In testicular seminoma radiotherapy, the crucial step is deciding when radiation still belongs in care and how the nodal field should be drawn once that decision is made. After radical inguinal orchiectomy, post-operative management depends on histology and disease extent, and this chapter keeps radiation in a defined role mainly for pure seminoma.
This detailed article reorganizes the practical planning points from the chapter into a single clinical read. For the broader framework, see our Target Volume Delineation and Field Setup – Complete Clinical Guide. If you want to compare the same contouring logic with another abdominal disease site already covered on the blog, read our guide to pancreatic cancer target delineation.
General principles of planning and target delineation in testicular seminoma
The chapter starts with a firm sequence. In almost every case, initial management of testicular cancer begins with radical inguinal orchiectomy. What follows depends on histologic subtype and on stage. Post-operative radiation is presented as a realistic option for pure seminoma, the most common testicular germ cell tumor and the most radiosensitive one, while non-seminomatous germ cell tumors are described as uncommon candidates for radiation.
That distinction matters because the staging workup has to prove that the disease really is pure seminoma before planning moves forward. The chapter asks for a detailed history and physical examination, serum AFP, β-hCG, and LDH, a chemistry panel, testicular ultrasound, and chest x-ray. After radical inguinal orchiectomy for pure seminoma, tumor markers should be repeated, and additional staging should include CT of the chest, abdomen, and pelvis, with brain MRI only when indicated. The authors also add a practical point that belongs in every consultation rather than in an afterthought: any patient being planned for testicular cancer treatment should be offered fertility evaluation and sperm banking.
That opening section is useful because it keeps contouring anchored to the right clinical question. First confirm the subtype, then define the stage, then decide whether the patient stays on surveillance, receives para-aortic adjuvant radiation, or needs a broader nodal field for stage II disease. The planning tables make sense only after that sequence is respected.
Nodal drainage patterns, laterality, and the effect of prior surgery
Laterality changes the expected pattern of spread in seminoma, so it also changes the geometry of the field. Right-sided seminoma tends to drain to paracaval, precaval, and aortocaval nodes. Left-sided seminoma tends to drain to lateroaortic and preaortic nodes. The chapter does not treat that as background anatomy. It uses laterality as a direct planning variable.
There is also an important exception to the classic retroperitoneal pattern. Patients with prior scrotal or inguinal surgery may carry risk in pelvic, external iliac, or inguinal nodes. The chapter brings that warning in early because it eventually changes the field recommendation itself: the ipsilateral inguinal and iliac regions should be included when prior surgery has altered the usual pathway.
The stage I figure from the chapter makes that logic easy to see. Axial slices are displayed from superior to inferior with CTV in red and PTV in blue, tracking how the field relates to the aorta and inferior vena cava. It is not just an illustration of treated anatomy. It is a visual explanation of why the para-aortic strip is built from vascular contours and then expanded with fixed planning margins.
This is one of the more useful planning reminders in the chapter. A seminoma field cannot be treated as a prefabricated rectangle. Side of origin and prior surgical approach both reshape nodal risk, and the chapter keeps returning to those two variables when it moves from general principles to field design.
Stage I testicular seminoma: surveillance first, para-aortic strip when radiation is selected
For stage I pure seminoma, the chapter is explicit that post-orchiectomy surveillance is strongly preferred. Adjuvant radiation becomes an option when surveillance is refused, supported by the MRC TE10 and TE18 trials, and the target in that setting is the para-aortic nodal strip alone. The dose range is 20 to 25.5 Gy in 1.5 to 2.0 Gy fractions, provided there has been no prior inguinal or scrotal violation.
The chapter also names another non-inferior adjuvant approach, namely 1 to 2 cycles of carboplatin. Still, when radiation is chosen, the practical value lies in how the treatment volume is described. Table 27.1 translates that recommendation into contouring steps and landmark-based borders.
