If you’ve been told that your prostate cancer may have reached the seminal vesicles, you may be wondering whether surgery is still possible. In selected men without distant spread, robotic radical prostatectomy may still be considered as part of treatment aimed at long-term cancer control.
Your specialist will consider your PSA, Grade Group, scans, lymph nodes, overall health and treatment priorities. Because seminal vesicle invasion increases recurrence risk, you may also need radiotherapy, hormone therapy or both later, although further treatment is not automatic.
What Are the Seminal Vesicles?
Your seminal vesicles are two small glands behind your prostate that produce fluid forming part of semen. Because they sit close to your prostate, prostate cancer can sometimes grow into them.
During radical prostatectomy, your surgeon removes the prostate and usually the seminal vesicles. Afterwards, you will no longer produce semen and cannot father a child naturally. If future fertility matters to you, ask about sperm banking before treatment. Your testes will continue to produce testosterone.
What Does Seminal Vesicle Invasion Mean?
Seminal vesicle invasion means prostate cancer has grown locally from the prostate into one or both seminal vesicles. This is classed as T3b disease and is a form of locally advanced prostate cancer.
T3b does not automatically mean your cancer is metastatic. If scans show no distant spread, you may still have treatment with curative intent.
Does Seminal Vesicle Invasion Automatically Rule Out Robotic Surgery?
No. Seminal vesicle invasion does not automatically rule out radical prostatectomy. If surgery is appropriate for you, a robotic-assisted approach may still be used when your team believes long-term cancer control is realistic.
Your MDT will consider your PSA, Grade Group, MRI, other staging scans, lymph-node status and general health rather than deciding from the T3b label alone.
What Is the Difference Between Suspected T3b and pT3b?
Before surgery, MRI and other clinical information may suggest T3b disease, meaning possible seminal vesicle invasion. This is a pre-treatment assessment rather than pathological confirmation.
After surgery, your pathology report may show pT3b if the pathologist confirms cancer in your seminal vesicles. The “p” means the stage has been confirmed by examining the removed tissue.
How Do T3b, N0, N1 and M0 Affect Your Treatment?
Your staging results help your team understand how far your cancer appears to have spread and which treatments may still be suitable for you.
| Finding | What It Means | Why It Matters |
| Suspected T3b | Pre-treatment assessment suggests seminal vesicle invasion | Helps guide treatment planning before surgery |
| pT3b | Seminal vesicle invasion has been confirmed by pathology after prostate removal | Indicates a higher pathological risk of recurrence and influences follow-up |
| cN0 | No regional lymph-node metastases have been identified on clinical staging | Surgery may remain an option in appropriately selected locally advanced disease |
| pN0 | No cancer was found in the regional lymph nodes that were removed and examined | Provides more definitive pathological nodal information |
| N1 | Prostate cancer has spread to regional pelvic lymph nodes | Can change the need for additional treatment |
| M0 | No distant metastases have been identified | Curative-intent local treatment may still be considered |
| M1 | Distant metastatic disease has been identified | Treatment usually focuses on systemic therapy and other appropriate metastatic-disease treatments rather than radical prostatectomy as standard local treatment |
Your specialist considers these findings together with your PSA, Grade Group, overall health and treatment preferences rather than using T3b stage alone to choose treatment.
How Does MRI Help Identify Seminal Vesicle Invasion?
Your MRI helps your doctors see whether your prostate cancer may have grown into your seminal vesicles. This information helps your team decide whether radical prostatectomy could be suitable and plan the operation if surgery is chosen.
MRI is useful, but it is not perfect. Evidence summarised in the European Association of Urology guidelines found that MRI had a sensitivity of about 58% and specificity of about 96% for detecting seminal vesicle invasion. In practical terms, this means MRI can identify many suspicious cases, but small or microscopic areas of invasion may still be missed. The final pathology after surgery provides more definitive information.
Why Does Your Biopsy Grade Matter?
Your biopsy Grade Group helps show how aggressive your prostate cancer may be, while seminal vesicle involvement shows how far it has grown. Your doctors use both when deciding whether robotic surgery is suitable for you.
They will also consider your PSA, MRI and overall cancer stage. Being classed as T3b does not by itself decide whether surgery is right for you.
Why Is Lymph-Node Staging Important?
If your cancer has reached your seminal vesicles, your doctors will also check whether it has spread to nearby lymph nodes. Your scans and, if needed, lymph-node removal during surgery can help assess this.
