The OCN (Oncology Certified Nurse) is a nursing certification awarded by ONCC.
ONCC publishes the official exam outline, eligibility rules and fees — see ONCC's official page before you book.
Twenty OCN (Oncology Certified Nurse) questions, with the answers hidden until you want them — covering Management, Pathology, Basics, Pharmacology and more. They are real cards from our 1050-card deck, not the 30 on the free preview page, so you can use both. Work through them cold, then use your score below to decide what to study next. ONCC publishes the official exam outline — check it for the real blueprint.
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A 62-year-old patient with pancreatic cancer undergoes a Whipple procedure. According to 2026 evidence-based guidelines, what is the recommended duration for post-operative venous thromboembolism (VTE) prophylaxis?
Show answer →Extended prophylaxis with Low Molecular Weight Heparin (LMWH) for 28 days (4 weeks) is the gold standard for major abdominal or pelvic surgery in oncology. Cancer patients have a 4x higher risk of VTE. Rationale: The hypercoagulable state of malignancy combined with major surgical trauma persists well beyond hospital discharge. Exam Tip: ONCC often tests the 4-week duration specifically for abdominal/pelvic oncology surgeries, as shorter durations are associated with high rates of post-discharge VTE.
Following an axillary lymph node dissection (ALND), a patient reports a heavy sensation and tightness in the arm, but no visible edema is present. What is the most appropriate nursing intervention?
Show answer →Referral to a Certified Lymphedema Therapist (CLT) for baseline measurements and Stage 0 (subclinical) management. Stage 0 lymphedema involves impaired lymphatic transport where symptoms (heaviness, aching) precede visible swelling. Early intervention with compression and exercise can prevent progression to Stage I or II. Exam Tip: Do not wait for measurable swelling to initiate a referral; patient-reported heaviness is a clinically significant early warning sign on the OCN exam.
A patient 3 days post-radical neck dissection has milky-white drainage in the suction bulb totaling 300 mL in 24 hours. What is the priority nutritional intervention to manage this complication?
Show answer →Initiate a low-fat diet supplemented with Medium-Chain Triglycerides (MCT). This patient has a chyle leak (thoracic duct injury). MCTs are absorbed directly into the portal venous system, bypassing the lymphatic system, which reduces chyle flow and allows the leak to heal. If output exceeds 500 mL/day, NPO and Total Parenteral Nutrition (TPN) may be required. Exam Tip: Identify chyle leaks by the milky appearance (post-feeding) and high triglyceride levels in the drainage fluid.
A patient post-low anterior resection (LAR) for rectal cancer develops new-onset tachycardia (118 bpm) and vague pelvic pain on post-op day 4. Temperature is 99.1°F. Which complication should the nurse suspect first?
Show answer →Anastomotic leak. Tachycardia is often the earliest and most sensitive sign of a leak, frequently appearing before fever, leukocytosis, or clear signs of peritonitis. In oncology patients, the inflammatory response may be blunted due to prior radiation or steroids. Exam Tip: On the OCN exam, unexplained tachycardia in a post-GI surgery patient is a red flag for a leak. Rapid surgical consultation and CT with contrast are typically the next steps.
A neutropenic patient (ANC 450) post-splenectomy has a surgical site that is painful and tender, but lacks redness or pus. How does the nurse interpret this finding?
Show answer →The absence of redness (erythema) and pus (suppuration) is expected in neutropenic patients because they lack sufficient white blood cells to mount a visible inflammatory response. Localized pain and fever may be the only indicators of a Surgical Site Infection (SSI). Exam Tip: In immunocompromised oncology patients, never dismiss a site because it doesn't look infected. Pain in a neutropenic patient is a primary indicator of underlying infection.
An 80-year-old patient with lung cancer is agitated and disoriented 48 hours after a lobectomy. After ensuring adequate oxygenation, what is the priority nursing action for delirium management?
Show answer →Perform a medication review to identify and discontinue deliriogenic drugs (e.g., benzodiazepines, anticholinergics, meperidine) and assess for metabolic triggers like hypercalcemia or hyponatremia. Use the Confusion Assessment Method (CAM) for screening. Rationale: Post-operative delirium in elderly oncology patients is often multifactorial. Exam Tip: Avoid physical restraints and PRN sedatives (which worsen delirium); focus on treating the underlying physiological cause.
A patient who received bevacizumab (VEGF inhibitor) 21 days ago undergoes an emergency bowel resection. On post-op day 10, the wound edges begin to separate. What is the pharmacological rationale?
Show answer →Bevacizumab inhibits Vascular Endothelial Growth Factor (VEGF), which is essential for angiogenesis and wound healing. Guidelines recommend a 6 to 8-week interval between the last dose of bevacizumab and elective surgery to minimize dehiscence risk. For post-op resumption, wait at least 28 days and ensure the wound is fully healed. Exam Tip: Targeted therapies like VEGF inhibitors significantly delay wound healing; this is a high-yield OCN topic regarding surgical timing.
