Oncological Surgery — MCQs

Oncological Surgery Indian Medical PG Practice Questions and MCQs

Question 151: What is the appropriate treatment for an incidentally detected appendicular carcinoid tumor measuring 2.5 cm?

A. Right hemicolectomy (Correct Answer)
B. Limited resection of the right colon
C. Total colectomy
D. Appendicectomy

Explanation: ***Right hemicolectomy*** - An appendiceal carcinoid tumor **larger than 2 cm** (or with **mesoappendix invasion, positive margins, or high-grade features**) warrants a right hemicolectomy due to a significantly higher risk of lymph node metastasis (20-30%). - This 2.5 cm tumor clearly exceeds the 2 cm threshold, making right hemicolectomy the standard of care. - This procedure ensures adequate oncological margins and removal of regional lymph nodes, which is crucial for complete treatment. *Limited resection of the right colon* - This option is insufficient for an appendiceal carcinoid of this size, as it may not remove all regional lymph nodes or provide adequate oncological margins. - Limited resection lacks the systematic lymphadenectomy required for tumors exceeding 2 cm. *Total colectomy* - This is an **overly aggressive** and unnecessary procedure for an isolated appendiceal carcinoid tumor, even one of this size. - Total colectomy is typically reserved for diffuse colonic involvement, multifocal tumors, or specific genetic syndromes, which is not indicated here. *Appendicectomy* - An appendicectomy alone is only appropriate for very small appendiceal carcinoid tumors, typically **less than 1 cm** in size, with negative margins and without evidence of mesoappendix invasion or aggressive features. - For a 2.5 cm tumor, the risk of regional lymph node involvement (20-30%) is too high for appendicectomy to be considered adequate oncological treatment.

Question 152: Type of hemicolectomy done for carcinoma of the appendix?

A. Right hemicolectomy (Correct Answer)
B. Extended Right hemicolectomy
C. Left hemicolectomy
D. Extended left hemicolectomy

Explanation: ***Right hemicolectomy*** - Carcinoma of the appendix typically requires a **right hemicolectomy** due to the **lymphatic drainage** patterns of the appendix which extend to the right colon mesentery. - This procedure ensures adequate removal of the primary tumor, regional lymph nodes, and a segment of the adjacent colon for oncological clearance. *Extended Right hemicolectomy* - This procedure involves removal of a larger segment of the colon (**right colon plus transverse colon**), which is usually not necessary for standard appendiceal carcinomas unless there's extensive local spread to the transverse colon or multiple metastatic lymph nodes in that region. - It is a more extensive operation with higher morbidity and is typically reserved for lesions involving the **hepatic flexure** or proximal transverse colon. *Left hemicolectomy* - A left hemicolectomy removes the **descending colon** and a portion of the transverse colon, which is surgically distant from the appendix. - This procedure is indicated for tumors of the **descending colon** or **splenic flexure**, and has no role in the treatment of appendiceal carcinoma. *Extended left hemicolectomy* - This operation involves removal of the **descending colon, sigmoid colon, and sometimes the distal transverse colon**, which is far removed from the appendix. - It is performed for carcinomas of the **distal transverse colon, splenic flexure, or descending colon**, and is inappropriate for appendiceal malignancies.

Question 153: What is the standard excision margin for thick melanomas (>2 mm Breslow thickness)?

A. 2 cm (Correct Answer)
B. 5 cm
C. 7 cm
D. 10 cm

Explanation: **2 cm** - For **thick melanomas** with a Breslow thickness greater than 2 mm, a **2 cm excision margin** is recommended to minimize local recurrence risk. - This margin ensures adequate removal of microscopic disease, balancing complete tumor excision with cosmetic and functional outcomes. *5 cm* - A **5 cm excision margin** is not standard for melanoma regardless of thickness and would result in excessive tissue removal. - Such large margins are generally reserved for very rare, extremely aggressive soft tissue sarcomas or other extensive skin malignancies. *7 cm* - A **7 cm excision margin** is significantly wider than current recommendations for any melanoma thickness. - This would lead to unnecessary morbidity, including large wound defects that might require complex reconstructive surgery. *10 cm* - A **10 cm excision margin** is exceptionally wide and not medically indicated for melanoma management. - Applying such a large margin would result in substantial tissue loss and functional impairment without offering additional survival benefit.

Question 154: Which metastases are most common to the thyroid?

A. Kidney (Correct Answer)
B. GIT
C. Lung
D. Breast

Explanation: ***Kidney (Renal Cell Carcinoma)*** - **Renal cell carcinoma** is the most common primary tumor to metastasize to the thyroid gland, accounting for approximately 30-50% of all thyroid metastases. - Thyroid metastases from renal cancer are often **hypervascular** and may present as rapidly growing thyroid nodules. - These metastases typically indicate advanced disease and occur in the setting of widespread metastatic involvement. *Lung* - **Lung cancer** is the second most common source of thyroid metastases, particularly small cell and non-small cell carcinoma. - Lung cancer metastases to the thyroid usually occur in patients with known disseminated disease. - These are often identified incidentally during imaging or at autopsy. *Breast* - **Breast cancer** is the third most common primary tumor to metastasize to the thyroid. - Lobular carcinoma of the breast shows a higher propensity for thyroid metastases compared to ductal carcinoma. - Presentation is typically in the context of widespread metastatic disease. *GIT* - **Gastrointestinal (GIT) cancers**, including colorectal and gastric cancers, are uncommon sources of thyroid metastases. - When present, GIT metastases to the thyroid signify advanced disease with multiple organ involvement. - These are rare and usually discovered incidentally during evaluation for other metastatic sites.

Question 155: Which of the following statements about meningiomas is true?

