We used a large, population-based database to investigate the incidence, management, and outcomes of obstruction in ovarian cancer patients. We modeled predictors of inpatient hospitalization for bowel obstruction after cancer diagnosis, categorized management of obstruction, and analyzed the associations between treatment for obstruction and outcomes.
Of women with ovarian cancer, Surgical management of obstruction was associated with lower day mortality Median post-obstruction survival was days in women with obstructions of adhesive origin and 93 days in others. While obstruction due to adhesions did not signal the end of life, another bowel obstruction ovarian cancer other obstructions were pre-terminal events for the majority of patients regardless of treatment.
Death due to cancer can involve painful and care-intensive complications, demanding palliative treatments sensitive to patient needs.
One such complication is bowel obstruction, wherein recurrent abdominal or pelvic cancer leads to a blocked intestinal tract, which in turn results in nausea, vomiting, and dehydration[ 1 another bowel obstruction ovarian cancer. Obstruction usually requires inpatient hospitalization[ 23 ] and may be the proximal cause of death[ 45 ], another bowel obstruction ovarian cancer.
Obstruction management options can be broadly categorized into surgical treatments, another bowel obstruction ovarian cancer, such as bypasses or colostomies, and non-surgical treatments, such as bowel rest with decompression, pharmacological management, or endoscopic placement of a stent at the obstruction site[ 9 ], another bowel obstruction ovarian cancer.
There exist no formal guidelines for treatment[ 3 ], in part because some studies have found surgery to be associated with improved survival[ 4710 ] while others have found no survival benefit to surgery or attribute minor survival differences to patient selection[ 611 ]. To date, most studies of bowel obstruction management and outcomes in the context of recurrent ovarian cancer have been hospital-based and had small sample sizes[ 4 810 another bowel obstruction ovarian cancer 15 ].
In this study, we estimate the incidence of obstruction in a population-based sample of ovarian cancer patients, using the Surveillance, Another bowel obstruction ovarian cancer and End Results SEER and Medicare claims linked databases[ 16 ]. We also investigate factors associated with bowel obstruction, treatment of bowel obstruction, and outcomes after a hospitalization for obstruction. Subjects diagnosed exclusively by death certificate or autopsy, those for whom the month of diagnosis was unknown, and those who had Medicare coverage owing to disability or late-stage renal disease rather than age were excluded.
We also excluded individuals enrolled in a non-Medicare health maintenance organization at any time from cancer diagnosis to death, as billing claims for these patients may not have been submitted to Medicare for reimbursement. We extracted patient characteristics, including age, race, marital status, date of diagnosis, and tumor characteristics from SEER registry files.
We categorized age in five-year increments, another bowel obstruction ovarian cancer, and another bowel obstruction ovarian cancer as white, black, and other or unknown.
We considered subjects divorced, separated, single, and widowed at the time of diagnosis to be unmarried. We grouped patients by year of diagnosis , , and and appointed the diagnosis date as the 15 th day of the month of diagnosis. We classified tumor histology as serous, mucinous, endometrioid, or other.
We grouped tumor grade into low well or moderately differentiatedhigh poorly differentiated or undifferentiatedand unknown according to ICD code[ 19 ]. We categorized patients as having had primary tumor resection PTR or no PTR on the basis of a physician or hospital claim for oophorectomy, exenteration, another bowel obstruction ovarian cancer, or hysterectomy codes in Appendix 1 within six months toradol and genitourinary bleeding diagnosis.
We considered hospitalization at an acute care hospital after cancer diagnosis in which an ICD-9 diagnosis code for bowel obstruction was recorded Under the assumption that an obstruction of adhesive etiology might be coded as non-specific obstruction but that malignant obstruction was unlikely to be coded as adhesive, analysis of this subset gave us a view of potential differences in factors affecting obstruction etiology by etiology, zithromax and glucose one diluted by likely misclassification.
We categorized patients as receiving chemotherapy based on Medicare claims files. We categorized patients as having ascites by ICD-9 diagnosis codes Finally, we excluded individuals with a history of bowel obstruction prior to cancer diagnosis to ensure use of an obstruction code did not represent a history of obstruction.
To assess comorbid disease in our cohort, we used the Klabunde adaptation of the Charlson comorbidity index[ 21another bowel obstruction ovarian cancer ], another bowel obstruction ovarian cancer.
