Management of Intestinal Obstruction in the Patient With Ovarian Cancer
Management of Intestinal Obstruction in the Patient With Ovarian Cancer
Intestinal obstruction in the patient with ovarian cancer is a difficult situation for both patient and physician. In women presenting with ovarian cancer, obstruction is almost never complete. These women should undergo aggressive bowel surgery only if it is part of an optimal surgical cytoreduction. Women known to have ovarian cancer who develop intestinal obstruction have a poor prognosis: Few will live more than a year from the time of obstruction. Some, however, have an excellent performance status, and would be relatively unimpaired were it not for their obstruction. These women, who usually have a discrete obstruction and still display some response to chemotherapy, may benefit from surgical correction of the obstruction. Women who are not candidates for surgery can be effectively palliated pharmacologically so that they are comfortable with the obstruction, often without intestinal drainage. Algorithms are available to assist in the management of ovarian cancer patients with obstruction, but ultimately the treatment decision rests with the patient. The oncologist must use his or her knowledge and clinical judgment to help the patient develop an appropriate, individualized plan. [ONCOLOGY 14(8):1159-1163, 2000]
Ovarian cancer afflicts more than 26,600 women in the United States each year, and over 14,500 die of the disease. It is thus the deadliest gynecologic malignancy, associated with more fatalities than all the other gynecologic cancers combined. Most patients with ovarian cancer present with advanced disease, with tumor spread throughout the abdominal cavity. It is less common to find extra-peritoneal disease at presentation, and frequently, the tumor remains confined to the peritoneal cavity throughout the natural history of the disease.
Regrettably, many women with ovarian cancer experience bowel obstruction. This may occur on presentation or, more often, as a sign of progressive disease with ensuing death. It is critical for the physician participating in the care of women with ovarian cancer to have an understanding of the disease itself and the patient’s clinical course, expectations, and expected outcomes.
For many women with ovarian cancer, bowel obstruction is a sign of imminent demise. With this understanding, most surgeons have modified their approach over the past several decades—from one of reflexively operating on the patient with intestinal obstruction of any cause to one of greater individualization. Almost all women with intestinal obstruction will live less than a year, and the majority will live less than 6 months. Conservative management of obstruction, as we will review, is not necessarily associated with more rapid death. Many published series have demonstrated that surgery is feasible, reasonably safe, and appears to improve quality of life in the majority of cases. These series have been reported from a variety of renowned gynecologic oncology centers, suggesting that surgery should not automatically be considered inappropriate.
There have been no prospective randomized trials to date comparing surgery to conservative management. Given the dire straits that most women are in at the time of such interventions, a randomized trial seems unlikely to occur. It would be valuable, however, to rigorously measure quality of life in women managed surgically or conservatively in this situation. Until such information becomes available, the practicing physician must offer management options to patients based on the information that has been gathered to date. To this end, we will briefly review the natural history of ovarian cancer, the options for the initial and long-term management of intestinal obstruction in ovarian cancer patients, the predictors of the success and failure of such an intervention, and the techniques of surgery or medical management.
The surgeon managing a patient with ovarian cancer must understand as much as possible about the biology and behavior of the disease. This understanding is as vital to successful management as is a thorough knowledge of anatomy and proper surgical technique. It is essential to thoroughly evaluate and document where the patient is in the management of her disease. The implications of major surgery in a patient with a good performance status who will likely respond to therapy are very different from those of a similar surgery in a medically compromised patient who has exhausted all treatment options.
Epithelial ovarian carcinomas, which constitute approximately 90% of malignant ovarian neoplasms, spread to adjacent organs by direct extension, by lymphatic channels, and by dissemination of cells through the peritoneal cavity. Hematogenous spread is rare. The dissemination of clonogenic cells through the peritoneal cavity is the most significant extraovarian spread of epithelial tumors. Malignant cells have been found in the peritoneal cavity even in cases where the ovarian capsule is intact.