A. Approximately 5% of meningiomas are malignant.
B. Arise from the dural layer
C. Meningiomas are more common in women due to hormonal influences.
D. 95% cure rate following total surgical resection of benign meningiomas (Correct Answer)

Explanation: ***95% cure rate following treatment*** - Meningiomas generally have a **high cure rate of approximately 95%** following surgical resection, especially when they are completely excised [1]. - They are typically **benign tumors**, resulting in favorable outcomes with appropriate management [1]. *Arise from arachnoid layer* - Meningiomas actually arise from **meningothelial cells** of the **arachnoid layer**, but this statement does not fully explain their pathogenesis. - This mischaracterization does not provide an accurate understanding of the tumor's origin and biology. *50% are malignant* - Most meningiomas are benign; only a small percentage, about **1-5%**, are classified as malignant. - Thus, stating that **50% are malignant** significantly overestimates the incidence of aggressive forms. *More common in men* - Meningiomas are more prevalent in **women**, especially those aged between 30-70 years, with a female-to-male ratio of approximately **3:1**. - This option is incorrect as it misrepresents the demographic distribution of the disease. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1316-1317.

Question 156: The surgeon is exploring the mediastinum and finds a thymic mass invading the neighboring pericardium and phrenic nerves. Frozen section shows a thymoma (low-risk histology). What is the next intraoperative plan?

A. Complete resection of tumor (Correct Answer)
B. Abandon the surgery & start radiotherapy
C. Close the mediastinum and wait for final report
D. Abandon the surgery & start chemotherapy

Explanation: ***Complete resection of tumor*** - Even with invasion into neighboring structures like the **pericardium** and **phrenic nerves**, a **thymoma** should be completely resected to achieve the best possible outcome. - **Complete surgical resection (R0 resection)** remains the cornerstone of treatment for thymomas, even in locally invasive cases (Masaoka Stage III), as it offers the best prognosis and potential for cure. - The goal is to achieve **negative margins** while resecting involved structures (pericardium, phrenic nerve if necessary) to ensure complete tumor removal. *Abandon the surgery & start chemotherapy* - **Chemotherapy** is generally reserved for **thymic carcinomas**, unresectable thymomas, or as neoadjuvant therapy for borderline resectable cases, none of which apply here. - Abandoning surgery prematurely for a resectable thymoma, even with local invasion, would significantly compromise the patient's long-term outcome and chance for cure. *Abandon the surgery & start radiotherapy* - **Radiotherapy** is used adjunctively after incomplete resection (R1/R2) or for advanced **unresectable cases**, but a locally invasive thymoma that appears resectable should be managed with surgery first. - Abandoning the opportunity for **complete surgical removal** based on local invasion alone is not the standard approach, as Stage III thymomas are often resectable. *Close the mediastinum and wait for final report* - Waiting for the **final pathology report** significantly delays definitive treatment, and the frozen section result indicating **thymoma** provides sufficient information to proceed with resection if technically feasible. - This approach would necessitate a **second surgery**, posing unnecessary risks, increased morbidity, and discomfort to the patient, given that frozen section histology guides appropriate intraoperative management.

Question 157: Treatment of squamous cell carcinoma of the anal canal not involving the deeper structures includes

A. Abdominoperineal resection
B. Wide local excision with radiotherapy
C. Wide local excision with chemoradiation
D. Chemoradiation (Correct Answer)

Explanation: ***Chemoradiation*** - **Chemoradiation** is the gold standard for treating **squamous cell carcinoma of the anal canal** that does not involve deeper structures, aiming for organ preservation. - This combined modality achieves high rates of tumor control and anus preservation, avoiding the need for a permanent colostomy. *Abdominoperineal resection* - **Abdominoperineal resection (APR)** is a more invasive surgical procedure involving the removal of the rectum and anus, resulting in a **permanent colostomy**. - It is typically reserved for **recurrent disease**, treatment failures, or large, deeply invasive tumors that cannot be managed with chemoradiation. *Wide local excision with radiotherapy* - While **wide local excision** can be used for very superficial or small, well-differentiated tumors, adding **radiotherapy alone** is generally insufficient for squamous cell carcinoma of the anal canal. - The combination of chemotherapy with radiation significantly improves treatment outcomes by increasing radiosensitization and targeting microscopic disease. *Wide local excision with chemoradiation* - **Wide local excision** followed by **chemoradiation** is generally not the primary approach for most anal canal SCCs not involving deeper structures. - The standard treatment is definitive chemoradiation alone, reserving surgery for biopsy or salvage.

Question 158: The most common tumor in the posterior mediastinum is:

A. Schwannoma (Correct Answer)
B. Lymphoma
C. Teratoma
D. Bronchogenic cyst

Explanation: ***Schwannoma*** - **Schwannomas** are **neurogenic tumors** that arise from the **nerve sheaths** and are the most common type of tumor found in the **posterior mediastinum**. - They account for about **20% of all mediastinal tumors** and usually present as a solitary, well-defined mass. *Lymphoma* - Lymphomas are more commonly found in the **anterior** or **middle mediastinum**, often presenting as multiple enlarged lymph nodes. - While they can occur in the posterior mediastinum, they are **not the most common primary tumor type** in this location. *Teratoma* - **Teratomas** are **germ cell tumors** and are predominantly found in the **anterior mediastinum**. - They contain tissue from all three germ layers and can be benign or malignant, often presenting with calcifications or fat. *Bronchogenic cyst* - **Bronchogenic cysts** are **congenital cysts** derived from abnormal budding of the tracheobronchial tree, usually located in the **middle mediastinum** or intraparenchymally. - While they can occasionally be found in the posterior mediastinum, they are developmental anomalies rather than primary tumor types and are less common than neurogenic tumors.

Practice by Chapter

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