Oncological Surgery — MCQs

Oncological Surgery Indian Medical PG Practice Questions and MCQs

Question 71: Gastrointestinal stromal tumors (GIST) are most common in which part of the gastrointestinal tract?

A. Stomach (Correct Answer)
B. Duodenum
C. Ileum
D. Rectum

Explanation: **Explanation:** Gastrointestinal Stromal Tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. They originate from the **Interstitial Cells of Cajal (ICC)**, which are the pacemaker cells located in the muscularis propria responsible for gut motility. **Why Stomach is Correct:** The **stomach** is the most frequent site of occurrence, accounting for approximately **60-70%** of all GIST cases. Most gastric GISTs are incidentally discovered and carry a better prognosis compared to those found in the small or large intestine. **Analysis of Incorrect Options:** * **Small Intestine (Duodenum/Ileum):** The small intestine is the second most common site, accounting for about **20-30%** of cases. While GISTs can occur in the duodenum or ileum, they are significantly less frequent than gastric primary tumors. * **Rectum:** The rectum and esophagus are rare sites, each accounting for less than **5%** of GIST cases. **High-Yield Clinical Pearls for NEET-PG:** * **Molecular Marker:** Approximately 95% of GISTs are positive for **CD117 (c-KIT)**, a tyrosine kinase receptor. **DOG1** (Discovered on GIST-1) is another highly sensitive marker. * **Genetic Mutation:** Most cases involve a mutation in the **c-KIT gene**; a subset involves the **PDGFRA** mutation. * **Treatment:** The gold standard for localized GIST is **complete surgical resection** (R0) with clear margins. Lymphadenectomy is usually not required as GISTs rarely spread via lymphatics. * **Targeted Therapy:** **Imatinib mesylate** (a tyrosine kinase inhibitor) is the drug of choice for metastatic, unresectable, or high-risk recurrent GISTs.

Question 72: Symptoms from a retroperitoneal sarcoma are usually produced by which of the following mechanisms?

A. Bleeding into the tumor mass
B. Compression of adjacent tissues (Correct Answer)
C. Invasion of retroperitoneal organs
D. Metastases to retroperitoneal lymph nodes

Explanation: **Explanation:** **Why Option B is Correct:** Retroperitoneal sarcomas (RPS) are typically slow-growing tumors that arise in the expansive, compliant space of the retroperitoneum. Because this space can accommodate significant growth before vital structures are compromised, these tumors often reach a massive size (frequently >10 cm) before becoming symptomatic. The most common clinical presentation is a **vague abdominal pain or a palpable mass** caused by the **compression and displacement** of adjacent organs (such as the kidneys, ureters, or bowel) rather than direct invasion. **Why Other Options are Incorrect:** * **Option A:** While spontaneous hemorrhage into a large sarcoma can occur, it is a rare complication and not the usual mechanism for initial symptom production. * **Option C:** Although sarcomas can be locally aggressive, they characteristically tend to **push and displace** adjacent organs rather than invade them early in the disease course. This "pseudocapsule" often makes surgical planes identifiable, though true invasion can occur in high-grade variants. * **Option D:** Sarcomas are mesenchymal tumors that characteristically spread via the **hematogenous route** (most commonly to the lungs). Lymph node metastasis is rare (seen in <5% of cases), unlike carcinomas. **NEET-PG High-Yield Pearls:** * **Most common histological type:** Liposarcoma (specifically well-differentiated or dedifferentiated), followed by Leiomyosarcoma. * **Gold Standard Investigation:** Contrast-Enhanced CT (CECT) of the abdomen and pelvis. * **Biopsy Protocol:** If required, a **Core Needle Biopsy** (percutaneous) is preferred. Avoid transperitoneal biopsy to prevent tumor seeding. * **Treatment of Choice:** Radical surgical resection with negative margins (R0 resection). This often requires en-bloc resection of adjacent organs (e.g., kidney or colon) even if not directly invaded.

Question 73: A patient has a 3 cm mass over the lower lip and a single lymph node measuring 3 cm was present on the contralateral side. What is the TNM staging of this lip carcinoma?

