This glossary defines the medical terms used throughout this book in plain language. Phonetic pronunciations are provided for difficult words. Terms are organized by category for easy reference.

Anatomy Terms Cancer and Pathology Terms Treatment Terms Lab and Imaging Terms Hormone and Medication Terms Research and Statistics Terms

Anatomy Terms

Adenocarcinoma(AD-eh-no-kar-sih-NO-muh)

Cancer that starts in glandular cells. The most common type of prostate cancer.

Adrenal glands(uh-DREE-nul)

Small glands on top of each kidney that produce small amounts of male hormones (androgens).

Anus(AY-nus)

The opening at the end of the rectum through which stool leaves the body.

Apex(AY-peks)

The bottom (lower) part of the prostate, closest to the urinary sphincter.

Base

The top (upper) part of the prostate, closest to the bladder.

Bladder

The hollow organ that stores urine before it leaves the body.

Bladder neck

The area where the bladder connects to the urethra, at the top of the prostate.

Capsule

The thin outer layer of tissue that surrounds the prostate gland.

Corpora cavernosa(KOR-por-uh kav-er-NO-suh)

Two sponge-like chambers in the penis that fill with blood during an erection.

Ejaculatory ducts

Tubes that carry semen through the prostate to the urethra.

Epididymis(ep-ih-DID-ih-mis)

A coiled tube behind each testicle where sperm mature and are stored.

Lymph nodes

Small, bean-shaped structures throughout the body that filter fluid and help fight infection. Cancer can spread to lymph nodes.

Neurovascular bundles(NUR-oh-VAS-kyoo-lur)

Bundles of nerves and blood vessels that run along both sides of the prostate and control erections.

Obturator lymph nodes(OB-too-ray-tor)

Lymph nodes in the pelvis that are commonly checked during prostate cancer surgery.

Pelvic floor

The group of muscles at the bottom of the pelvis that support the bladder, bowel, and urinary sphincter.

Perineum(pair-ih-NEE-um)

The area of skin between the scrotum and the anus.

Prostate gland(PROSS-tate)

A walnut-sized gland below the bladder and in front of the rectum that produces fluid that is part of semen.

Rectum

The last section of the large intestine, located behind the prostate.

Seminal vesicles(SEM-ih-nul VESS-ih-kulz)

Two small glands behind the prostate that produce most of the fluid in semen.

Sphincter(SFINK-ter)

A ring of muscle that controls the flow of urine. There are two — one internal (involuntary) and one external (voluntary).

Testes / Testicles(TESS-teez / TESS-tih-kulz)

The two male reproductive glands in the scrotum that produce sperm and testosterone.

Urethra(yoo-REE-thruh)

The tube that carries urine from the bladder through the prostate and penis to the outside of the body.

Vas deferens(VAS DEF-er-enz)

The tube that carries sperm from the testicle to the ejaculatory duct.

Cancer and Pathology Terms

Androgen(AN-droh-jen)

Any male hormone, including testosterone and dihydrotestosterone (DHT). Most prostate cancers need androgens to grow.

Androgen receptor(AN-droh-jen ree-SEP-tor)

A protein on prostate cells that androgens attach to, signaling the cell to grow.

Apoptosis(ay-pop-TOH-sis)

Programmed cell death — the normal process by which old or damaged cells die. Cancer cells often lose this ability.

Basal cell carcinoma

A rare type of prostate cancer arising from basal cells rather than glandular cells.

Benign(beh-NINE)

Not cancer. A benign growth does not spread to other parts of the body.

Benign prostatic hyperplasia (BPH)(hy-per-PLAY-zhuh)

Non-cancerous enlargement of the prostate, common in older men.

Biomarker

A measurable substance in the body (blood, urine, or tissue) that provides information about cancer — its presence, aggressiveness, or likely response to treatment.

BRCA1 / BRCA2(BRAK-uh)

Genes that normally help repair DNA. Mutations in these genes increase the risk of several cancers, including prostate cancer.

Capsular penetration

See Extracapsular extension.

Castration-resistant prostate cancer (CRPC)

Prostate cancer that continues to grow despite very low testosterone levels from hormone therapy.