Table 27.1. Suggested target volumes for stage I testicular seminoma
The chapter defines the stage I field in two parallel ways: by CT-based vascular anatomy and by bony-anatomic landmarks. Both describe the same para-aortic treatment concept.
| Target volume | Definition based on CT imaging and vascular anatomy (Fig. 27.1) | Definition based on anatomic landmarks |
|---|---|---|
| CTV |
Contour the inferior vena cava and aorta from 2 cm below the top of the kidney superiorly down to the bifurcation of the iliac vessels inferiorly. Expand the inferior vena cava contour by 1.2 cm and the aortic contour by 1.9 cm. Combine both volumes and then subtract bone, muscle, and bowel. |
Superior border: top of T11. Some cited sources recommend the top of T12 [6]. Inferior border: bottom of L5. Lateral borders: edge of the transverse processes, typically about 10 cm in width. |
| PTV [20-25.5 Gy in 1.5-2.0 Gy per fraction] |
Expand the final CTV by 0.5 cm + 0.7 cm to block edge. |
For left-sided seminoma, nodal mapping studies suggest that covering the left renal hilum may be optional [7]. |
Source: Target Volume Delineation and Field Setup, 2nd Edition (Table 27.1)
The vascular method keeps the retroperitoneal field precise. The aorta and inferior vena cava are first outlined over the craniocaudal extent defined in the table. The two vessels then receive different expansions, 1.9 cm for the aorta and 1.2 cm for the inferior vena cava, before bone, muscle, and bowel are subtracted. Only after that is the PTV created with the 0.5 cm expansion plus 0.7 cm to block edge.
The landmark-based method expresses the same field in a way that is easy to reproduce at the machine: top of T11, or T12 in some sources, superiorly; bottom of L5 inferiorly; and lateral width aligned with the transverse processes. One of the more nuanced points in the table is the left renal hilum note. The chapter does not make left hilar coverage mandatory for every left-sided case. It frames it as an optional decision supported by nodal mapping data.
That combination of restraint and precision captures the stage I message well. The field is limited to the para-aortic region, the dose is modest, and the emphasis stays on an anatomically faithful strip rather than on unnecessarily broad prophylactic coverage.
Stage II testicular seminoma: dogleg field design, conedown boost, and total doses of 30 to 36 Gy
Stage II pure seminoma is approached differently. Instead of a para-aortic strip alone, the chapter recommends a dogleg field. Dose selection is straightforward: 30 Gy for stage IIA and 36 Gy for stage IIB. The authors also accept primary chemotherapy as an alternative, typically etoposide and cisplatin with or without bleomycin for 3 to 4 cycles.
The planning structure becomes more layered in this setting. One component follows the retroperitoneal and iliac vessels. A second component covers gross nodal disease starting from the GTV. Those two pieces are combined into the initial CTV, and a separate boost volume is then created for the visible adenopathy. Table 27.2 lays out that workflow in a form that is easy to follow at the contouring station.
Table 27.2. Suggested target volumes for stage II testicular seminoma
For stage II disease, the chapter expands beyond para-aortic coverage and integrates visible nodal disease into the plan. The table below reproduces the target volumes and dose structure described by the authors.