A. T1 N2a
B. T2 N2b
C. T2 N2c (Correct Answer)
D. T1 N2b

Explanation: ### **Explanation** The staging of Lip and Oral Cavity Carcinoma follows the AJCC (8th Edition) TNM classification. **1. T-Staging (Tumor Size):** * **T1:** Tumor ≤ 2 cm in greatest dimension. * **T2:** Tumor > 2 cm but ≤ 4 cm. * **T3:** Tumor > 4 cm. * In this case, the mass is **3 cm**, which classifies it as **T2**. **2. N-Staging (Nodal Involvement):** * **N1:** Single ipsilateral node ≤ 3 cm. * **N2a:** Single ipsilateral node > 3 cm but ≤ 6 cm. * **N2b:** Multiple ipsilateral nodes, none > 6 cm. * **N2c:** Bilateral or **contralateral** lymph nodes, none > 6 cm. * Since the patient has a **single 3 cm node on the contralateral side**, it is classified as **N2c**. Combining these gives the stage **T2 N2c**. --- ### **Why Incorrect Options are Wrong:** * **Option A (T1 N2a):** Incorrect because the tumor is > 2 cm (T2) and the node is contralateral (N2c), not ipsilateral (N2a). * **Option B (T2 N2b):** While the T-stage is correct, N2b refers to multiple ipsilateral nodes. Contralateral involvement automatically upgrades the N-stage to N2c. * **Option D (T1 N2b):** Incorrect on both counts; the size is T2 and the nodal distribution is N2c. --- ### **High-Yield Clinical Pearls for NEET-PG:** * **Most Common Site:** The lower lip is the most common site for lip cancer (usually Squamous Cell Carcinoma) due to sun exposure. * **Prognosis:** Lip cancer has a better prognosis than intraoral SCC because it is detected earlier. * **AJCC 8th Ed. Update:** For oral cavity (not lip), **Depth of Invasion (DOI)** is now a critical component of T-staging (T1 ≤ 5mm, T2 > 5mm to 10mm, T3 > 10mm). * **N-Stage Note:** Any node > 6 cm is classified as **N3**. Presence of **Extranodal Extension (ENE)** significantly upgrades the N-stage in the 8th edition.

Question 74: Which is an important chemotherapy agent used for thymoma treatment?

A. Cisplatin (Correct Answer)
B. 5-FU
C. Doxorubicin
D. Methotrexate

Explanation: **Explanation:** Thymomas are rare epithelial tumors of the thymus gland. While surgical resection (thymectomy) is the primary treatment for early-stage disease, chemotherapy is indicated for advanced, metastatic, or unresectable cases. **1. Why Cisplatin is the Correct Answer:** **Cisplatin** is considered the most active and essential single agent in the treatment of thymic epithelial tumors. It forms the backbone of standard combination chemotherapy regimens, such as **PAC** (Cisplatin, Adriamycin/Doxorubicin, and Cyclophosphamide) or **ADOC** (Cisplatin, Doxorubicin, Vincristine, and Cyclophosphamide). These platinum-based regimens are preferred because they demonstrate high objective response rates, which can often downstage a tumor for subsequent surgical resection. **2. Analysis of Incorrect Options:** * **5-FU (5-Fluorouracil):** Primarily used for gastrointestinal, breast, and head and neck cancers. It is not a first-line agent for thymoma. * **Doxorubicin:** While Doxorubicin is frequently used *in combination* with Cisplatin for thymoma (as part of the PAC regimen), **Cisplatin** is statistically the more potent and "important" anchor drug in these protocols. * **Methotrexate:** An antimetabolite used in leukemias, lymphomas, and osteosarcomas; it has no established role in the standard management of thymoma. **Clinical Pearls for NEET-PG:** * **Most common association:** Myasthenia Gravis (seen in 30-45% of thymoma patients). * **Staging System:** The **Masaoka-Koga staging system** is the most widely used for thymoma. * **Gold Standard Treatment:** Complete surgical excision (Total Thymectomy). * **High-Yield Fact:** If a patient has Myasthenia Gravis, always screen for thymoma via CT chest; conversely, if a thymoma is found, evaluate for Myasthenia Gravis.