If cancer is found in the pelvic lymph nodes, your treatment plan may change and additional hormone therapy, radiotherapy or both may need to be discussed.
Does a PSMA PET/CT Affect the Decision?
Your doctor may recommend a PSMA PET/CT to check whether your prostate cancer has spread to your lymph nodes, bones or other areas. This can give your team more detailed information when planning your treatment.
If PSMA PET/CT identifies distant metastatic disease, radical prostatectomy would not usually be standard treatment, and your specialist will discuss systemic and other appropriate treatment options. If the cancer remains localised or locally advanced, surgery may still be considered for you.
Evidence Note
The prospective proPSMA trial studied 302 men with high-risk prostate cancer being considered for curative treatment. PSMA PET/CT had an overall staging accuracy of 92% compared with 65% for conventional CT and bone scanning.
It also changed planned management in 28% versus 15% of men. However, very small cancer deposits can still be missed.
What Happens to the Seminal Vesicles During Surgery?
During robotic prostate surgery, your surgeon usually removes your seminal vesicles along with your prostate. If seminal vesicle invasion is suspected, your surgeon may need to remove a wider area of tissue around the cancer to achieve appropriate cancer clearance.
The prostate and seminal vesicles are then sent to the laboratory for detailed examination. This helps your team confirm whether cancer has actually reached the seminal vesicles and plan your follow-up treatment.
Can Nerve-Sparing Surgery Still Be Possible?
Nerve sparing may still be possible in some cases, but it depends on where the cancer is located and how likely it is to have extended towards the nerves on each side of your prostate. Your surgeon may be able to preserve the nerves on one side while taking a wider margin on the other.
Cancer control comes first. If there is a significant risk that cancer has reached the tissue beside a neurovascular bundle, preserving that nerve may not be oncologically appropriate.
How Can Seminal Vesicle Invasion Change the Operation?
Because T3b cancer extends beyond the prostate, your surgeon may need to use a wider dissection than would be required for organ-confined disease. This can affect decisions about nerve sparing and the surgical margins your surgeon aims to achieve.
However, this does not mean you cannot have robotic surgery. If your cancer can be safely removed, your surgeon may still recommend it as part of your overall treatment plan.
Is Surgery Better Than Radiotherapy for T3b Prostate Cancer?
There is no good evidence that radical prostatectomy is better than radiotherapy for everyone with T3b prostate cancer. NICE considers both options appropriate for selected people with locally advanced disease when long-term cancer control is realistic.
If you choose radiotherapy, hormone therapy is usually given alongside it. If you choose surgery, your pathology and postoperative PSA may later show that additional treatment should be discussed. Speaking with both a surgeon and a clinical oncologist can help you compare these options.
Why Might Surgery Be Part of Multimodal Treatment?
If your prostate cancer has reached the seminal vesicles, surgery may be one part of a wider treatment plan. Your specialist will use your results after surgery to decide whether you need additional treatment.
- Radical Local Treatment: Surgery removes your prostate and seminal vesicles as part of radical treatment for the cancer within and immediately surrounding the prostate.
- Detailed Pathology: Examining the removed tissue gives your doctors more information about your cancer stage, Grade Group, margins and lymph nodes.
- PSA Monitoring: Your PSA after surgery helps your specialist assess whether cancer may remain or return.
- Additional Treatment: You may need radiotherapy, hormone therapy or both if your results suggest a higher risk of recurrence.
You will not automatically need further treatment simply because your cancer has reached the seminal vesicles. Your specialist will consider your pathology and PSA together to plan the next steps for you.
What Does the Final Pathology Show After Surgery?
After your surgery, your prostate and seminal vesicles are examined to confirm whether cancer has reached the seminal vesicles. Your report also gives details about your Grade Group, stage, margins and lymph nodes.
If cancer is confirmed in your seminal vesicles, your cancer is classified as pT3b. This can increase your risk of recurrence, but it does not mean your cancer will definitely return.
Research Insight
A nationwide population-based study examined 1,371 men with pT3b prostate cancer after radical prostatectomy and compared them with 4,063 men with pT3a disease. Seminal vesicle invasion was associated with a higher risk of prostate-cancer progression and death than extraprostatic extension alone. However, prostate-cancer-specific survival among men with pT3b disease was still about 94% at six years.
This shows that pT3b carries a higher risk than pT3a, although many men in this surgical cohort still had favourable disease-specific survival. As an observational study, it cannot show that surgery is better than other treatments.
Why Are Surgical Margins Particularly Important?