A patient post-mastectomy has a surgical drain removed. Two days later, a soft, fluctuant, non-tender mass is noted under the incision area. What is the most likely complication and its management?
Show answer →Seroma. A seroma is a sterile collection of serous fluid in the dead space created by surgery. Management involves observation if small, or needle aspiration using sterile technique if the seroma is large, causing tension on the wound, or causing discomfort. Exam Tip: Differentiate from a hematoma, which typically occurs within 24 hours of surgery, is firm, and is often painful with skin discoloration (bruising).
A patient with a BRCA1 mutation asks why they are at increased risk for cancer. What is the primary pathological mechanism of the BRCA1 protein?
Show answer →BRCA1 and BRCA2 are tumor suppressor genes that encode proteins essential for homologous recombination (HR), a high-fidelity pathway for repairing double-strand DNA breaks. When these genes are mutated (germline), the cell must rely on error-prone repair mechanisms (like non-homologous end joining), leading to genomic instability and malignant transformation. Key Exam Point: This follows the two-hit hypothesis, where a germline mutation is present in all cells, but cancer only develops after a second somatic hit or mutation occurs in the wild-type allele.
Pathology results for a colorectal tumor show a loss of MSH2 and MSH6 protein expression via immunohistochemistry (IHC). What syndrome is most likely, and what is the mechanism?
Show answer →Lynch Syndrome (HNPCC). The loss of MSH2/MSH6 expression indicates a deficiency in the DNA Mismatch Repair (MMR) system. MMR genes (MLH1, MSH2, MSH6, PMS2) correct errors that occur during DNA replication. Deficiency leads to the accumulation of mutations, specifically in microsatellites (short, repetitive DNA sequences). Clinical Pearl: MSH2 and MSH6 often form a heterodimer; thus, a mutation in MSH2 typically results in the degradation of both proteins on IHC, whereas an MSH6 mutation may only result in the loss of MSH6.
A 25-year-old patient is diagnosed with an osteosarcoma. Their history includes a sibling with a brain tumor and a mother with early-onset breast cancer. Which gene is most likely affected?
Show answer →TP53 (Li-Fraumeni Syndrome). TP53 is a tumor suppressor gene known as the guardian of the genome because it regulates the cell cycle, DNA repair, and apoptosis (programmed cell death). Mutations in TP53 allow cells with damaged DNA to proliferate. Exam Strategy: Remember the SBLA mnemonic for the core cancers in Li-Fraumeni: Sarcoma, Breast, Leukemia, and Adrenal cortical carcinoma. LFS is characterized by an exceptionally high lifetime risk of multiple primary cancers, often at very young ages.
A Phase II trial is designed to evaluate a new T-cell engager for relapsed/refractory myeloma. What is the pivotal focus of this phase?
Show answer →Phase II trials focus on Efficacy and further safety assessment in a specific disease population (usually 25-100 patients). The goal is to determine if the drug has enough activity (signal-finding) to justify a large-scale Phase III trial. Exam Strategy: Phase II often uses Objective Response Rate (ORR) as a primary endpoint. If the drug does not meet a pre-specified response threshold, the trial stops. ONCC may ask about Go/No-Go decisions, which occur here.
In a Phase III randomized controlled trial (RCT), what is the role of the Control Arm, and what does the Gold Standard endpoint typically represent?
Show answer →Phase III trials compare the experimental treatment against the current Standard of Care (SOC) or a placebo (if no SOC exists). The goal is to confirm clinical benefit and support FDA approval. The Gold Standard endpoint is Overall Survival (OS), defined as the time from randomization until death from any cause. Exam Strategy: Remember that Phase III requires large populations (hundreds to thousands) and randomization to minimize bias. It is the pivotal phase for regulatory submission.
During a Phase I trial, a patient develops Grade 3 neurotoxicity. If this event prevents further dose escalation in that cohort, what is the specific term for this event?
Show answer →This is a Dose-Limiting Toxicity (DLT). A DLT is a severe, pre-defined toxicity occurring during a specific window (usually the first cycle) that is attributed to the study drug. DLTs are used to calculate the Maximum Tolerated Dose (MTD), which is the highest dose where a specified small fraction of patients experience a DLT. Exam Strategy: The MTD is usually one dose level below the level where the DLT threshold was exceeded. ONCC may ask how the Recommended Phase II Dose (RP2D) is determined—it is derived from the Phase I MTD and safety data.
A 48-year-old premenopausal woman has a 5-year Gail Model risk of 2.5%. She is interested in pharmacologic risk reduction for breast cancer. Which agent is the gold standard for this patient, and what is the minimum risk threshold for intervention?