We analyzed Medicare inpatient and outpatient claims for ICD-9 diagnostic codes[ 23 ] for each of 19 health conditions, requiring the appearance of the code to predate cancer diagnosis. We then compiled codes into a composite comorbidity score for each patient[ 21 ]. Individuals with no matching claims 8. We considered a physician or hospital claim for gastroenterostomy, entero-enterostomy, bowel resection, enterostomy, another bowel obstruction ovarian cancer lysis of peritoneal adhesions codes provided online in Appendix 1 to represent surgical therapy.
We did not consider an isolated claim for laparotomy or laparoscopy to constitute surgical therapy in the absence of secondary procedure codes because it is unclear whether surgical correction of the obstruction was attempted. We used hospital claims files to calculate length of stay and considered horizontal transfers to another acute care hospital part of the same hospitalization.
For each patient who had died at the time of last follow-up, we calculated days of life remaining after first post-diagnosis obstruction. We examined all Medicare hospital claims that post-dated the initial claim for obstruction to assess hospital re-admission rates, post obstruction chemotherapy rates, and to compute a ratio of days in to days out of the hospital post-obstruction.
We used univariable Cox proportional hazards models to assess predictors of time to hospitalization for bowel obstruction and post-obstruction survival. We used Kaplan-Meier curves to compute survival times, another bowel obstruction ovarian cancer, median time to obstruction and length of hospital stay. Time-to-obstruction models used date of PTR or cancer diagnosis if no PTR as time 0, and treated both death and loss to follow-up as censoring events.
The assumption of proportionality was assessed visually. All statistical tests were two-sided and we considered a p-value less than 0. We used SAS 9. We excluded 56 women who had a diagnosis of bowel obstruction prior to the cancer diagnosis. The final cohort was composed of women, Of the final cohort, Among the hospitalized for obstruction, In the group with any obstructions, the first post-diagnosis obstruction occurred a median of IQR days after cancer diagnosis.
Table 1 shows the demographic and clinical characteristics and tumor features of the subjects, stratified by hospitalization for bowel obstruction after cancer diagnosis.
Because the incidence of obstruction was closely tied to survival time, another bowel obstruction ovarian cancer, associations were assessed with univariable Cox-proportional hazard usb modems and provider plans these p-values are shown in Table 1.
The median age of the cohort was 75 IQR 71 A multivariable Cox proportional hazard model to determine predictors of obstruction is shown in Table 2. Mucinous tumor histology was also associated with elevated risk HR 1. Other factors associated with increased risk included higher stage, younger age at diagnosis and earlier year of diagnosis. Ascites and PTR at diagnosis were not significantly associated with obstruction after accounting for other factors.
Multivariable Cox Proportional Hazard analysis of association between clinical and tumor characteristics in stage IC-IV ovarian cancer patients diagnosed in SEER-Medicare database between and and bowel obstruction. Table 3 shows predictors of management strategy among the group that antibacterial ointment for foot tattoos hospitalized another bowel obstruction ovarian cancer obstruction.
Surgery for obstruction was not associated with tumor histology or history of chemotherapy. Predictors of obstruction management strategy among women with post-diagnosis bowel obstruction the context of ovarian cancer diagnosed between and in SEER-Medicare. Surgical management of first post-diagnosis obstruction was also associated with longer median survival after obstruction days vs.
While surgical management was associated with lower hazard of death in a univariable Cox proportional hazards model HR 0. Table 4 shows selected outcomes of hospitalizations for first post-diagnosis obstruction, stratified by management strategy.
Those managed surgically were more likely to spend time in the ICU Selected outcomes of women hospitalized for bowel obstruction between and in SEER-Medicare, another bowel obstruction ovarian cancer, stratified by management strategy. Stage also retained an attenuated but still significant association HR 2.
In this study of women diagnosed with ovarian cancer after another bowel obstruction ovarian cancer 65, Subsequent obstruction was associated with mucinous tumor histology, younger age, earlier year of diagnosis and history of obstruction at time of cancer diagnosis.
About 1 in 4 obstructions were managed surgically, and the median survival after obstruction was poor unless the obstruction appeared to be due to adhesive disease. Surgical management of obstruction was not associated with improved survival, nor was it associated with fewer hospital visits or a greater proportion of life outside of the hospital after obstruction. The rate we observed may be an underestimate of the true lifetime rate of bowel obstruction in ovarian cancer patients for several reasons.
First, because we considered only inpatient hospitalizations with billing codes from the hospital stay to constitute obstruction, we may zyprexa and elderly dosing missed partial obstructions that resolved without hospitalization[ 27 ].
