Testicular Germ Cell Tumour

Testicular germ cell tumours are the most common cancers affecting young men, but they are also among the most curable. Understanding this disease can help patients and families navigate diagnosis, treatment, and the path to recovery.

Table of contents

• What is testicular germ cell tumour?
• Types of testicular germ cell tumours
• Who is affected?
• Symptoms
• Risk factors
• Diagnosis
• Treatment
• Prognosis and survival
• Fertility considerations

What is testicular germ cell tumour?

A testicular germ cell tumour is a type of cancer that develops in the testicles from cells called germ cells, which are the cells that produce sperm^[1]. More than 90% of testicular cancers start in these germ cells^[4].

The testicles are part of the male reproductive system. When germ cells develop abnormally, they can form tumours. These tumours may be cancerous (malignant) or non-cancerous (benign)^[1]. Cancerous germ cell tumours can spread to other parts of the body if not treated^[1].

Although testicular germ cell tumours are rare in the general population, accounting for only 1% to 2% of all tumours in males, they are the most common cancer in men between the ages of 15 and 35^[4][6].

Types of testicular germ cell tumours

Testicular germ cell tumours are broadly divided into two main groups: seminomas and non-seminomas. Each type behaves differently and requires different treatment approaches^[1].

Seminomas

Seminomas are tumours that often grow and spread more slowly than non-seminomas^[1]. They typically affect men in their 30s to 60s, with the highest rates occurring between ages 30 and 44^[1]. There are two subtypes of seminoma: classic (typical) seminoma, which usually affects people between ages 25 and 45, and spermatocytic seminoma, which usually affects people aged 50 and older and grows slowly^[24].

Non-seminomas

Non-seminomas typically grow larger and spread more quickly than seminomas^[1]. They can develop from different types of cells, and many non-seminomas contain a mixture of cell types^[5]. The main types of non-seminomas include:

• Teratomas contain tissue like teeth, hair, muscle and bone. Mature teratomas are usually non-cancerous, while immature teratomas are typically cancerous and grow fast^[1].
• Yolk sac tumours contain cells similar to those in a developing embryo. These tumours are cancerous and spread quickly. They are the most common malignant germ cell tumour in children^[1].
• Embryonal cell carcinomas are rare, cancerous tumours that may exist alone or mixed with other tumour types^[1].
• Choriocarcinomas consist of cells that form the placenta during pregnancy. They are rare and cancerous^[1].

Mixed germ cell tumours

Some testicular tumours contain both seminoma and non-seminoma cells. These are called mixed germ cell tumours^[1]. Many germ cell tumours are mixed^[1]. When a tumour contains both types of cells, doctors usually treat it as a non-seminoma^[5].

Who is affected?

Testicular cancer is rare, affecting about 1 in 250 men^[20]. However, it is the most common cancer in males between the ages of 15 and 35^[4]. The incidence of testicular germ cell cancer has been rising in many countries, including Europe and the United States^[4].

The age at which testicular germ cell tumours occur varies by type. Seminomas most commonly affect men between ages 30 and 44, while non-seminomas can occur at younger ages^[1][11].

Although the incidence is increasing, there is encouraging news: testicular germ cell cancer has become a model of curable cancer, with cure rates approaching 95% for all patients and over 70% even for those with advanced disease^[11].

Symptoms

The most common symptom of testicular germ cell tumour is a firm lump or mass on the testicle^[20]. This lump is often painless^[1]. Other symptoms may include:

• Swelling in the testicle^[3]
• A feeling of heaviness in the testicles or scrotum^[24]
• A dull ache in the testicles or lower abdomen^[24]
• Pain or discomfort in the testicle or scrotum^[3]
• Back pain^[3]

Rarely, men may experience sudden, sharp pain in or around the testicles or blood in the semen^[24].

If the cancer has spread to other parts of the body, additional symptoms may occur, such as lumps in the neck, cough, shortness of breath, nausea and vomiting, or bone pain^[24].

Risk factors

Several factors can increase the risk of developing testicular germ cell tumours^[10]:

• Undescended testicle (cryptorchidism) is one of the main risk factors. This occurs when one or both testicles fail to move down into the scrotum before birth^[10].
• A family history of testicular cancer, particularly in a father or brother, increases risk^[10].
• A personal history of testicular cancer means a higher chance of developing cancer in the other testicle^[10].
• Men who are Caucasian have a higher risk compared to other ethnic groups^[4].
• Abnormally developed testicles can increase risk^[4].