Castration-sensitive prostate cancer (CSPC)

Prostate cancer that still responds to hormone therapy (androgen deprivation).

Cribriform pattern(KRIB-rih-form)

A specific growth pattern seen under the microscope in which cancer cells form sieve-like structures. Associated with more aggressive behavior.

Dihydrotestosterone (DHT)(dy-HY-droh-tess-TOSS-teh-rone)

A potent form of testosterone made from testosterone by the enzyme 5-alpha reductase. Drives prostate cell growth.

Ductal adenocarcinoma

A less common, often more aggressive variant of prostate cancer.

Extracapsular extension (ECE)

Cancer that has grown through the prostate capsule into surrounding tissue.

Gleason score

A grading system for prostate cancer based on how the cancer cells look under a microscope. Two pattern numbers (each 3–5) are added together for a total score (6–10).

Grade Group (GG)

A simplified version of the Gleason score, ranging from 1 (least aggressive) to 5 (most aggressive):

GG 1 = Gleason 3+3 = 6
GG 2 = Gleason 3+4 = 7
GG 3 = Gleason 4+3 = 7
GG 4 = Gleason 8
GG 5 = Gleason 9–10

High-grade prostatic intraepithelial neoplasia (HGPIN)

Abnormal-looking cells in the prostate that are not cancer but may indicate increased risk.

Intraductal carcinoma of the prostate (IDC-P)

Cancer growing within the ducts of the prostate. Associated with aggressive disease.

Lymphovascular invasion (LVI)

Cancer cells found inside blood vessels or lymph channels in the tissue. May indicate higher risk of spread.

Malignant(muh-LIG-nunt)

Cancerous. A malignant tumor can invade nearby tissue and spread to other parts of the body.

Margin

The edge of tissue removed during surgery. A "positive margin" means cancer cells are found at the very edge, suggesting some cancer may remain. A "negative margin" means no cancer at the edge.

Metastasis(meh-TAS-tuh-sis)

The spread of cancer from where it started to another part of the body (plural: metastases).

Multifocal

Cancer present in more than one area of the prostate at the same time.

Mutation

A change in the DNA of a cell. Some mutations drive cancer growth; others are harmless.

Neuroendocrine differentiation

When prostate cancer cells develop features of neuroendocrine cells. Associated with aggressive behavior and resistance to hormone therapy.

Oligometastatic(OL-ih-go-met-uh-STAT-ik)

A state where cancer has spread to only a few sites (usually ≤5), potentially still curable or controllable with targeted treatment.

Perineural invasion (PNI)(pair-ee-NUR-ul)

Cancer cells found growing along or around nerves in the biopsy tissue.

Primary tumor

The original cancer — where it first started growing.

Sarcoma(sar-KO-muh)

A rare type of cancer arising from connective tissue (muscle, fat) rather than glandular cells.

Small cell / neuroendocrine carcinoma

A rare, aggressive type of prostate cancer that does not produce much PSA and does not respond well to hormone therapy.

Squamous cell carcinoma (SCC)

A rare type of prostate cancer arising from squamous (flat) cells.

Staging

The process of determining how far cancer has spread. See TNM staging.

TNM staging

A system that describes cancer extent:

T (Tumor) = size and extent of the primary tumor
N (Nodes) = whether cancer has spread to nearby lymph nodes
M (Metastasis) = whether cancer has spread to distant sites

Transitional cell carcinoma

Cancer arising from the cells lining the urethra or bladder that can sometimes involve the prostate.

Tumor volume

The amount (percentage or size) of cancer found in the prostate.

Treatment Terms

Active surveillance (AS)

A management strategy for low-risk prostate cancer involving regular monitoring (PSA, exams, biopsies, MRI) with the intent to treat if the cancer progresses.

Adjuvant therapy(AD-joo-vunt)

Additional treatment given after the primary treatment (usually surgery) to reduce the risk of cancer returning.

Androgen deprivation therapy (ADT)

Treatment that lowers male hormone levels or blocks their effect. Also called hormone therapy.

