SPARROW Study: Surgical Outcomes in Splenic Flexure Cancer

Colonic cancers located at the splenic flexure where the transverse colon turns into the descending colon are uncommon and represent less than 10% of all colorectal cancers. Because of their unique location between the blood supply of the right and left colon, there is no clear agreement on which surgical method provides the best results.

Two main procedures are used:

Segmental hemicolectomy, which removes only the part of the colon containing the tumor, and

Extended hemicolectomy, which removes a larger section of the colon and more lymph nodes.

The SPARROW Study is a prospective, multicenter observational study designed to compare these two surgical approaches in patients with splenic flexure cancer. The study will include about 140 patients (70 in each group) from multiple tertiary colorectal centers in Turkey and Europe.

Researchers will collect information about each patient's surgery, recovery, and follow-up outcomes. The main outcomes include postoperative ileus, leakage at the surgical connection (anastomosis), wound infection, and total postoperative complications. Other outcomes include number of lymph nodes removed, complete tumor resection (R0), hospital stay, recovery time, reoperation, and 3-year overall and disease-free survival.

By analyzing both short- and long-term results, the SPARROW Study aims to provide high-quality evidence to guide surgeons in choosing the best and safest operation for patients with splenic flexure cancers.

All participants will provide written informed consent before joining the study. The study has received ethical approval from the Koç University Ethics Committee and will be conducted in accordance with the Declaration of Helsinki.

Study Rationale:

Splenic flexure cancers pose unique surgical challenges due to their variable blood supply and lymphatic drainage. The optimal extent of resection remains controversial, with both extended right and left colectomy approaches showing different technical advantages. However, there are no prospective multicenter data comparing their perioperative and oncologic outcomes.

Study Design:

This is a prospective, multicenter observational cohort study involving tertiary colorectal cancer centers. The study will enroll 140 consecutive adult patients (≥18 years old) undergoing elective curative resection for histologically confirmed splenic flexure adenocarcinoma. Surgical approach-segmental or extended colectomy-will be chosen according to the operating surgeon's routine practice and preference, not assigned by randomization.

Primary Outcomes:

Postoperative ileus (incidence and duration)

Anastomotic leakage

Wound infection

Total postoperative complications

Secondary Outcomes:

Lymph node yield and R0 resection rate

Postoperative mortality

Operation time and estimated blood loss

Hospital stay, return to regular diet, and time to first flatus

Reoperation rates

3-year overall survival (OS) and disease-free survival (DFS)

Timeline:

Study start: 2025

Enrollment period: 24 months

Follow-up: 36 months per patient

Total duration: approximately 5 years

Ethical Conduct:

Ethical approval was obtained from the Koç University Ethics Committee. Each participating center will obtain local ethics approval. The study adheres to the principles of the Declaration of Helsinki and Good Clinical Practice (GCP).

Expected Impact:

This will be the first prospective multicenter observational study to compare segmental and extended hemicolectomy for splenic flexure cancers. The results will help standardize surgical decision-making and improve patient outcomes for this uncommon and technically challenging tumor location.

Inclusion Criteria:

• Adult patients aged 18 years or older
• Histologically confirmed adenocarcinoma of the splenic flexure
• Elective surgical resection performed with curative intent (segmental colectomy or extended hemicolectomy)
• Availability of complete perioperative and follow-up data
• Written informed consent provided prior to participation
• Surgery performed by colorectal or general surgeons meeting institutional eligibility criteria (≥20 colorectal cancer cases/year, ≥2 years of colorectal training)

Exclusion Criteria:

• Emergency surgery for obstruction, perforation, or bleeding
• Non-adenocarcinoma histology (e.g., lymphoma, neuroendocrine tumor, gastrointestinal stromal tumor)
• Patients undergoing palliative resections, local excisions, or bypass procedures without curative intent
• Presence of synchronous colorectal malignancy or distant metastasis requiring simultaneous resection
• Previous colorectal resection involving the splenic flexure
• Patients with incomplete clinical or pathological data or those lost to follow-up before 30 days postoperatively

This study will include adult patients diagnosed with splenic flexure adenocarcinoma who undergo elective curative resection (segmental or extended hemicolectomy) at participating tertiary colorectal surgery centers in Turkey and Europe. All patients will be treated according to the surgeon's standard practice and institutional protocols. Data will be collected prospectively for both perioperative and follow-up outcomes as part of the multicenter SPARROW Study.

De-identified individual participant data (IPD) underlying the published results will be shared, including baseline demographic information, surgical approach (segmental vs. extended hemicolectomy), operative characteristics, short-term perioperative outcomes, and follow-up survival data. No directly identifiable information (such as names, contact details, or institutional identifiers) will be included. Data will be available in a secure, de-identified format for qualified researchers upon reasonable request to the SPARROW Study Steering Committee through the Turkish Society of Colon and Rectal Surgery (TKRCD), following approval of a data-use agreement and ethical review.

De-identified individual participant data (IPD) and supporting materials will be available beginning 12 months after publication of the primary manuscript and will remain available indefinitely for qualified researchers upon reasonable request.

Qualified researchers affiliated with academic institutions, professional societies, or healthcare organizations may request access to the de-identified dataset, study protocol, statistical analysis plan, and informed consent form. Requests should be submitted in writing to the SPARROW Study Steering Committee via the Turkish Society of Colon and Rectal Surgery (TKRCD). Access will be granted after approval of the research proposal and signing of a data-use agreement ensuring ethical conduct, confidentiality, and non-commercial use. Data will be shared electronically through a secure, password-protected institutional platform.