Question 75: Kaposi sarcoma is caused by which human herpesvirus?

A. HHV 17
B. HHV 8 (Correct Answer)
C. HPV 16
D. Human simian virus 40

Explanation: **Explanation:** **Correct Answer: B. HHV 8** Kaposi Sarcoma (KS) is a multicentric angioproliferative tumor of the vascular endothelium. It is definitively caused by **Human Herpesvirus 8 (HHV-8)**, also known as Kaposi Sarcoma-associated Herpesvirus (KSHV). The virus induces oncogenesis by expressing viral homologs of cellular genes (like cyclin D and IL-6), leading to uncontrolled proliferation of spindle cells and neoangiogenesis. **Analysis of Incorrect Options:** * **A. HHV 17:** This is a distractor; there is no recognized human herpesvirus numbered 17. There are only 8 known human herpesviruses. * **C. HPV 16:** Human Papillomavirus type 16 is a high-risk DNA virus strongly associated with squamous cell carcinomas, specifically **Cervical Cancer** and oropharyngeal cancers, but not Kaposi Sarcoma. * **D. Human simian virus 40 (SV40):** While SV40 is a polyomavirus known to cause tumors in laboratory animals and has been linked to human mesotheliomas and brain tumors in some studies, it is not the causative agent of Kaposi Sarcoma. **High-Yield Clinical Pearls for NEET-PG:** * **Four Clinical Variants:** 1. Classic (older Mediterranean men), 2. Endemic (African), 3. Iatrogenic (transplant-related), and 4. AIDS-associated (most common and aggressive). * **Histology:** Characterized by **spindle-shaped cells**, slit-like vascular spaces, and extravasated RBCs. * **Clinical Presentation:** Presents as purple, red, or brown cutaneous nodules or plaques, often on the lower extremities or oral mucosa. * **Treatment:** Highly Active Antiretroviral Therapy (HAART) is the mainstay for AIDS-associated KS; localized lesions may be treated with intralesional vinblastine or radiotherapy.

Question 76: What is the stage of a squamous cell carcinoma classified as T3N2M0?

A. Stage I
B. Stage II
C. Stage III (Correct Answer)
D. Stage IV

Explanation: ### Explanation The staging of squamous cell carcinoma (SCC), particularly in the head and neck or skin, follows the **AJCC TNM Staging System**. Staging is determined by the combination of the primary tumor size (**T**), regional lymph node involvement (**N**), and distant metastasis (**M**). **1. Why Stage III is Correct:** In the standard TNM staging for most solid tumors (including SCC of the head and neck), **Stage III** typically represents advanced local disease or regional nodal involvement without distant metastasis. Specifically: * **T3** denotes a large primary tumor (e.g., >4 cm or with deep invasion). * **N2** indicates significant regional lymph node involvement (multiple nodes, large size, or bilateral). * **M0** confirms the absence of distant metastasis. The presence of N2 nodal disease automatically elevates the classification to at least Stage III or IV depending on the specific sub-site, but T3N2M0 is classically categorized as **Stage III** (or Stage IVA in some specific head and neck sites, though Stage III remains the most common general answer for T3/N2 combinations in standard surgical exams). **2. Why Other Options are Wrong:** * **Stage I (T1N0M0):** Represents a small, localized tumor with no nodal involvement. * **Stage II (T2N0M0):** Represents a larger localized tumor but still without nodal involvement. * **Stage IV:** Usually reserved for T4 (very advanced local invasion), N3 (massive nodal disease), or any **M1** (distant metastasis). **Clinical Pearls for NEET-PG:** * **M1 always equals Stage IV**, regardless of T or N status. * **Nodal involvement (N1 or higher)** generally moves a patient out of Stage I or II. * For SCC of the skin, a diameter **>2 cm** or invasion into deep structures (bone/muscle) are high-risk features that upgrade the T-stage. * The most important prognostic factor for SCC of the head and neck is the **status of cervical lymph nodes**.

Question 77: What is the most common primary site for a metastatic bone tumor in males?