Antiandrogen

A drug that blocks the effect of male hormones on cancer cells (e.g., bicalutamide, enzalutamide, apalutamide, darolutamide).

Bilateral orchiectomy(or-kee-EK-toh-mee)

Surgical removal of both testicles to eliminate the main source of testosterone. A permanent form of ADT.

Brachytherapy(BRAK-ee-THER-uh-pee)

Radiation treatment using radioactive seeds or sources placed directly into or near the prostate.

LDR (low-dose rate): Permanent seed implants that deliver radiation slowly over weeks to months.
HDR (high-dose rate): Temporary catheters placed in the prostate through which a high-activity source delivers radiation in one or a few sessions.

Chemotherapy

Drugs that kill rapidly dividing cells, including cancer cells. Common agents for prostate cancer include docetaxel and cabazitaxel.

Cryotherapy / Cryoablation(KRY-oh-uh-BLAY-shun)

Treatment that destroys cancer by freezing it with extremely cold gases.

CyberKnife (CK)

A brand of robotic radiosurgery system used to deliver SBRT.

External beam radiation therapy (EBRT)

Radiation delivered from a machine outside the body, aimed at the cancer.

Focal therapy

Treatment that targets only the area of the prostate containing cancer, rather than the entire gland.

Fractionation

Dividing the total radiation dose into smaller daily doses (fractions).

Conventional fractionation: ~44 treatments over ~9 weeks
Moderate hypofractionation: ~20–28 treatments over ~4–6 weeks
Ultra-hypofractionation / SBRT: ~5 treatments over ~1–2 weeks

GnRH agonist(AG-oh-nist)

A drug that initially stimulates, then suppresses testosterone production (e.g., leuprolide, goserelin). Requires an initial "flare" blocker.

GnRH antagonist(an-TAG-oh-nist)

A drug that directly suppresses testosterone production without an initial flare (e.g., degarelix, relugolix).

HIFU(HIGH-foo)

High-intensity focused ultrasound — a focal therapy that uses focused sound waves to heat and destroy cancer tissue.

Hormone therapy

See Androgen deprivation therapy.

Immunotherapy

Treatment that helps the immune system recognize and attack cancer cells (e.g., sipuleucel-T, pembrolizumab).

Image-guided radiation therapy (IGRT)

Using imaging (CT, X-ray, ultrasound) during each radiation treatment to ensure accurate targeting.

Intensity-modulated radiation therapy (IMRT)

An advanced form of EBRT that shapes radiation beams to conform to the target while minimizing dose to surrounding tissues.

Intermittent ADT (iADT)

Hormone therapy given in cycles (on and off) rather than continuously, to reduce side effects.

Lymph node dissection (LND)

Surgical removal of lymph nodes to check for cancer spread. Also called lymphadenectomy.

Metastasis-directed therapy (MDT)

Treatment (usually radiation or surgery) aimed specifically at a small number of metastatic sites.

Neoadjuvant therapy(NEE-oh-AD-joo-vunt)

Treatment given before the primary treatment (e.g., hormone therapy before radiation).

Nerve-sparing surgery

A surgical technique that attempts to preserve the neurovascular bundles alongside the prostate to maintain erectile function.

Observation / Watchful waiting

Monitoring cancer without active treatment, with the intent to manage symptoms if they develop, rather than to cure. Different from active surveillance.

PARP inhibitor

A targeted drug that blocks a DNA repair enzyme (PARP), effective in cancers with specific DNA repair gene mutations (e.g., BRCA1/2). Examples: olaparib, rucaparib.

Proton beam therapy

A type of EBRT that uses protons instead of X-rays. Protons stop at a specific depth, potentially reducing dose to tissues beyond the target.

Radical prostatectomy (RP)

Surgery to remove the entire prostate gland and seminal vesicles.

Open: Through a large incision in the abdomen or perineum.
Laparoscopic: Through several small incisions using long instruments.
Robotic-assisted (RARP): Laparoscopic surgery performed with a robotic system (e.g., da Vinci).

Radiopharmaceutical

A radioactive drug injected into the body that targets cancer cells. Examples: Lutetium-177 PSMA (¹⁷⁷Lu-PSMA-617), Radium-223.