Second, our cohort was limited to women over age 65, two years above the median age of ovarian cancer onset[ 28 ], while younger age at diagnosis appears to be associated with obstruction. If the lifetime obstruction rate is highest in women diagnosed below age 65, our cohort was enriched with women less likely to develop obstruction. Third, lifetime obstruction rates may include obstructions that occur at use of antibacterial soap before diagnosis; we counted only post-diagnosis obstructions.
In our final incidence model, the strongest predictor of obstruction after diagnosis was higher stage HR 4. This conclusion is supported by a another bowel obstruction ovarian cancer analysis showing the association with stage was lessened when follow-up was complete across all stages.
Obstruction at diagnosis was also associated with significantly elevated risk of obstruction after diagnosis HR 2.
We cancer and iron anemia found mucinous tumor histology to be associated with an elevated hazard of obstruction; this is consistent with results we found in a study of predictors of bowel obstruction in another bowel obstruction ovarian cancer context of colon cancer[ 30 ]. Further, it has been suggested that the etiology of mucinous ovarian cancer is separate from that of other histologic subtypes[ 3132 ], and that mucinous ovarian tumors are associated with worse prognosis and poorer response to chemotherapy[ 3334 ]; it is possible mucinous tumors are similarly associated with greater risk of obstruction.
However, it is also possible this apparent risk is simply an artifact of misdiagnosis of women presenting with ovarian masses and mucin in the abdomen due to metastatic non-ovarian cancer[ 35 ]; unfortunately, we are unable to assess either hypothesis from SEER-Medicare data alone, another bowel obstruction ovarian cancer. While there are no formal guidelines for treatment decisions, it is generally agreed that patients with poor prognostic status are unlikely to benefit from palliative surgery[ 141336 ].
Interestingly, history of prior chemotherapy did not appear to play a role in determining management strategy, though chemotherapy failure has been suggested as a factor determining appropriateness of surgical intervention[ 13 ].
In spite of the improved prognosis among patients selected for surgery, surgery was not associated with an increased probability of receiving chemotherapy after obstruction. Surgery was not associated with a decrease in readmission rate for obstruction, consistent with Bryan, et al. However, those managed surgically did survive about two months longer than those managed non-surgically, consistent with results reported in several hospital studies[ 4710 ].
This survival benefit was coupled another bowel obstruction ovarian cancer more post-obstruction time spent in the hospital, such that percent of life after obstruction spent in the hospital was equivalent between surgical and non-surgical groups, consistent with a trend we previously observed examining obstruction outcomes in the context of stage 4 colon cancer[ 37 ]. This result is consistent with previous reports that obstructions of benign origin are associated antibacterial and preclinical studies and university better survival[ 838 ].
While the use of ever- status to categorize obstruction etiology may have resulted in misclassification, we have no reason to believe any misclassification would be differential by survival.
Additionally, as SEER-Medicare draws from a population-based sample, it is reasonable to believe our results can be generalized to other populations of elderly women with ovarian cancer. However, the study also has limitations. Owing to a lack of specific codes, we were unable to fully distinguish obstructions of malignant origin from benign obstructions and small bowel from colonic obstruction. We were unable to assess many post-obstruction prognostic factors from Medicare claims alone, including nutritional status[ 13 ], serum albumin[ 39 ], and extent of peritoneal spread[ 1 ], limiting our ability to understand why a treatment choice was made.
Additionally, we were unable to distinguish chemotherapy given intra-peritoneally rather than intravenously, to assess whether optimal tumor debulking occurred at cancer diagnosis, or to assess the site of obstruction, all of which might have effects on obstruction incidence and outcomes. We were unable to assess the use of several palliative techniques, including stenting at the point of obstruction and anti-secretory medications such as octreotide. Finally, we were unable to assess whether treatments chosen successfully palliated symptoms, an outcome vital to developing management guidelines in this context.
In conclusion, bowel obstruction in the context of advanced ovarian cancer frequently signals the end of life.
Obstruction occurs in about 1 in 5 ovarian cancer patients and unless the obstruction is of adhesive origin, median survival is poor regardless of management strategy. These results support clinical treatment of malignant bowel obstruction as a pre-terminal event; in this context, management decisions should be made to optimize patient comfort rather than increase patient survival.
Selection, diagnosis, and treatment codes used in the creation and classification of ovarian patients in SEER-Medicare.