A. Lung (Correct Answer)
B. Liver
C. Prostate
D. Kidney

Explanation: **Explanation:** The correct answer is **Lung (Option A)**. In clinical practice, while prostate cancer is highly osteophilic (bone-seeking), **lung cancer** is statistically the most common primary malignancy to metastasize to the bone in males. This is due to the high overall incidence of lung cancer and its aggressive hematogenous spread. **Analysis of Options:** * **Lung (Correct):** It is the most common primary source of bone metastasis in men. These lesions are typically **osteolytic** (bone-destroying) and often present with pathological fractures. * **Prostate (Incorrect):** While prostate cancer is the second most common cause and is famous for producing **osteoblastic** (bone-forming) lesions, it ranks behind lung cancer in total metastatic frequency. * **Liver (Incorrect):** Hepatocellular carcinoma (HCC) rarely metastasizes to the bone; it more commonly spreads intrahepatically or to the lungs. * **Kidney (Incorrect):** Renal Cell Carcinoma (RCC) is a frequent cause of bone metastasis (characteristically "blow-out" lytic lesions), but it is less common than lung or prostate primaries. **NEET-PG High-Yield Pearls:** * **Overall (Both Sexes):** Breast cancer is the most common cause of bone metastasis. * **In Females:** Breast > Lung > Thyroid > Kidney. * **In Males:** Lung > Prostate > Kidney > Thyroid. * **Type of Lesion:** * **Pure Osteoblastic:** Prostate, Carcinoid. * **Pure Osteolytic:** RCC, Thyroid, Lung (usually), Multiple Myeloma. * **Mixed:** Breast (most common mixed). * **Commonest Site of Bone Metastasis:** Spine (specifically the thoracic spine) is the most common site, followed by the pelvis and femur.

Question 78: What is the commonest surgical procedure for soft tissue sarcoma?

A. Marginal excision
B. Enucleation
C. Wide local excision
D. Compartmental excision (Correct Answer)

Explanation: **Explanation:** The management of soft tissue sarcomas (STS) is a high-yield topic for NEET-PG, focusing on the principle of achieving negative margins to prevent local recurrence. **Why Compartmental Excision is the Correct Answer:** Soft tissue sarcomas typically grow along anatomical planes and are contained within a specific muscle compartment. **Compartmental excision** involves the removal of the entire anatomical compartment (including the tumor, its pseudocapsule, and the entire muscle group from origin to insertion). This is considered the "gold standard" surgical procedure because it ensures the widest possible margin, effectively addressing the "skip lesions" that often occur within the same compartment. **Analysis of Incorrect Options:** * **Marginal Excision (A):** The incision is made through the pseudocapsule of the tumor. This leaves behind microscopic disease and has an unacceptably high recurrence rate (up to 80%). * **Enucleation (B):** This involves "shelling out" the tumor. Since sarcomas have a false capsule (pseudocapsule) formed by compressed cancer cells, enucleation inevitably leaves tumor cells in the wound bed. * **Wide Local Excision (C):** This involves removing the tumor with a 1–2 cm margin of healthy tissue. While commonly used for many tumors, in the context of STS, it is often less definitive than a full compartmental resection unless combined with radiotherapy. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Lower limb (specifically the thigh). * **Most common histological type:** Undifferentiated Pleomorphic Sarcoma (formerly Malignant Fibrous Histiocytoma). * **Route of Spread:** Primarily hematogenous (to lungs). **Exception:** Epithelioid sarcoma, Clear cell sarcoma, and Angiosarcoma often spread to lymph nodes. * **Biopsy Gold Standard:** Core needle biopsy (incisional biopsy is reserved for large tumors where core biopsy is inconclusive).

Question 79: All of the following are true regarding Kaposi sarcoma except:

A. Predominant in males
B. Multicentric origin
C. Chemotherapy is the treatment of choice
D. Occurs in AIDS patients only (Correct Answer)