Salvage therapy

Treatment given after the primary treatment has failed or cancer has recurred.

SBRT (stereotactic body radiation therapy)

Highly focused radiation delivered in very few treatments (usually 5) at high doses per fraction.

Simulation (sim)

The planning session before radiation therapy where imaging is done to map the treatment area.

SpaceOAR / Rectal spacer

A hydrogel injected between the prostate and rectum before radiation to push the rectum away and reduce radiation side effects.

TURP (transurethral resection of the prostate)

Surgery to remove prostate tissue blocking urine flow, performed through the urethra. Used for BPH, not cancer treatment.

Lab and Imaging Terms

Bone scan (technetium-99m)

A nuclear medicine test that detects areas of increased bone activity, which may indicate cancer spread to bones.

CT scan (computed tomography)

An imaging test that uses X-rays to create detailed cross-sectional images of the body.

Decipher

A genomic test performed on prostate tissue that predicts the risk of cancer spreading (metastasis).

DRE (digital rectal exam)

A physical exam in which the doctor inserts a gloved finger into the rectum to feel the prostate for abnormalities.

ExoDx (EPI)

A urine-based biomarker test that helps predict whether a prostate biopsy will find significant cancer.

4Kscore

A blood test combining four kallikrein proteins with clinical information to predict the risk of aggressive prostate cancer.

Free PSA

The percentage of PSA in the blood that is not bound to proteins. A lower percentage may suggest cancer.

MRI (magnetic resonance imaging)

An imaging test that uses magnets and radio waves to create detailed pictures of the prostate and surrounding structures.

Multiparametric MRI (mpMRI)

An MRI that combines multiple imaging sequences (T2-weighted, diffusion-weighted, dynamic contrast-enhanced) for detailed prostate evaluation.

Oncotype DX Prostate

A genomic test on biopsy tissue that helps predict cancer aggressiveness.

PCA3

A urine biomarker specific to prostate cancer that helps determine the need for biopsy.

PET scan (positron emission tomography)

An imaging test that uses a radioactive tracer to detect metabolically active cells, including cancer.

PHI (Prostate Health Index)

A blood test combining three forms of PSA to improve cancer detection accuracy.

PI-RADS (Prostate Imaging Reporting and Data System)

A scoring system (1–5) used to rate the likelihood that an MRI finding is clinically significant cancer:

PI-RADS 1–2: Cancer unlikely
PI-RADS 3: Equivocal
PI-RADS 4: Cancer likely
PI-RADS 5: Cancer very likely

Prolaris

A genomic test that measures cell cycle progression genes to predict cancer aggressiveness.

PSA (prostate-specific antigen)

A protein produced by the prostate gland. Elevated levels in the blood may indicate cancer, BPH, infection, or other conditions.

PSA density

PSA level divided by prostate volume (from imaging). Helps distinguish cancer from BPH in men with large prostates.

PSA doubling time (PSADT)

The time it takes for the PSA level to double. A shorter doubling time suggests more aggressive cancer.

PSA velocity

The rate of PSA change over time (ng/mL per year).

PSMA PET (prostate-specific membrane antigen PET)

A PET scan using a tracer that binds to PSMA, a protein found on most prostate cancer cells. More sensitive than conventional imaging.

SelectMDx

A urine-based biomarker test that helps predict the presence of high-grade prostate cancer.

SUV (standardized uptake value)

A measure of how much radioactive tracer is absorbed by a tissue on PET scan. Higher values may suggest cancer.

Hormone and Medication Terms

5-alpha reductase inhibitor (5-ARI)

A drug that blocks the conversion of testosterone to DHT (e.g., finasteride, dutasteride). Used for BPH and studied for cancer prevention.

Abiraterone(uh-BIR-uh-teh-rone)

A drug that blocks androgen production in the testes, adrenal glands, and tumor itself. Used with prednisone.

Apalutamide(uh-PAL-oo-tuh-mide)

A next-generation antiandrogen used in non-metastatic and metastatic castration-resistant prostate cancer.

Bicalutamide(by-kuh-LOO-tuh-mide)

An older antiandrogen often used short-term to prevent testosterone flare with GnRH agonists.