Both inherited genetic factors and environmental factors appear to contribute to testicular germ cell tumour risk^[6].

Diagnosis

Diagnosing testicular germ cell tumours involves several steps. Doctors typically use a combination of physical examination, imaging tests, blood tests, and sometimes surgery^[12].

Physical examination

A doctor will perform a physical examination of the testicles to feel for any lumps or masses^[20].

Imaging tests

Ultrasound is often the first imaging test used. It creates pictures of the testicles using sound waves and can help determine whether a lump looks like cancer or not^[12]. Other imaging tests, such as CT scans (computerized tomography) or MRI scans (magnetic resonance imaging), may be used to see if cancer has spread to other parts of the body^[12].

Blood tests

Blood tests check for proteins called tumour markers that cancer cells may produce^[12]. The main tumour markers for testicular germ cell tumours are:

• Alpha-fetoprotein (AFP) is elevated in 40% to 60% of men with non-seminomas. Seminomas do not produce AFP^[10].
• Beta-human chorionic gonadotropin (beta-hCG) is found in about 14% of patients with early-stage pure seminomas and about half of patients with advanced seminomas. It is also elevated in 40% to 60% of men with non-seminomas^[10].
• Lactate dehydrogenase (LDH) is another marker measured before and after treatment^[10].

These markers play an important role in staging and monitoring the disease and are measured before the testicle is removed^[10].

Surgery and tissue examination

If a lump or mass could be cancer, surgery may be needed to remove it^[12]. The removed tissue is then sent to a laboratory for testing to determine whether it is cancer and what type of cancer it is^[12].

Treatment

Treatment for testicular germ cell tumours is highly effective, and the disease is often curable^[10]. The main treatments include surgery, chemotherapy, and radiation therapy. The specific treatment plan depends on the type and stage of the cancer^[12].

Surgery

Surgery to remove the affected testicle, called orchidectomy, is the main treatment for testicular cancer^[13]. This may be the only treatment needed, especially for early-stage disease^[13]. Removing one testicle does not usually affect a man’s ability to have erections, orgasms, or biological children^[24].

In some cases, surgery may also be needed to remove lymph nodes in the abdomen if cancer has spread there, or to remove tumours that have spread to the lungs^[13].

Chemotherapy

Chemotherapy uses strong medicines to kill cancer cells^[12]. It may be given after surgery to help prevent cancer from coming back, or if the cancer has spread to other parts of the body^[13]. Testicular germ cell tumours are particularly sensitive to platinum-based chemotherapy, which has dramatically improved survival rates^[6].

Radiation therapy

Radiation therapy uses high-energy rays to kill cancer cells^[13]. It may be used for certain types of testicular cancer, particularly seminomas, if cancer has spread to lymph nodes in the abdomen^[13]. Seminomas are very sensitive to radiation^[1].

Prognosis and survival

Testicular germ cell tumours have an excellent prognosis when treated appropriately^[20]. For patients with seminomas of all stages combined, the cure rate exceeds 90%^[10]. For patients with early-stage seminomas or non-seminomas, the cure rate approaches 100%^[10].

Several factors influence prognosis^[21]:

• Seminomas often respond better to treatment than non-seminomas and usually have a better prognosis^[21].
• Cancers that start in the testicle have a better prognosis than those that start outside the testicles^[21].
• Where the cancer spreads matters. Cancer that spreads only to lymph nodes in the abdomen or lungs has a better prognosis than cancer that spreads to other organs^[21].
• The level of tumour markers in the blood is important for non-seminomas. High tumour marker levels are linked with a poorer prognosis^[21].

Despite these variations, testicular germ cell cancer is highly treatable and needs to be diagnosed early and treated appropriately^[20].

Fertility considerations

Some treatments for testicular cancer, particularly chemotherapy, can affect fertility^[13]. Before starting treatment, men are offered the option to collect and store their sperm through a process called sperm banking^[13]. This stored sperm can later be used in fertility treatments if the person wishes to have biological children^[13].

Having one testicle removed typically does not affect fertility^[13]. However, fertility may already be reduced during the two years before testicular cancer is discovered, and the remaining testicle may not always function normally^[18].

• Testicles
• Scrotum
• Lymph nodes

testicular cancer, germ cell tumor, TGCT