Germ cell tumours in men occur in >95% of cases in the testicles and are then referred to as testicular tumours, testicular carcinomas or simply testicular cancer.

In Germany, almost 4000 men are diagnosed with testicular cancer every year - and the trend is rising. This corresponds to approx. 1-2% of all cancers in men. The testicular tumour is a tumour disease that mainly affects young men between the ages of 20 and 40, where it is the most common tumour.

The causes of testicular cancer are not fully understood. However, it is known that men with undescended testicles, especially if they were corrected after puberty, have an increased risk of developing testicular cancer. A familial clustering and an association with genetic diseases have also been observed.

If you experience the following symptoms, you should urgently consult a doctor to clarify the cause:

• Nodular change in the testicles even without pain
• Enlargement of the testicles even without pain
• pulling testicular pain
• Pain in the groin area
• Feeling of heaviness in the testicles
• Breast growth on one or both sides

Although testicular cancer can theoretically be cured at any stage of the disease, the earlier the cancer is detected, the higher the chances of recovery, the easier the treatment and the fewer the side effects.

If you are suspected of having a testicular tumour, various examination procedures are necessary in order to make an accurate diagnosis. These include, for example, a physical examination, laboratory tests, an ultrasound scan and, if necessary, a computerised tomography (CT) scan. Additional examinations such as magnetic resonance imaging (MRI) or skeletal scintigraphy may also be necessary

Medical history and physical examination
During a detailed consultation, you will tell the doctor about all your symptoms and previous illnesses (including family hereditary diseases). You will then undergo a thorough physical examination. Your blood will be tested for certain tumour markers.

Sonography (ultrasound examination)
Sonography is a painless and radiation-free examination to detect a testicular tumour and any metastases. In addition to visualising the tumour in the testicle itself, it can also be used to detect the spread of the tumour to other organs (metastases), e.g. the liver

Computed tomography (CT)
Computed tomography is a special X-ray examination (with contrast medium) that scans the body layer by layer and can therefore visualise the exact location and size of any metastases in the abdomen or chest. However, very small metastases cannot be reliably detected with a CT scan, which is why the examination is often repeated at intervals of several months.

Magnetic resonance imaging (MRI)
MRI is not an X-ray examination, but is based on the effects of magnetic fields. The advantage over a CT scan is that the examination does not expose the patient to radiation. The disadvantages can be the very long duration of the examination and the difficult interpretation of the findings, which requires an experienced radiologist.

Skeletal scintigraphy (bone scintigraphy)
By administering a small amount of radioactive substance into the bloodstream, tumour metastases in the bones can be visualised. A special camera recognises the radioactively enriched areas in the diseased bone. This is a gentle examination in which the radiation decays quickly.

Tissue sample
The tissue sample is necessary in order to classify the tumour (tumour classification), i.e. to identify the degree of malignancy and characteristics of the tumour in order to develop a targeted tumour therapy. Tissue is usually harvested as part of the surgical removal of a testicle with a malignant tumour. It is rarely necessary to obtain tissue from a testicular carcinoma metastasis by means of a CT-supported biopsy from the abdominal cavity or by means of a thoracoscopy.

In order to be able to determine the most suitable therapy, it is necessary to determine exactly which histological subtype (tissue type) the testicular carcinoma corresponds to, what degree of differentiation (grading) it has and how far it has already spread (staging) before starting therapy. These three parameters can be used to determine the correct tumour stage.

- Fine tissue subtype

Testicular tumours can be divided into "seminomas" and "non-seminomas". Seminomas consist exclusively of seminoma cells, while non-seminomas can consist of a single tumour component (such as embryonal cell carcinoma, teratoma, chorionic carcinoma or a yolk sac tumour) or a combination of different tumour components. The therapy differs depending on the type of tumour tissue.

- S- Serum tumour markers

SX Serum tumour marker values not available or corresponding tests not performed.
S0 Serum tumour markers within normal limits
S1-S3 At least one of the serum tumour markers is elevated

(N = upper limit of the normal value for LDH)

-TNM

Tumour spread is determined by the TNM classification.

T stands for the size and extent of the primary tumour, N stands for the number of affected regional lymph nodes and M stands for the occurrence and localisation of distant metastases (tumour metastases).