Your surgical margin shows whether cancer cells reach the inked surgical surface of the removed tissue. A negative margin is more reassuring, while a positive margin can increase your risk of recurrence.
A positive margin does not mean cancer is definitely left behind. Your doctors will consider it alongside your stage, Grade Group, lymph nodes and PSA.
What Should Happen to PSA After Surgery?
After your prostate and seminal vesicles are removed, your PSA should fall to a very low or undetectable level. An undetectable PSA is reassuring, but if your final pathology confirms pT3b disease, regular PSA monitoring remains particularly important because recurrence risk is higher.
If PSA remains detectable or begins to rise, your team will consider the PSA trend alongside your pathology when deciding whether further investigation or treatment is needed.
Will You Automatically Need Radiotherapy After Surgery?
No. Having pT3b disease does not automatically mean you need radiotherapy after surgery.
Many people can initially be monitored with PSA testing, with early salvage radiotherapy discussed if PSA becomes detectable or begins to rise. The decision also depends on your Grade Group, margins, lymph nodes and other high-risk pathology, so some particularly high-risk cases may need an earlier discussion with a clinical oncologist.
Could You Need Hormone Therapy After Surgery?
You may need hormone therapy after surgery, but seminal vesicle invasion alone does not mean you will need it. Your PSA, Grade Group, lymph nodes and other pathology findings will help guide the decision.
Hormone therapy may be discussed alongside radiotherapy in selected higher-risk situations. Your specialist will explain whether it could benefit you and how long treatment may be needed.
UK Guidance Note
NICE recommends offering radical prostatectomy or radical radiotherapy to suitable people with CPG 4 or 5 localised or locally advanced prostate cancer when long-term cancer control is considered possible. Patients who are candidates for radical treatment should have the opportunity to discuss treatment options and serious side effects with both a specialist surgical oncologist and a specialist clinical oncologist.
For CPG 2–5 disease treated with radical external-beam radiotherapy, NICE recommends androgen deprivation therapy alongside radiotherapy. NICE recommends six months of ADT and says treatment lasting up to three years can be considered for CPG 4 and 5 disease after discussing the benefits and risks.
What Should You Ask Before Choosing Robotic Surgery?
Ask your specialist whether surgery is suitable for you and whether your lymph nodes need further assessment. You can also ask whether nerve sparing is realistic and whether you may need radiotherapy or hormone therapy afterwards.
You should also ask how your PSA will be monitored after surgery and what your treatment plan could look like if your final pathology confirms pT3b disease.
Myth vs Fact
| Myth | Fact |
| Seminal vesicle invasion means prostate cancer is automatically metastatic. | Seminal vesicle invasion is classified as T3b locally advanced prostate cancer. It does not by itself mean that cancer has spread to distant lymph nodes, bones or other organs. |
| If cancer has reached the seminal vesicles, robotic prostate surgery is no longer possible. | Radical prostatectomy may still be considered in selected patients with non-metastatic locally advanced disease, usually with the understanding that additional treatment may be needed. |
| A PSMA PET/CT can rule out every microscopic area of spread. | PSMA PET/CT is more accurate than conventional imaging for higher-risk staging, but very small cancer deposits can still be missed. |
| pT3b disease automatically means you need immediate radiotherapy after surgery. | Seminal vesicle invasion increases recurrence risk, but postoperative treatment also depends on PSA, margins, Grade Group and lymph-node findings. Many patients can initially be monitored and receive early salvage treatment if PSA rises. |
| If your PSA becomes undetectable, you no longer need follow-up. | An undetectable PSA is reassuring, but regular PSA monitoring remains important because pT3b disease carries a higher recurrence risk. |
| Seminal vesicle invasion means surgery has failed. | pT3b describes how far the cancer had grown before it was removed. It increases recurrence risk but does not show by itself that cancer remains after surgery. |
Key Takeaways
- Seminal vesicle invasion is T3b locally advanced prostate cancer, but it does not automatically mean your cancer is metastatic.
- Radical prostatectomy may still be an option if your cancer remains suitable for treatment aimed at long-term control.
- MRI and PSMA PET/CT can improve staging but cannot exclude every microscopic area of cancer spread.
- Nerve sparing depends on where your cancer is located and whether it can be performed safely.
- Your final pathology and postoperative PSA help determine whether you need monitoring or additional treatment.
- pT3b increases recurrence risk, but it does not mean your cancer will definitely return or require immediate further treatment.
