2.7 Male Reproductive System: Testicular Cancer Cheat Sheet (DRAFT) by Molly

Testicular cancer presen­tation will often be via a painless swelling, or mass in the scrotum. Sometimes there is localised discomfort or pain, with an associated heaviness.

The testicles (testes) are two small, oval-s­haped organs located behind the penis in a skin sack called the scrotum.

The testicles are located outside the body because sperm develop best at a temper­ature several degrees cooler than normal internal body temper­ature.

The leydig cells distri­buted throughout the testicle are the body's main source of testos­terone. Testos­terone, the male sex hormone, is essential to the develo­pment of the reprod­uctive organs and other male charac­ter­istics such as body and facial hair, low voice, and wide shoulders. Without enough testos­terone, a man will probably lose his sex drive and suffer from fatigue, depres­sion, hot flashes and osteop­orosis.

The lymphatics directly from the testes follow the spermatic cord, through the inguinal ring, along the iliac nodes and to the para-a­ortic nodal chain. These lymphatic chains ultimately determine the radiation fields.

Testicular tumours are relatively rare, repres­enting approx­imately 1% of all cancers.

It is associated with crypto­rch­idism, which is maldescent of the testes from the abdomen. There is an increased risk 10 to 40 times higher.

The breakdown of the tumour types expected for testicular tumours are 95 % Germinal, and the remainder non-ge­rminal.

70 % of germinal tumours are seminoma, and the rest are teratomas.

Seminoma are sensitive to radiation and often present early at stage 1 where an Orchid­ectomy is performed and then prophy­lactic para-a­ortic node irradi­ation is delivered.

Seminoma is very predic­table in its spread, and at presen­tation regional lymph nodes will be present in 25 % of cases for seminoma, 40 % for teratomas, and 50 % for embryonal carcin­omas.

General - history and physical examin­ation

Medical Imaging - Testicular ultrasound is the first procedure for scrotal abnorm­ality, followed by chest imaging and CT of the abdome­n/p­elvis to assess nodal involv­ement.

The complete removal means an accurate diagnosis can be made through histop­ath­ology and the primary disease has been removed from the patient.

There are a number of staging systems used for testicular cancers.

The Marsden system, it is broken up into 4 stages.

For non-se­minomas and patients with advanced disease, a radical orchid­ectomy and chemot­herapy will be admini­stered.

Radiot­herapy will not play a role in the management unless there is a large residual mass postch­emo­the­rapy.

The radiation fields that are used to treat testicular cancer will be dependent upon the disease stage, the admini­str­ation of chemot­herapy and the radiation oncolo­gist’s prefer­ence.

For early stage disease only the para-a­ortic nodal group is irradi­ated.

With bulky disease in the para-a­ortic it is possible that the contra­lateral pelvis will be irradiated - an “inverted Y” technique. There will be a central pelvic shield to minimise toxicity to the bladder and bowel.

The energy can be dependent on the patients’ AP separa­tion, ranging from 6 to 18 MV.

The radiation fields are designed based on the patient’s lymphatic chains. Everyone’s lymphatics are slightly different, so we need to know where they are.

The Lower level is at the top of the obturator foramen, but there is no need to include the surgical scar within the field unless the is a testis capsule was compro­mised and there risk of seeding. The radiation oncologist may like to see a radio-­opaque marker along the scar so that it is visualised on CT. Most often that not, the LL will run about half way through the scar

If the radiation oncologist has prescribed radiation to the abdomen only, similar inform­ation to the dog-leg technique will need to be acquired.

The inform­ation to be acquired at simula­tio­n/p­lanning for both the dog-leg and para-a­ortic techniques are essent­ially the same, as follows:

-Stretch TOX (Tip of xiphi-­ste­rnum) to UBP (upper border of pubis)

-A planning CT throughout the treatment volume will be acquired. This will be used to delineate the kidney volume and the field definition for the patient.

It is unlikely that we will treat above the diaphragm for testicular cancer. If we were to treat a residual mass, the field dimensions are:

The planning for these patients is not usually complex, as the technique is just opposed photon fields.

Figure A (lower image) is a DRR of a patient that was planned for a dog-leg technique for Seminoma. Notice the long field length, the heavy shielding (repre­sented by the horizontal lines), and the partial irradi­ation of the kidneys can be seen in the upper planning images. There is a higher risk of disease on the ipsila­teral side within the para-a­ortic region, so there is greater coverage on that side. Notice how there is slightly more kidney within the field on the right side compared to the left.

The isocentre is in the correct position;
The dose is even across the treatment volume;
Dose to critical structures - Left and right kidneys;
Correct field size, monitor units, patient position, TD used in the calcul­ations
Once the plan has been checked, and everything is satisf­actory, the patient is ready to commence treatment.

Since the tumour type is partic­ularly sensitive to radiation, large doses do not need to be prescr­ibed.

If there is a persistent mass, then a boost will be delivered to an extra 5 - 10 Gy.

-The contra­lateral testes - probably the most sensitive.
-Kidneys - will be shielded as much as possible while covering the nodal groups.
-Bowel - can’t do much about this - medication as required.

Usually a FBE (Full blood examin­ation) will be performed at simulation to establish a baseline on blood counts. Bloods will then be taken weekly through out the treatment from there.

Acute side effects: Signif­icant erythema is not expected, due to the low doses, nausea and diarrhoea are extreamly likely due to the sheer size of the fields, some tiredness may be experi­enced after about two weeks of treatment.

Weekly imaging will be a minimum for these patients; many clinical centres may acquire images each fraction

Late toxicities:

Peptic ulcers

Gastritis (a group of conditions with one thing in common: inflam­mation of the lining of the stomach.)

Sperma­tog­enesis impari­ment.

The radiation oncologist will follow up the patient around six weeks post completion of the radiation therapy.