The Quality of Life of Pseudomyxoma Peritonei Patients: A Scoping Review

Background . Pseudomyxoma peritonei (PMP) is a form of peritoneal malignancy. It originates from a perforated appendiceal epithelial tumour. Patients with PMP experience various stressful and traumatic events including diagnosis with a rare disease, treatment with extensive and complex surgery, and long hospital stays. Currently, there is a scarcity of studies that primarily aim to assess the quality of life of patients with PMP, and there is no reviews or comprehensive understanding of the quality of life (QoL) issues faced by these patients. Even fewer studies have consulted with patients themselves. Objective . To review the current literature on the QoL of patients with PMP and answer two main questions: What methods are being used to assess the QoL patients with PMP and what are the main fndings?. Methods . For the scoping review, fve scientifc databases were searched (CINAHL, EMBASE, Pubmed, PsycInfo, and Medline). Publications that were published between 2002 and 2022 and in English were included in this review. Studies were screened by two independent reviewers against the review’s eligibility criteria. Data related to the QoL of patients with PMP in the included studies were extracted to answer two main questions (what were the methods used to assess QoL in this population, and what were the fndings?). Te extracted data was presented in table form and qualitatively analyzed using content analysis. Findings . Fourteen studies were included in this review. Only fve studies out of fourteen assessed the QoL of patients with PMP as a main outcome, and all these studies assessed QoL in relation to surgery. Studies that assessed QoL used diferent validated measures. Tere was a consensus among studies that patients’ QoL improved by 12 months posttreatment. Te most commonly cited symptom of PMP in this review is abdominal pain. Conclusion . Te evidence on the QoL of patients with PMP is limited. Studies that assess the quality of life of these patients independent of surgery are needed. Tere is no consensus on the measure used to assess QoL in this population.


Introduction
Pseudomyxoma peritonei (PMP) is a form of peritoneal malignancy [1].It originates from a perforated appendiceal epithelial tumour and afects 22 individuals per million worldwide [1,2].Te cancer spreads along the peritoneum, a thin layer that protects the abdominal organs, and can involve the surface of all abdominal organs [3].Without treatment, PMP is a fatal condition [4].Te unlimited multiplication of peritoneum cells can fll the space needed in the abdomen for normal gastrointestinal functioning, leading to compression of bowel organs, disruption of their functioning, and starvation [5].
Te most common treatment for PMP is cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC) [5].CRS entails removing the peritoneum and other afected tissues [5].CRS is an extensive and complex surgery [4].HIPEC is a therapy that uses chemotherapy that is applied directly to the abdomen [5].Patients with PMP experience various stressful and traumatic events, including diagnosis with a rare disease, treatment with extensive and complex surgery, admission to intensive care for an average of 5 days, and then on a surgical ward for an average of 3 weeks [6].
Tere are a few studies that primarily aim to assess the quality of life of patients with PMP [7][8][9][10] but there is no systematic or comprehensive review of the literature.A review is needed for a better understanding of the fndings around the quality of life of patients with PMP.Collating and reviewing the current fndings will help inform clinicians and patients and will guide future research by highlighting current knowledge gaps.

Materials and Methods
Te authors' initial aim was to conduct a systematic review of the literature on the quality of life of patients with PMP.However, after the initial search, it was decided that a scoping review would be more appropriate, as the current literature on the quality of life of patients with PMP is too limited.Scoping reviews are used to answer specifc questions, summarize the characteristics of the studies that have been published in the feld, and identify knowledge gaps [11].Tus, a scoping review would allow the authors to answer their questions about the quality of life of patients with PMP from the limited research available.Te Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) was used to structure this review [12].

Objectives.
Te main objective of this scoping review was to answer the following questions: (1) What are the main methods/questionnaires used to assess the quality of life (QoL) of the patients with PMP? (2) What are the current main fndings around the QoL of patients with PMP?

Selection of Sources of Evidence.
Te initial search resulted in 896 results of which 14 studies were included in this review.See Figure 1 for the PRISMA fowchart [14].

Characteristics of Sources of Evidence.
Te included studies in this review were published between 2004 and 2018.Studies were geographically well spread (UK, Japan, France, Australia, India, Finland, Denmark, Hong Kong, and Saudi Arabia).Tey included one review [15], two case studies [16,17], one qualitative study [5], and ten quantitative studies [7][8][9][10][18][19][20][21][22][23].See One study reported that patients had a good quality of life without using/reporting a quality-of-life measure [21].It is notable that only one of these questionnaires (CR38) is specifc to a specifc cancer site, in this case colon cancer, and that there are no questionnaires that have been developed for peritoneal malignancy.