Once these cells have entered the peritoneal cavity, they appear to follow the normal circulation of the peritoneal fluid: up the right paracolic gutter, across the diaphragm from right to left, and down the left paracolic gutter. This pattern seems to be the result of both the respiratory motion of the diaphragm and the peristalsis of the bowel. Further peristaltic movement of the intestine can result in implantation on any of the peritoneal surfaces, including the mesentery and serosa of the large and small bowel.
Consistent with this predominantly intraperitoneal pattern of spread is the observation that implants of ovarian cancer on the intestines rarely invade the muscalaris propria. Even when complete obstruction is documented, the process is nearly always one of extrinsic compression rather than intraluminal obliteration. This is found even in the setting of advanced disease with bulky omental and/or pelvic encasement of tumor.
The lymphatic vessels of the ovary follow the course of the ovarian blood supply in the infundibulopelvic ligaments to terminate in the high para-aortic lymph nodes between the inferior mesenteric artery and the renal vessels. Collateral drainage occurs via the lymphatic channels in the broad ligament to the external iliac and hypogastric lymph nodes and via lymphatics in the round ligament to involve the inguinal lymph nodes.[5-7] In advanced ovarian cancer, the retroperitoneal lymph nodes are involved in 60% to 70% of patients. Thus, evaluation and excision of the retroperitoneal lymph nodes may be an important component of an optimal surgical cytoreduction for ovarian cancer (see below).
The initial management of ovarian cancer involves surgical exploration with systematic surgical staging for patients with apparent early-stage disease and aggressive surgical cytoreduction for patients with gross extraovarian disease. Clinical trials of surgical staging have demonstrated that, among women felt to have disease confined to the ovary at the time of laparotomy, 30% will be found to have occult metastases after thorough surgical staging.[8,9] An extensive body of retrospectively and prospectively acquired data has demonstrated that removal of all implants larger than 1 to 2 cm is associated with a dramatically increased survival. This has been demonstrated even in patients with stage IV disease.
Bristow and colleagues, for example, reported that women with stage IV disease who underwent cytoreduction to < 1 cm disease had a median survival of 38 months, while those with stage IV disease and > 1 cm residual tumor had a median survival of 10 months. This was found to be the case even when liver resection was required to attain optimal cytoreduction. It should be noted, however, that such aggressive surgical efforts are not associated with an improvement in survival unless all disease of 1 cm diameter or larger is removed.
Although it is commonly observed that the rate of cure of ovarian cancer has not changed significantly over the past 30 years, it is important to recognize that the duration of survival and quality of life of women with advanced ovarian cancer has improved dramatically over that interval. Much of this improvement is due to the stepwise evolution of chemotherapy regimens from single alkylating agents to combination chemotherapy regimens, and ultimately the emergence of platinum-based regimens.
In reporting the addition of paclitaxel (Taxol) to platinum-based therapy for ovarian cancer, McGuire and colleagues observed a median survival of 38 months for women with surgically suboptimal disease. This is in marked contrast to the median survival reported in trials of single alkylating agent therapy, which was generally found to be about 14 months. An important component of this improvement in survival is the fact that close to 70% of women with advanced ovarian cancer will achieve complete clinical remission after initial surgery and platinum-based chemotherapy. Thus, many women with significant gastrointestinal symptoms, or with intraoperative findings suggesting imminent bowel obstruction at the time of presentation will achieve complete resolution of their symptoms (at least transiently) even in the absence of an aggressive surgical effort.
Intestinal Obstruction in the Patient Presenting With Ovarian Cancer
Given the predilection of ovarian cancer for intraperitoneal spread, many patients are found to have symptoms of intestinal compromise when they present with ovarian cancer. This is most commonly caused by compression of the rectosigmoid by pelvic tumor or involvement of the transverse colon with a bulky omental tumor. In patients with such symptoms, a preoperative barium enema or colonoscopy is often helpful to exclude a primary colonic malignancy.
As suggested above, even patients with apparent extensive intestinal involvement at the time of presentation rarely benefit from aggressive bowel resection unless this effort is performed for a complete obstruction or as part of an optimal surgical cytoreduction. Surgeons experienced in the management of ovarian cancer are generally able to dissect bulky tumors from the bowel serosa, and thus achieve an optimal cytoreduction without resorting to intestinal diversion or resection.