5.6 Reproductive System Tumors: Prostate, Cervix & Related Sites

Prostate Cancer

The prostate surrounds the proximal urethra just below the bladder neck and is divided into three glandular zones on imaging and pathology:

Key diagnostic and prognostic tools:

• PSA (prostate-specific antigen) — a serum glycoprotein used for screening, risk stratification, and post-treatment monitoring; rising PSA after treatment (biochemical recurrence) can precede clinically detectable disease by months to years.
• Gleason score / Grade Group — histologic grading based on the two most prevalent glandular patterns (each scored 1–5, summed to a Gleason score 6–10); higher scores indicate less differentiated, more aggressive disease. Grade Group 1 (Gleason ≤6) is low risk; Grade Group 5 (Gleason 9–10) is high risk.
• Risk stratification combines PSA, Gleason/Grade Group, and clinical T-stage (NCCN low/intermediate/high risk) to guide treatment intensity — active surveillance for low-risk disease up to dose-escalated external beam radiation with androgen deprivation therapy (ADT) for high-risk disease.
• Anatomic relationships drive planning constraints: the rectum lies immediately posterior (limiting posterior dose), the bladder sits superior/anterior, and the penile bulb/neurovascular bundles are considered for late toxicity. Rectal and bladder filling protocols (e.g., empty rectum, comfortably full bladder) reduce organ motion and improve day-to-day setup reproducibility.
• Low-dose-rate (LDR) or high-dose-rate (HDR) brachytherapy is used alone for favorable-risk disease or as a boost combined with external beam radiation for intermediate/high-risk disease, exploiting the prostate's compact, accessible geometry for interstitial implantation.

Cervical Cancer

The cervix is the lower, narrow portion of the uterus connecting to the vagina. Cervical cancer is overwhelmingly associated with persistent high-risk HPV infection (types 16 and 18 most common), and most cases are SCC (with adenocarcinoma as the next most common histology).

• FIGO staging for cervical cancer is based on clinical and imaging assessment of local extent (parametrial/vaginal involvement), nodal status, and distant spread, and is central to selecting treatment.
• Early-stage, small tumors may be managed surgically; locally advanced cervical cancer (bulky Stage IB3 and above) is treated with definitive chemoradiation — external beam radiation to the pelvis (and, when involved, para-aortic nodes) with concurrent weekly cisplatin, followed by an intracavitary brachytherapy boost.
• Brachytherapy is essential, not optional, in curative cervical cancer treatment: it delivers a highly conformal dose boost to the cervix and central pelvis that external beam alone cannot safely achieve, and omitting it is associated with significantly worse local control and survival.
• Lymphatic drainage proceeds from parametrial nodes to external/internal iliac and obturator nodes, then to common iliac and para-aortic nodes — the rationale for extended-field radiation when pelvic or para-aortic nodes are involved.

Endometrial Cancer

Endometrial (uterine corpus) cancer is the most common gynecologic malignancy in developed countries and is generally diagnosed early due to postmenopausal bleeding as a presenting symptom. Standard management is surgery first (total hysterectomy with bilateral salpingo-oophorectomy and staging), with adjuvant radiation reserved for higher-risk features (deep myometrial invasion, high grade, lymphovascular invasion, cervical stromal involvement). Adjuvant treatment is most often vaginal cuff brachytherapy alone for many intermediate-risk cases, reserving pelvic external beam radiation for higher-risk or node-positive disease — a contrast with cervical cancer, where external beam plus brachytherapy is standard for locally advanced disease.

Vulvar and Vaginal Cancer

Vulvar and vaginal cancers are less common gynecologic sites, predominantly SCC, and also linked to HPV. Vulvar cancer drainage proceeds to the inguinofemoral nodes, which must be electively covered even in early disease because of the high risk of nodal metastasis relative to primary tumor size. Vaginal cancer treatment (definitive chemoradiation with brachytherapy boost, similar in concept to cervical cancer) depends on the location within the vagina, since upper-vaginal tumors drain like cervical cancer (pelvic nodes) while lower-vaginal tumors drain like vulvar cancer (inguinal nodes).

Testicular Cancer

Testicular cancer is the most common malignancy in men aged 15–35 and is broadly divided into seminoma and non-seminomatous germ cell tumors (NSGCT). Seminoma is notably radiosensitive; historically, adjuvant radiation to the para-aortic (and sometimes pelvic) nodes was standard for early-stage seminoma after orchiectomy, though surveillance and single-agent chemotherapy have reduced radiation's role due to concern for long-term secondary malignancy and cardiovascular risk in young survivors. Lymphatic drainage follows the testicular vessels to the para-aortic (retroperitoneal) nodes, not the inguinal nodes — an important distinction from most other genital skin/scrotal malignancies, because the testis develops retroperitoneally and descends with its blood/lymphatic supply intact.

Reproductive Site Comparison

Recognizing that reproductive-organ lymphatic drainage follows embryologic origin (e.g., testis draining to para-aortic nodes despite its final scrotal location) is a recurring exam concept that distinguishes true anatomic drainage from apparent surface location.