Show answer →Tamoxifen (20 mg daily for 5 years) is the standard for premenopausal women. The ASCO/NCCN guidelines and the ONCC blueprint emphasize a 5-year Gail Model risk score of ≥1.7% as the threshold for discussing chemoprevention. Rational: Tamoxifen is a SERM that reduces the risk of ER+ invasive breast cancer by ~50%. It is the only FDA-approved agent for premenopausal risk reduction. Exam Tip: Note that the Gail Model does not account for paternal history or lobular carcinoma in situ (LCIS) as effectively as other models (like Tyrer-Cuzick), but 1.7% remains the magic number for the OCN exam.
A 62-year-old postmenopausal patient with a history of deep vein thrombosis (DVT) seeks breast cancer chemoprevention. Why are Aromatase Inhibitors (AIs) preferred over Selective Estrogen Receptor Modulators (SERMs) in this clinical scenario?
Show answer →In postmenopausal women, Aromatase Inhibitors (Exemestane or Anastrozole) are preferred when there is a high risk or history of thromboembolic events. SERMs (Tamoxifen/Raloxifene) carry a Black Box Warning for VTE and stroke. The MAP.3 and IBIS-II trials demonstrated that AIs significantly reduce the incidence of invasive breast cancer in high-risk postmenopausal women without increasing the risk of VTE or endometrial cancer. Clinical Pearl: While AIs avoid VTE risks, they increase the risk of bone loss (osteoporosis) and arthralgias, necessitating baseline and periodic DEXA scans.
In a three-generation pedigree, what symbol represents the proband and what does an arrow pointing to a shaded square indicate?
Show answer →The proband is the individual being evaluated or the first affected family member seeking medical attention. A shaded square represents an affected male; an arrow points to the proband. Exam Tip: ONCC emphasizes the ability to interpret pedigree symbols. Remember: Squares = males, circles = females, diamonds = gender unspecified, and a diagonal line through a symbol = deceased. Vertical lines connect parents to children, and horizontal lines denote a mating relationship.
According to 2026 ACS guidelines, at what age MUST a woman of average risk begin annual screening mammography, and what is the recommendation for women aged 40-44?
Show answer →ACS recommends annual mammograms starting at age 45. Women aged 40-44 should have the opportunity to begin annual screening if they choose. By age 55, women can transition to biennial screening or continue annual. NCCN differs by recommending annual screening starting at age 40 for average risk. Exam Tip: ONCC often tests the choice period (40-44) vs the mandatory start age (45) per ACS. Distinguish between these two organizations' starting ages.
A patient with a suspicious breast mass undergoes a core needle biopsy rather than a fine-needle aspiration (FNA). What is the primary clinical advantage of a core needle biopsy in this oncology setting?
Show answer →Core needle biopsies provide intact tissue architecture (histology), whereas FNA only provides individual cells (cytology). Histology is essential for determining tumor grade, invasiveness (ductal carcinoma in situ vs. invasive), and performing immunohistochemistry (IHC) for biomarkers like HER2 and ER/PR. Exam Strategy: The ONCC often tests the why behind procedure selection. Remember: Core = Architecture/Grade; FNA = Presence of malignancy only.
A patient receives 5-Fluorouracil (5-FU). During which phase of the cell cycle does this antimetabolite exert its primary cytotoxic effect, and what is the specific mechanism?
Show answer →5-FU is an S-phase specific antimetabolite. It acts as a pyrimidine analog that inhibits thymidylate synthase, preventing the synthesis of thymidine, which is essential for DNA replication. Because it is phase-specific, it is most effective during active DNA synthesis. Exam Strategy: ONCC often tests the timing of antimetabolites. Remember that S-phase agents are frequently administered via continuous infusion to maximize the number of cells caught during the vulnerable DNA synthesis window. Common distractors include G2 or M-phase mechanisms.
17–20 correct
Strong. Move to the hardest material and timed drilling rather than re-reading topics you already know.
12–16 correct
A normal mid-prep score. Work the topics you missed one at a time — the topic pages below are built for exactly that.
Under 12 correct
Early days. Go topic by topic instead of taking more mixed tests: pick your weakest area below and drill it until the questions feel routine.
Management questions
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Pathology questions
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Basics questions
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Pharmacology questions
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Assessment questions
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Diagnostics questions
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Procedures questions
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Try 30 free OCN cards firstIt is 20 real question-and-answer cards from our 1050-card OCN deck, mixed across topics so it feels like the breadth of the exam. It is not the official ONCC exam and is not endorsed by ONCC — for the official outline and any official practice material, go to ONCC directly.
Use the bands on this page as study guidance, not as a pass mark: we do not publish a passing score for the OCN because ONCC sets it, and it can change. Confirm the current standard in the official handbook.
No — deliberately. The 30 cards on the free OCN preview page and these 20 questions do not overlap, so you get 50 free questions across the two pages.
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Eligibility rules, fees, question counts and passing standards are set by the certifying body and change over time. Always confirm them at the source before you apply or schedule your exam — our flashcards are practice material, not the official handbook.