Appendectomy at Gynecologic Surgery: Feasibility and Outcomes in a High Risk Gynecologic Population—Revealing a High Rate of Incidental Appendiceal Cancer

Introduction

The rate of primary appendiceal malignancy is 0.5% of all intestinal cancers. This kind of malignancy is a rare tumor not independently reported in the annual American Cancer Society's Cancer Facts and Statistics publication. Each year, 600–1000 cases are identified in the United States.

Appendicitis, as a separate entity, occurs in 7%–9% of the population. ¹ Sixteen million cases of appendicitis occurred globally in 2013, and there were 72,000 deaths directly attributed to this condition. ² In the United States, 300,000 patients are diagnosed with appendicitis annually and proceed to surgery. ³ Surgical management has been laparoscopic appendectomy at the time of diagnosis. Alternative management is antibiotic therapy, starting in the emergency room with intravenous therapy and continuing at home with oral therapy; but that is not the standard of care at this time. For patients treated with antibiotics, 20% end up with surgical management within the ensuing year.^4,5 Progressive appendicitis can lead to perforation, necessitating hospital admission for percutaneous drainage followed by surgery after the acute inflammatory response has resolved. Pathologic reviews of specimens removed due to diagnosis of appendicitis have shown documented obstructing tumors causing infection and perforation in 0.5%–1% of cases.^6,7 There is the inherent risk of pathologic misdiagnosis with medical management alone. ⁸

Prophylactic appendectomy at the time of concordant abdominal/pelvic surgery is a means of risk reduction for patients with the above medical diagnosis. Removal of the appendix would then decrease the 7%–9% lifetime risk of appendicitis, moving the risk to 0%. Minimal additional surgical risk occurs, as the procedure is done at the same time as another surgery.

Performing an appendectomy at the time of other abdominal–pelvic surgery may pick up an incidental synchronous tumor, increase the rate of diagnosis of primary appendiceal tumor, and possibly affect stage migration of gastrointestinal cancers in surgical patients.

In patients with gynecologic cancer, appendectomy has been noted to increase the rate of optimal debulking by removing tumor deposits on the appendix in bulky advanced disease, and appropriately surgically staging patients with microscopic disease spread to this site. ⁹ Appendectomy performed at the time of gynecologic cancer surgery can then also mitigate subsequent infectious risks in immunocompromised patients. Neutropenia in a patient receiving chemotherapy can put that patient at a higher risk of infection, including diverticulitis and appendicitis. Radiation therapy targets high dose X-rays to pelvic structures, including the right lower quadrant, causing inflammation and bowel complications to sometimes include colitis, enteritis, appendicitis, and obstruction from endarteritis. Removal of the appendix in this patient population may decrease these bowel complications. In the event of right lower-quadrant pain during adjuvant therapies, prior appendectomy then excludes appendicitis from the differential diagnosis.

This review was performed to evaluate the feasibility, safety, and outcomes of appendectomy done at the time of surgical intervention in a gynecologic, single-provider, high-risk subspeciality practice. Rates of appendectomy, the number of secondary malignancies encountered, factors contributing to feasibility, and outcomes were also reviewed. The null hypothesis was: “Appendectomy at the time of gynecologic surgery is not beneficial.”

Materials and Methods

Results

There were 920 patients who were operated on, with data captured and abstracted from the medical records. Of these patients, 69 were excluded as not applicable (NA) due to extraperitoneal or palliative procedures. These included lower genital-tract malignancies and associated procedures, intraperitoneal port placement, or bowel diversion for palliative care only.

There were 305 patients who had a primary diagnosis of uterine cancer, 182 had a primary diagnosis of high-grade serous tubo-ovarian cancer (HGSTOC), and 35 patients had a primary diagnosis of cervical cancer. Among the remaining patients, 273 had benign final pathology, including endometriosis, benign ovarian cysts, or fibroid uteri. Twenty-four patients had other cancers that were identified at surgery, including breast, pancreatic, neuroendocrine, colon/rectal, epithelial appendage, and lymphoma. Presenting diagnoses of patients with benign diagnoses varied, but included adnexal mass, pelvic pain, and pelvic mass.

There were 537 appendectomies performed. Of the total 920 patients, 110 had prior appendectomy; thus, 72% of all patients had appendectomy.

Fourteen (2.97%) primary appendiceal cancers were identified: 6 had carcinoid histology and 8 had mucinous histology. Two were managed at the time of gynecologic surgery with intraoperative pathology lending a diagnosis and definitive management, including bowel resection, and/or debulking, and peritoneal stripping by a gynecologic oncologist. Twelve primary appendiceal tumors were identified postoperatively on final pathology: 2 were managed with subsequent second surgeries; 10 were managed conservatively due to tumor size <2 cm, no lymphovascular space invasion, lack of high pathologic risk factors, patients' refusals (2) to undergo hemicolectomy, or advanced gynecologic malignancy taking priority.