Explanation: **Explanation:** Kaposi Sarcoma (KS) is a low-grade vascular tumor associated with **Human Herpesvirus 8 (HHV-8)**. The statement that it occurs "only" in AIDS patients is incorrect, making it the right answer for this "except" question. **1. Why Option D is the Correct Answer:** While KS is the most common neoplasm in AIDS patients (AIDS-defining illness), it is not exclusive to them. There are four distinct clinical variants: * **Classic (Sporadic):** Affects elderly men of Mediterranean/Eastern European descent. * **Endemic (African):** Occurs in HIV-negative children and adults in Equatorial Africa. * **Iatrogenic (Transplant-related):** Seen in patients on chronic immunosuppression. * **Epidemic (AIDS-associated):** The most aggressive form. **2. Analysis of Incorrect Options:** * **Option A (Predominant in males):** True. All forms of KS show a strong male predilection (e.g., the Classic form has a male-to-female ratio of up to 15:1). * **Option B (Multicentric origin):** True. KS is not a single primary tumor that metastasizes; rather, it arises from the multifocal proliferation of endothelial cells in various sites (skin, lymph nodes, viscera) simultaneously. * **Option C (Chemotherapy is the treatment of choice):** True for disseminated or symptomatic disease. While localized lesions can be treated with radiotherapy or cryotherapy, systemic chemotherapy (e.g., Liposomal Doxorubicin or Paclitaxel) is the mainstay for extensive visceral involvement. **Clinical Pearls for NEET-PG:** * **Histology:** Characterized by **spindle cells**, slit-like vascular spaces, and extravasated RBCs. * **Initial Management in AIDS:** Highly Active Antiretroviral Therapy (HAART) often leads to regression of lesions. * **Appearance:** Typically presents as non-blanching, purple/brown macules, plaques, or nodules.

Question 80: A 35-year-old female is diagnosed with ductal carcinoma in situ of the breast. What is the best possible management?

A. Breast-conservative surgery (Correct Answer)
B. Simple mastectomy
C. Modified radical mastectomy
D. Radical mastectomy

Explanation: ### Explanation **Correct Option: A. Breast-conservative surgery (BCS)** **Concept:** Ductal Carcinoma in Situ (DCIS) is a non-invasive, pre-malignant condition where malignant cells are confined within the basement membrane of the breast ducts. Since there is no invasion into the stroma, the risk of axillary lymph node metastasis is extremely low (<1%). The primary goal of treatment is to prevent progression to invasive carcinoma while preserving quality of life. **Breast-conservative surgery (Lumpectomy/Wide Local Excision)** with a clear margin (typically 2 mm) followed by radiotherapy is the standard of care. It offers equivalent survival rates to mastectomy with superior cosmetic outcomes. **Why other options are incorrect:** * **B. Simple Mastectomy:** While effective, it is considered "over-treatment" for most localized DCIS. It is reserved only for cases with multicentric disease, large tumor-to-breast ratio, or contraindications to radiotherapy. * **C. Modified Radical Mastectomy (MRM):** This involves removing the breast and axillary lymph nodes. Since DCIS is non-invasive, routine axillary dissection is unnecessary and leads to avoidable morbidity (e.g., lymphedema). * **D. Radical Mastectomy:** This historical procedure (removing breast, pectoralis muscles, and nodes) is obsolete for DCIS and almost all modern breast cancers. **High-Yield Clinical Pearls for NEET-PG:** 1. **Van Nuys Prognostic Index (VNPI):** Used to determine the risk of recurrence in DCIS and decide between excision alone, excision + radiation, or mastectomy. 2. **Axillary Management:** Sentinel Lymph Node Biopsy (SLNB) is NOT routine for DCIS but may be considered if a mastectomy is planned (as a later SLNB is impossible once the breast is removed). 3. **Microcalcifications:** DCIS most commonly presents as suspicious pleomorphic microcalcifications on screening mammography. 4. **Tamoxifen:** Often added post-surgery for ER-positive DCIS to reduce the risk of ipsilateral recurrence and contralateral new primary cancer.

Practice by Chapter

Principles of Surgical Oncology

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Cancer Staging

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Surgical Margins in Cancer Surgery

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Sentinel Lymph Node Concepts

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Neoadjuvant and Adjuvant Therapy

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Metastasectomy

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Cytoreductive Surgery

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Hyperthermic Intraperitoneal Chemotherapy

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Palliative Surgical Procedures

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Minimally Invasive Approaches in Cancer Surgery

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Follow-up and Surveillance

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Hereditary Cancer Syndromes

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