Cabazitaxel(kab-AZ-ih-TAX-el)

A chemotherapy drug used after docetaxel for advanced prostate cancer.

Darolutamide(dar-oh-LOO-tuh-mide)

A next-generation antiandrogen used in non-metastatic and metastatic castration-sensitive prostate cancer.

Degarelix(deh-gah-REL-iks)

A GnRH antagonist given as a monthly injection.

Docetaxel(DOH-seh-TAX-el)

A chemotherapy drug commonly used for advanced prostate cancer.

Enzalutamide(en-zah-LOO-tuh-mide)

A next-generation antiandrogen used across multiple stages of prostate cancer.

Goserelin(GO-seh-rel-in)

A GnRH agonist given as an implant under the skin.

Leuprolide(loo-PRO-lide)

A GnRH agonist given as an injection (monthly, every 3 months, or every 6 months).

Lutetium-177 PSMA (¹⁷⁷Lu-PSMA-617)

A radiopharmaceutical that delivers radiation directly to PSMA-expressing cancer cells. Brand name: Pluvicto.

Olaparib(oh-LAP-uh-rib)

A PARP inhibitor used for prostate cancer with specific DNA repair gene mutations.

PDE5 inhibitor (PDE5i)

Drugs used to treat erectile dysfunction by increasing blood flow to the penis (e.g., sildenafil/Viagra, tadalafil/Cialis).

Pembrolizumab(pem-broh-LIZ-oo-mab)

An immunotherapy drug (checkpoint inhibitor) used for cancers with specific biomarkers (MSI-high or TMB-high).

Radium-223(RAY-dee-um)

A radiopharmaceutical that targets bone metastases by mimicking calcium.

Relugolix(rel-OO-go-lix)

An oral GnRH antagonist (pill form) for hormone therapy.

Sipuleucel-T(sih-poo-LOO-sel-T)

An immunotherapy vaccine made from the patient's own immune cells. Brand name: Provenge.

Tadalafil(tah-DAL-uh-fil)

A PDE5 inhibitor used for erectile dysfunction and sometimes for penile rehabilitation after treatment.

Research and Statistics Terms

Biochemical recurrence (BCR)

A rise in PSA after treatment that suggests cancer may be returning, even before it can be seen on imaging.

Confidence interval (CI)

A range of values within which the true result is likely to fall. A 95% CI means there is a 95% chance the true value is within that range.

Control group

The group in a clinical trial that receives the standard treatment (or placebo) for comparison with the experimental treatment.

Cumulative incidence

The probability of an event (e.g., recurrence) occurring over a specific time period, accounting for competing risks.

Disease-free survival (DFS)

The length of time after treatment during which no cancer is detected.

Double-blind

A study design where neither the patient nor the doctor knows who is receiving the experimental treatment versus the placebo.

Hazard ratio (HR)

A measure of how often an event (e.g., death, recurrence) occurs in one group compared to another. HR 1 means higher risk.

Kaplan-Meier curve

A graph that shows the probability of survival (or another outcome) over time.

Median

The middle value in a set of numbers. Half the patients did better, half did worse.

Metastasis-free survival (MFS)

The length of time after treatment during which cancer has not spread to distant sites.

Number needed to treat (NNT)

The number of patients who need to receive a treatment for one additional patient to benefit.

Overall survival (OS)

The length of time from diagnosis or treatment that patients are still alive.

p-value

A statistical measure of whether a result is likely due to chance. A p-value 0.05 is generally considered statistically significant.

Placebo(pluh-SEE-bo)

An inactive treatment (e.g., sugar pill) used in clinical trials for comparison.

Progression-free survival (PFS)

The length of time during and after treatment that cancer does not grow or spread.

Prospective study

A study that follows patients forward in time from the start of the study.

Randomized controlled trial (RCT)

A study where patients are randomly assigned to different treatment groups. Considered the gold standard of medical evidence.

Retrospective study

A study that looks back at data already collected.

Statistically significant

A result that is unlikely to have occurred by chance alone (usually p 0.05). Does not necessarily mean clinically important.