Impact of bariatric surgery on oral anticancer drugs: an analysis of real-world data.

PURPOSE: The number of patients with bariatric surgery who receive oral anticancer drugs is rising. Bariatric surgery may affect the absorption of oral anticancer drugs. Strikingly, no specific drug dosing recommendations are available. We aim to provide practical recommendations on the application of oral anticancer drugs in patients who underwent bariatric surgery. METHODS: Patients with any kind of bariatric surgery were extracted retrospectively in a comprehensive cancer center. In addition, a flowchart was proposed to assess the risk of inadequate exposure to oral anticancer drugs in patients who underwent bariatric surgery. Subsequently, the flowchart was evaluated retrospectively using routine Therapeutic drug monitoring (TDM) samples. RESULTS: In our analysis, 571 cancer patients (0.4% of 140.000 treated or referred patients) had previous bariatric surgery. Of these patients, 78 unique patients received 152 oral anticancer drugs equaling an overall number of 30 unique drugs. The 30 different prescribed oral anticancer drugs were categorized as low risk (13%), medium risk (67%), and high risk (20%) of underdosing. TDM plasma samples of 25 patients (82 samples) were available, of which 21 samples post-bariatric surgery (25%) were below the target value. CONCLUSIONS: The proposed flowchart can support optimizing the treatment with orally administered anticancer drugs in patients who underwent bariatric surgery. We recommend performing TDM in drugs that belong to BCS classes II, III, or IV. If more risk factors are present in BCS classes II or IV, a priori switches to other drugs may be advised. In specific cases, higher dosages can be provided from the start (e.g., tamoxifen).

Survival analysis of pseudomyxoma peritonei patients treated by cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

OBJECTIVE: To evaluate the survival of patients with pseudomyxoma peritonei (PMP) treated by cytoreductive surgery and intraoperative hyperthermic intraperitoneal chemotherapy (HIPEC), and to identify factors with prognostic value. SUMMARY BACKGROUND DATA: PMP is a clinical syndrome characterized by progressive intraperitoneal accumulation of mucous and mucinous implants, usually derived from a ruptured mucinous neoplasm of the appendix. Survival is dominated by pathology. METHODS: A total of 103 patients (34 men and 69 women) treated at The Netherlands Cancer Institute between 1996 and 2004 were identified. Survival was calculated from date of initial treatment and corrected for a second procedure. PMP was pathologically categorized into disseminated peritoneal adenomucinosis (DPAM), peritoneal mucinous carcinomatosis (PMCA), and an intermediate subtype (PMCA-I). Clinical and pathologic factors were analyzed to identify their prognostic value for survival. RESULTS: Median follow-up was 51.5 months (range, 0.1-99.5 months). Recurrence developed in 44%. A second procedure for recurrence was performed in 11 patients. The median disease-free interval was 25.6 months (95% confidence interval [CI], 14.8-43.6 months). The 3-year and 5-year disease-free survival probability was 43.6% (95% CI, 34.4%-55.2%) and 37.4% (95% CI, 28.2%-49.5%), respectively. The disease-specific 3-year and 5-year survival probability was 70.9% (95% CI, 62.0%-81.2%) and 59.5% (95% CI 48.7%-72.5%), respectively. Factors associated with survival were pathological subtype, completeness of cytoreduction, and degree and location of tumor load (P < 0.05). The main prognostic factor, independently associated with survival, was the pathologic subtype (P < 0.01). CONCLUSION: Cytoreductive surgery in combination with intraoperative HIPEC is a feasible treatment strategy for PMP in terms of survival. The pathologic subtype remains the dominant factor in survival. Patients should be centralized to improve survival by a combination of surgical experience and adequate patient selection.