Synthesis of Results.
One study that assessed PMP symptoms reported that the most common symptom is abdominal pain (23% of a sample of 82 patients with PMP) [18], fve out of seven patients who had a major debulk surgery (incomplete surgery where surgeons were unable to remove all the disease) experienced symptom relief [22], and patients who undergo a major debulk surgery experience symptom relief over a median time of 2 years [20].
A study that compared the quality of life of patients with PMP who had complete surgery (removed all disease) with those who had a major debulking (some disease left) found that quality of life dropped at 1-month posttreatment and returned to baseline at 3 months in both groups; however, QoL continued to improve after that only in patients who had a complete surgery [8].A study that compared the quality of life of those who had a single surgery to those who had a redo (surgery for recurrence) reported that there was no signifcant diference between the two groups [7].In both groups, quality of life was impaired between 6 and 12 months and returned to baseline levels at 12 months [7].Two studies assessed the quality of life of patients with PMP post-CRS and HIPEC: one reported that CRS and HIPEC had "little impact" on quality of life and that quality of life returned to baseline 6 months posttreatment [9], and the second reported that patients had a good quality of life at 12 months' posttreatment except for impairment in their cognitive function and bowel disturbances [10].Patients who had a total gastrectomy or a total colectomy had a similar quality of life at 6 months compared to other patients [19].In one study, 61% of the sample had a stoma, but that was found to have no infuence on their quality of life [9].

Discussion
Tis is the frst review of the literature on the quality of life of patients with PMP.Te results show that the evidence on the quality of life of patients with PMP is limited.Only fve research studies assessed quality of life in this population as a main outcome, and all fve studies assessed quality of life in relation to treatment [7][8][9][10]23].Tere is no consensus on the questionnaire used to measure quality of life in this population.Five diferent questionnaires were used to assess quality of life in this population (FACT C (version 4), FACIT-TS-G (version 1), the European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30, SF-36 (acute version), and the EORTC QLQ-CR38) despite the very few papers assessing quality of life in patients with PMP.A systematic review on the Qol of ovarian cancer survivors found that sixty diferent measures were used to assess Qol in their population [24].Tere have already been calls for the standardization of the measures used to assess Qol in these populations; standardized measures will allow researchers to compare fndings and reach conclusions [25].
Another important fnding of this review is that quality of life in this population was mainly assessed by surgeons/ surgical departments to provide evidence that the treatment (surgery) does not impair quality of life in the long term.Tus, the data on the quality of life of patients with PMP living with the disease can only be found in the data collected at baseline (pretreatment) in these studies.Patients' quality of life at baseline/presurgery may not be representative of the quality of life of patients with PMP living with the disease.Tree out of the fve studies that assessed quality of life compared the quality-of-life posttreatment with baseline levels [7][8][9].It is important to note that the quality of life at baseline may be impaired by the disease and that return to baseline should not be the aim for these patients.Tis is especially true given that the fndings of this review show that little is known about the issues that afect the quality of life of patients with PMP at baseline (pretreatment).Similar to quality-of-life studies in colorectal cancer, where the majority of research gathers data of up to one year postsurgery, little is known about the long term Qol of these patients [25].
4.1.Limitations.Te heterogeneity of the studies in this review makes it very difcult to make any conclusion about the QoL of patients with PMP.Tis review highlights how limited and varied the research on the Qol of patients with PMP currently is.Another limitation of this review is that it includes case reports [16,17,23], whose fndings might not be generalizable.However, these studies were included because of how limited the current literature is.Te inclusion criteria for this report (studies published between 2002 and 2022) may have excluded a few relevant papers; however, this review was concerned with the recent and current literature on the topic.

Conclusion
Te current evidence on the Qol of patients with PMP is very limited.Studies that assess the quality of life of these patients independent of surgery are needed.A consensus on the measures used to assess the quality of life in this population or the development of a measure specifc to this population is needed.Furthermore, studies that assess the Qol of palliative patients who receive these treatments (CRS and HIPEC) are needed.European Journal of Cancer Care (14)