Fifty-four appendix specimens (11.3%) had metastatic gynecologic cancer (52 metastatic HGSTOC, and 2 metastatic serous uterine). No patient was upstaged based on appendiceal pathology, but all patients were optimally debulked by inclusion of the appendectomy.

Of the 24 other cancers identified, 12 were metastatic to the appendix. These included breast, colon, unknown primary adenocarcinoma, neuroendocrine unknown primary, and pancreatic cancers.

There were 16 cases (3.3%) of acute appendicitis identified. Most patients were symptomatic with pelvic or localized right lower-quadrant pain but this was characterized as gynecologic in origin due to coexisting adnexal masses identified on imaging. All adnexal masses were benign in this patient population.

The average age of all patients was 74.36. The average age of the patients with primary appendiceal cancer was 59.14. The average age of those with acute appendicitis was 47.92. The average age for patients with gynecologic tumor metastatic to the appendix was 62.7. There were no complications identified from performing the appendectomy procedure.

Two hundred and four patients with no prior appendectomy did not have appendectomy performed: 2 refused to consent to the possibility of the procedure; in 60, it was not possible to visualize the appendix due to retrocecal position; 21 patients had extensive adhesions documented, prohibiting a safe incidental procedure; and in the remaining 121, there was no documented reason for not performing the procedure. Of these 121, all occurred prior to April 2013, when the practice did not routinely obtain consent for the procedure and perform it.

BMI and route of surgery did not affect the ability to perform an appendectomy. The BMIs of the patients who did not have any appendectomy was 33.97, compared to a BMI of 31.45 for those who did have an appendectomy performed (t-test; p = 0.9679). The BMI of the laparoscopic group with no appendectomy was 34.37. The BMI of the laparoscopic group who had appendectomy was 32.80. There was no difference in BMI affecting ability to perform appendectomy (t-test; p = 0.9759, nonsignificant [NS]).

Stratifying by date prior to April 2013, 46 appendectomies were performed of a total of 219 procedures, giving a rate of 26%. Between April 2013 and July 2016, 491 appendectomies were performed of 701 total procedures, achieving a rate of 87%, which was 4 times higher (sign test; p = 0.001). Routes of surgery were equally balanced between open and laparoscopic approaches. There were 406 laparoscopic/robot-assisted procedures and 338 exploratory laparotomy procedures. Excluding the NA procedures, 183 procedures occurred before April 2013; of these, 91 were laparoscopic and 92 were laparotomy, and there was no difference in rate of appendectomy (t-test; p = 0.9945, NS). Again, excluding the NA procedures, 657 procedures occurred after April 2013 with 303 via laparoscopy and 354 via laparotomy, and there was no difference in rate of appendectomy (t-test; p = 0.9226, NS). Minimally invasive approaches were desirable, but mass size, presenting symptoms, or patient comorbidities led to selection of an appropriate laparotomy route.

Discussion

Routine incidental appendectomy is a safe and feasible procedure. There was a high rate of incidental primary appendiceal cancer identified at 2.97% in this review population. This is compared to the general U.S. population rate of 0.5% of all appendiceal cancers identified, and 1% of all appendectomy specimens examined for appendicitis. ⁷ An appendectomy contributed to optimal debulking in all 54 patients with metastatic serous cancer. In patients with pelvic pain and endometriosis, appendectomy identified “other” pathology, including a diagnostic etiology of cause (infection—acute or chronic appendicitis—and endometriotic implants), thus explaining the pain symptoms.

The findings from this chart review advocate for the safety of appendectomy at the time of gynecologic surgery. The review also shows potential benefits with regard to finding occult cancers. The procedure takes an average of 4 additional minutes for a nonretrocecal location. The outcomes were favorable for the cases in this chart review. Many gynecologic surgeons are not comfortable with performing this procedure, but, with the low rate of complications (0%), it is possible to teach these simple techniques to enable a higher procedural rate. Gynecologists can then consider performing appendectomy at the time of routine pelvic surgery.

Limitations of this study were a single-provider practice, lower power with a small number of patients, and the retrospective review design. The low rate of complications might be due to a single, high-volume practice; the risk of complications, cost, and time to perform appendectomy might not, however, be reflective of routine practice.

Conclusions

In the high-risk gynecologic population studied, appendectomy helped identify incidental and/or synchronous primary appendiceal cancers, and reduce risk for future appendicitis. The risk reduction for appendicitis occurs in both a general patient population and in an immunocompromised population during adjuvant therapies in those patients with advanced stage gynecologic malignancies. Further investigation into a common genetic etiology of appendiceal cancers concordant with gynecologic malignancies based on the current review of incidental appendectomy procedures can also be investigated.