| Target volume and dose | Definition based on CT imaging and vascular anatomy (Fig. 27.2) | Definition based on anatomic landmarks |
|---|---|---|
| Initial vessel CTV |
Create the same inferior vena cava and aortic contours and expansions used in Table 27.1. Then contour the common iliac vessels, proximal internal iliac vessels until the takeoff of the superior gluteal artery, and the external iliac vessels down to the upper border of the acetabulum. Expand those vessels by 1.2 cm while respecting anatomic boundaries. |
Superior border: top of T11. Some cited sources recommend the top of T12 [6]. |
| Nodal CTV |
Contour gross nodal disease (GTV) and expand it by 0.8 cm while respecting anatomic boundaries. |
Inferior border: top of the acetabulum. Some cited sources recommend the middle or bottom of the obturator foramen [6]. |
| Initial CTV |
Combine the vessel CTV and nodal CTV to form the initial CTV. |
Lateral border: tips of the transverse processes of the lumbar vertebrae, typically around L3 with attention to kidney location, extending inferiorly to cover the lateral acetabular edge. |
| Initial PTV [20-25.5 Gy in 1.5-2.0 Gy per fraction] |
Expand the initial CTV by 0.5 cm + 0.7 cm to block edge. |
For left-sided seminoma, nodal mapping studies suggest that left renal hilar coverage may be optional [7]. |
| Nodal PTV [boost conedown volume to a total of 30-36 Gy in 2 Gy per fraction] |
Expand the nodal CTV by 0.5 cm + 0.7 cm to block edge. |
Maintain a 2 cm margin around all visible gross adenopathy, following the principle shown in Fig. 27.3. |
Source: Target Volume Delineation and Field Setup, 2nd Edition (Table 27.2)
The lower dogleg slices illustrate how far the field extends once iliac coverage is required. The plan follows the common iliac vessels, the proximal internal iliac vessels until the superior gluteal takeoff, and the external iliac vessels down to the upper acetabular border. When gross adenopathy is present, the chapter does not rely on rough inclusion. It asks for a dedicated GTV contour, a 0.8 cm expansion to create the nodal CTV, and then a further 0.5 cm + 0.7 cm to block edge for the boost PTV.
The landmark description keeps the field reproducible. Superiorly, the border remains at the top of T11, with a note that some sources choose T12. Inferiorly, the field reaches the top of the acetabulum, although other cited sources use the middle or bottom of the obturator foramen. Laterally, the field is tied to the transverse processes of the lumbar vertebrae, typically around L3, adjusted for kidney position and continued to the lateral acetabular edge at the lower end of the field.
Clinically, this is where the chapter moves from elective retroperitoneal treatment to a two-level plan that includes visible nodal burden. The initial dogleg field covers the pathways at risk, and the conedown boost brings the gross nodal volume to 30 to 36 Gy in 2 Gy fractions depending on stage.
Simulation, immobilization, and field setup details
The simulation instructions are concrete. At the authors’ institution, standard simulation for testicular seminoma uses 2 mm CT slice thickness with the patient supine and arms up. An alpha cradle is used for immobilization. Intravenous contrast is often used for stage II patients to help define gross nodal disease. If a staging PET scan is available, it can be fused with the simulation CT.
The contralateral intact testicle should be shielded with a clamshell. For treatment delivery, the chapter describes 3D-CRT as the standard approach for seminoma, using AP/PA fields based on bony anatomic landmarks or vascular anatomy. That choice matches the rest of the chapter, which is organized around practical margins and reproducible field borders rather than around a more complex technique.
The chapter also gives a clear adjustment for altered drainage after prior surgery. If there has been inguinal or scrotal surgery, the ipsilateral inguinal and iliac regions should be included in the field. If the scrotum was penetrated, an electron boost to the scrotum and scar should be considered. That recommendation matters because it corrects the field for a surgically modified pattern of spread rather than assuming classic retroperitoneal drainage in every patient.
Read from start to finish, the chapter follows a clean planning logic. Stage I pure seminoma favors surveillance but still allows a tightly defined para-aortic strip when radiation is the chosen adjuvant path. Stage II uses a dogleg field, integrates visible nodal disease, and escalates total dose according to IIA or IIB status. Laterality guides nodal expectations, prior surgery changes field extent, and simulation parameters make the whole approach reproducible.
References used in the chapter
The recommendations summarized here are grounded in the NCCN testicular cancer guideline version 2.2020, the MRC TE10 and TE18 trials for the stage I adjuvant setting, the radiotherapy planning paper by Wilder and colleagues, and the nodal mapping studies cited for retroperitoneal and pelvic topography. The reference list in the chapter also includes the seminoma nodal metastasis mapping study by Paly and colleagues and the pelvic lymph node topography work by Dinniwell and colleagues.
