US Board Certification
The ABS-CGSO is the definitive American board certification for surgical oncologists. This guide covers what the exam is, how it is structured, who qualifies, and what to study — with an emphasis on what separates candidates who pass from those who do not.
ABS-CGSO stands for American Board of Surgery — Complex General Surgical Oncology. It is a Certificate of Added Qualifications (CAQ) issued by the American Board of Surgery (ABS) to surgeons who have completed an accredited fellowship in surgical oncology and passed a rigorous qualifying examination.
The CGSO certification was created in recognition that surgical oncology, as a subspecialty, requires depth of knowledge and technical skill that exceeds the scope of general surgery training. It serves as the definitive credential for surgical oncologists practising in the United States, providing recognition by hospitals, academic institutions, insurance systems, and professional organizations.
The ABS administers the CGSO exam in partnership with the Society of Surgical Oncology (SSO), which maintains the accreditation standards for surgical oncology fellowships and contributes to the development of the examination content blueprint. Achieving CGSO certification signals mastery across the full breadth of surgical oncology — from melanoma and breast cancer through hepatopancreatobiliary surgery and peritoneal surface malignancy.
The ABS-CGSO is a computer-based written examination consisting of approximately 250 questions in a single-best-answer format. There is no oral component.
Examination Specifications
Unlike some subspecialty boards, the ABS-CGSO does not include a separate oral or practical component. The written examination is comprehensive and tests both factual recall and clinical reasoning — questions frequently present patient vignettes requiring the candidate to select the most appropriate next step, the correct operation, or the best evidence-based management strategy.
CGSO eligibility is strictly defined by the ABS. Candidates must meet all of the following criteria:
International medical graduates who hold ABS General Surgery certification and have completed an SSO-accredited fellowship are eligible to sit the CGSO examination. Candidates should confirm current requirements with the ABS directly, as eligibility criteria and application windows are subject to periodic revision.
The ABS CGSO examination covers the full spectrum of surgical oncology. The content blueprint, updated periodically by the ABS, distributes questions across the following principal domains:
Melanoma and Skin Cancers
Melanoma staging and surgery, SLN biopsy, wide local excision margins, MCC, squamous and basal cell carcinoma of surgical significance.
Breast Cancer
Breast-conserving surgery, mastectomy types, axillary management, sentinel node biopsy, neoadjuvant therapy indications.
Endocrine Tumors
Thyroid cancer surgery, parathyroid disease, adrenal incidentaloma and malignancy, NETs, MEN syndromes.
Colorectal Cancer
Colon and rectal cancer surgery, TME, CME, laparoscopic and robotic approaches, local recurrence, rectal preservation.
Hepatopancreatobiliary
Hepatectomy for HCC and CRLM, pancreaticoduodenectomy, distal pancreatectomy, cholangiocarcinoma, gallbladder cancer.
Soft Tissue Sarcoma
Retroperitoneal and extremity sarcoma, compartmental resection, GIST management, margin principles, the role of radiation.
Peritoneal Surface Malignancy
CRS and HIPEC for appendiceal tumors, colorectal peritoneal metastases, mesothelioma — indications, completeness of cytoreduction.
Gastric and Esophageal Cancer
Total gastrectomy, subtotal gastrectomy, Ivor Lewis and minimally invasive esophagectomy, D2 lymphadenectomy, multimodal treatment.
ABS-CGSO questions are written to reflect evidence-based practice as defined by authoritative North American guidelines and consensus documents. The primary references candidates must master are:
The ABS-CGSO examination is administered annually. The application window typically opens in the spring, with examination sitting in the autumn. Exact dates and application deadlines are published on the ABS website at least six months in advance.
The CGSO certification requires ongoing maintenance through Maintenance of Certification (MOC), which includes continuing medical education, practice quality improvement, and periodic written assessment. Surgeons who obtained initial certification should confirm their MOC obligations with the ABS.
In the United States, ABS-CGSO certification is the universally recognized credential for surgical oncologists seeking academic appointments, leadership positions in cancer centres, and recognition as subspecialty experts by hospital privileging committees. Many NCI-designated cancer centres and academic medical centres give preference or require CGSO certification for surgical oncology faculty positions.
Beyond career recognition, the CGSO examination enforces currency. The breadth of the blueprint — from melanoma through peritoneal surface malignancy — demands that candidates remain current across NCCN guidelines, landmark trials, and evolving technical standards simultaneously. Candidates who approach examination preparation systematically emerge with a more rigorous, evidence-anchored approach to clinical practice.
For trainees completing SSO fellowships, sitting the CGSO exam during or immediately after fellowship is strongly recommended, when guideline knowledge is freshest and case experience is most recent.
SurgBoardsQ&A contains 5,278 questions mapped to the ABS-CGSO content blueprint, organized by tumor type and domain. Every question includes:
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50 questions free, no credit card required. Filter by board, tumor type, or difficulty. Explanations cite the NCCN guideline version and category letter.
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