Frequently Asked Questions
1. Can You Have Robotic Prostate Surgery If Cancer Has Reached the Seminal Vesicles?
Yes. Radical prostatectomy may still be considered if your cancer remains suitable for treatment aimed at long-term control. Your PSA, Grade Group, scans, lymph nodes and general health will help guide the decision.
2. What Does Seminal Vesicle Invasion Mean?
It means prostate cancer has grown into one or both seminal vesicles. This is T3b locally advanced disease, but it does not automatically mean your cancer is metastatic.
3. Does T3b Prostate Cancer Automatically Rule Out Surgery?
No. Surgery may still be considered when your team believes long-term cancer control is realistic, although you may also need additional treatment.
4. Can an MRI Show If Cancer Has Reached Your Seminal Vesicles?
MRI can suggest seminal vesicle invasion but may miss microscopic disease. Your pathology after surgery provides more definitive information.
5. Can You Still Have Nerve-Sparing Surgery With Seminal Vesicle Invasion?
Possibly. Nerve sparing depends on where your cancer is located and whether preserving the nerves is oncologically safe for you.
6. Will You Automatically Need Radiotherapy After Surgery?
No. Your PSA, Grade Group, surgical margins, lymph nodes and other pathology findings will help determine whether radiotherapy is needed.
7. Could You Need Hormone Therapy After Robotic Prostate Surgery?
You may need hormone therapy in some higher-risk situations, particularly if radiotherapy is recommended. Seminal vesicle invasion alone does not determine this.
8. What Does pT3b Mean on Your Pathology Report?
pT3b means pathology has confirmed cancer in the seminal vesicles. It increases recurrence risk but does not mean your cancer will definitely return.
9. What Should Happen to Your PSA After Surgery?
Your PSA should fall to a very low or undetectable level. You will then need regular PSA monitoring, particularly if pT3b disease is confirmed.
10. Does Seminal Vesicle Invasion Mean Your Cancer Will Come Back?
No. It increases your recurrence risk, but your pathology and postoperative PSA help your specialist assess your individual risk more accurately.
Final Thoughts: Understanding Robotic Prostate Surgery for Seminal Vesicle Invasion
If your prostate cancer has reached the seminal vesicles, robotic surgery may still be an option for you. Your specialist will consider your scans, PSA, Grade Group, lymph nodes and overall health when deciding whether surgery could form part of your treatment.
If you are considering robotic prostate surgery in London, you can contact Prostate Clinic London to discuss your results, treatment options and whether a consultation may be appropriate for you.
References:
- National Institute for Health and Care Excellence (NICE) (2021) Prostate cancer: diagnosis and management. NICE guideline NG131. Published 9 May 2019; last updated 15 December 2021. Available at: https://www.nice.org.uk/guidance/ng131
- University College London Hospitals NHS Foundation Trust (2026) Robotic prostatectomy. Last updated 4 March 2026. Available at: https://www.uclh.nhs.uk/patients-and-visitors/patient-information-pages/robotic-prostatectomy
- Parker, C.C. et al. (2024) ‘Timing of radiotherapy (RT) after radical prostatectomy (RP): long-term outcomes in the RADICALS-RT trial (NCT00541047)’, Annals of Oncology, 35(7), pp. 656–666. Available at: https://pubmed.ncbi.nlm.nih.gov/38583574
- The Royal College of Pathologists (2024) G084 Dataset for histopathology reports for prostatic carcinoma. October 2024. Available at: https://www.rcpath.org/resourceLibrary/g084-dataset-for-histopathology-reports-for-prostatic-carcinoma.html
- Kristiansen, A., Drevin, L., Delahunt, B., Samaratunga, H., Robinson, D., Franck Lissbrant, I., Stattin, P. and Egevad, L. (2017) ‘Prognostic significance and biopsy characteristics of prostate cancer with seminal vesicle invasion on radical prostatectomy: a nationwide population-based study’, Pathology, 49(7), pp. 715-720. Available at: https://pubmed.ncbi.nlm.nih.gov/29037803
- Hofman, M.S., Lawrentschuk, N., Francis, R.J. et al. (2020) ‘Prostate-specific membrane antigen PET-CT in patients with high-risk prostate cancer before curative-intent surgery or radiotherapy (proPSMA): a prospective, randomised, multicentre study’, The Lancet, 395(10231), pp. 1208–1216. Available at: https://pubmed.ncbi.nlm.nih.gov/32209449
- European Association of Urology (EAU) (2026) EAU Guidelines on Prostate Cancer. Available at: https://uroweb.org/guidelines/prostate-cancer