TNM for testicular carcinomas

TNM classification of testicular carcinoma according to UICC 2017

Surgery

If there is an urgent suspicion of testicular cancer based on the examinations described above, the testicle must be surgically exposed via an incision in the groin area. The decision to completely remove the diseased testicle (orchiectomy) must then be made intraoperatively, possibly on the basis of a frozen section examination carried out by the pathologist. Regardless of the stage of the tumour, orchiectomy is almost always the treatment of first choice. Under certain circumstances, a biopsy of the second testicle is carried out at the same time to check the tumour. In around 95% of men, only one testicle is affected, in which case the remaining healthy testicle takes over the functions of the removed testicle. For this reason, unilateral testicular removal surgery has virtually no side effects.

After the surgical removal of the testicle, a precise histological classification of the tumour can be made and further treatment can be decided.

The tumour is classified into the histological subtypes seminoma (50-60%) and non-seminoma (40-50%).

Radiotherapy - chemotherapy

Radiotherapy, like chemotherapy, aims to destroy the cancer cells. A targeted concentration of radiation is used to damage the cancer cells while sparing the healthy tissue.

Seminomas

In the case of seminoma, if metastases are present, it may be necessary to carry out additional chemotherapy or, in individual cases, radiotherapy after removal of the testicle. While a decision must be made between radiotherapy and chemotherapy for smaller lymph node metastases in the abdominal cavity, chemotherapy is almost the only option for larger lymph node metastases in the abdominal cavity. Radiotherapy can be carried out on an outpatient basis and is generally well tolerated. Side effects such as nausea, vomiting and diarrhoea can be well controlled with appropriate medication. Sperm production is almost always only temporarily affected by radiotherapy. Chemotherapy at our clinic is usually given on an inpatient basis, but this depends on the type and duration of chemotherapy. The side effects of chemotherapy also depend on the type of medication and its dosage. In addition to nausea and vomiting, temporary hair loss, blood count changes and susceptibility to infections may occur. Impairment of sperm production during chemotherapy is also usually only temporary.

Even in the absence of metastases when a seminoma is diagnosed, chemotherapy or radiotherapy can be carried out once following surgical removal of the testicle, whereby a so-called "surveillance" strategy, i.e. controlled waiting with regular follow-up examinations, is usually used nowadays.

Non-seminomas

In the case of non-seminomas, chemotherapy consisting of several therapy cycles is usually required if metastases are present. Primary surgical removal of the lymph node tissue from the posterior abdominal cavity (=retroperitoneal lymphadenectomy) is now almost only carried out if teratoma tissue is suspected in the affected lymph node, which is known to be resistant to chemotherapy.

In the case of a non-seminoma without metastases in the CT diagnosis, a surveillance strategy or additional chemotherapy (1 cycle) is used depending on the T stage (pT1 vs. ≥pT2).

In advanced testicular carcinomas, a combination of surgery, chemotherapy and possibly radiotherapy is often necessary.

If a relapse (recurrence of the tumour) develops despite previous surgery, radiotherapy and/or chemotherapy, standard chemotherapy and high-dose chemotherapy can be initiated again. Under certain circumstances, a residual tumour can also be surgically removed.

The following aspects should be taken into account in follow-up care:

• Most recurrences occur in the first two years after the end of treatment.
• Late recurrences can also occur after more than five years, which is why annual follow-up is recommended for life.
• After surgical removal of the lymph nodes in the retroperitoneum, recurrences there are very rare.
• Computed tomography of the thorax is preferable to chest X-ray if there is a reasonable suspicion of recurrence.
• The results of recurrence therapy depend on the tumour volume, so early detection should be aimed for.
• After chemotherapy and radiotherapy, there is an increased risk of therapy-related secondary tumours and the so-called metabolic syndrome.

You can find tips on how to cope better with the disease on websites such as http://www.hodenkrebs.de/ or the website of the German Cancer Society(http://www.krebsgesellschaft.de).

More than 95% of patients can be cured if diagnosed and treated in good time. This makes testicular cancer one of the cancers with the best chances of recovery. The probability of recurrence/progression of the disease depends on the histological type, histopathological risk factors, the presence of metastases at the time of diagnosis and the level of tumour markers.