of trillions of cells. Normally, human cells grow and divide to form new cells as the body needs them. When cells grow old or become damaged, they die, and new cells take their place.

When cancer develops, however, this orderly process breaks down. As cells become more and more abnormal, old or damaged cells survive when they should die, and new cells form when they are not needed. These extra cells can divide without stopping and may form growths called tumors.

Many cancers form solid tumors, which are masses of tissue. Cancers of the blood, such as leukemias, generally do not form solid tumors.

Cancerous tumors are malignant, which means they can spread into, or invade, nearby tissues. In addition, as these tumors grow, some cancer cells can break off and travel to distant places in the body through the blood or the lymph system and form new tumors far from the original tumor.

Unlike malignant tumors, benign tumors do not spread into, or invade, nearby tissues. Benign tumors can sometimes be quite large, however. When removed, they usually don’t grow back, whereas malignant tumors sometimes do. Unlike most benign tumors elsewhere in the body, benign brain tumors can be life threatening.

Differences between Cancer Cells and Normal Cells

Cancer cells differ from normal cells in many ways that allow them to grow out of control and become invasive. One important difference is that cancer cells are less specialized than normal cells. That is, whereas normal cells mature into very distinct cell types with specific functions, cancer cells do not. This is one reason that, unlike normal cells, cancer cells continue to divide without stopping.

In addition, cancer cells are able to ignore signals that normally tell cells to stop dividing or that begin a process known as programmed cell death, or apoptosis, which the body uses to get rid of unneeded cells.

Cancer cells may be able to influence the normal cells, molecules, and blood vessels that surround and feed a tumor—an area known as the microenvironment. For instance, cancer cells can induce nearby normal cells to form blood vessels that supply tumors with oxygen and nutrients, which they need to grow. These blood vessels also remove waste products from tumors.

Cancer cells are also often able to evade the immune system, a network of organs, tissues, and specialized cells that protects the body from infections and other conditions. Although the immune system normally 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 certain immune system cells that normally prevent a runaway immune response, cancer cells can actually keep the immune system from killing cancer cells.

Friday 11 November 2016

Kanser Otak : Ketahui Jenis2 Kanser Otak


Ketumbuhan pada bahagian tertentu di otak yang memberi implikasi yang teruk pada pesakitnya.

Jenis-Jenis Kanser Otak
  • Supratentorial (bahagian atas otak)
  • Infratentorial (bahagian bawah otak)
Kanser pada bahagian atas otak ialah:
  • Astrocytoma (ketumbuhan otak yang bukan berasal daripada sel-sel saraf);
  • Craniopharyngioma (juga dikenali sebagai tumor Rathke pouch); dan
  • kanser kelenjar pineal.
Kanser pada bahagian bawah otak ialah:
  • Infratentorial;
  • Medulloblastoma (belakang otak);
  • Cerebellar Astrocytoma (ketumbuhan pada serebrum);
  • Brainstem Glioma (pangkal otak);
  • Ependymoma (ketumbuhan serebral yang berasal daripada sel-sel ependimal slia. Ia menyekat cecair serebrospina dan menyebabkan hidrosefalus) jenis yang paling kerap berlaku.
Punca Kanser Otak
  • Genetik atau keturunan;
  • Radiasi pada otak; dan
  • Pesakit AIDS, leukemia, dan pesakit yang mengalami kegagalan buah pinggang.
Tanda-Tanda / Simptom

Pada peringkat bayi mereka akan mengalami:
  • Proses pertumbuhan yang tidak normal - tidak boleh merangkak walaupun berusia enam bulan;
  • Hidrosefalus (kepala besar) kerana meningkatnya tekanan pada kepala; dan
  • ubun-ubun membengkak, bayi akan gelisah, tidak bermaya dan kurang menyusu.
Pada peringkat awal kanak-kanak:
  • Mengadu sakit kepala berulang-ulang;
  • kelihatan letih dan tidak bertenaga;
  • prestasi pembelajaran menurun; dan
  • lebih menderita kerana tekanan dalam otak semakin tinggi.
Simptom yang lebih ketara:
  • Sakit kepala yang lebih teruk pada bahagian depan dan tepi kepala;
  • muntah yang memancut dan sakit kepala pada awal pagi;
  • sawan;
  • kejang pada tangan;
  • kabur penglihatan;
  • kanak-kanak yang menderita pada bahagian infratentorial tidak dapat berdiri atau berjalan dengan stabil;
Sekiranya kanser merebak pada brainstem (pangkal otak) kanak-kanak akan mengalami:
  • Gangguan pada pertuturan;
  • sistem pernafasan terganggu;
  • lemah anggota badan; dan
  • gangguan pada fungsi-fungsi saraf otak.