ASPirin Intervention for the REDuction of colorectal cancer risk (ASPIRED): a study protocol for a randomized controlled trial

A single-center, academic hospital (MGH)

Potential participants will be identified within the gastroenterology practice of MGH. Eligible adults (aged 18–80 years) will have had at least one adenoma removed during a qualifying endoscopy within 9 months of study enrollment, confirmed via official pathology reports. Full inclusion and exclusion criteria are included in Table 1.

The first dose of the study medication will be provided to participants immediately upon completing the initial baseline flexible sigmoidoscopy (start of randomization). Aspirin is an odorless, white, needle-like crystalline or powdery substance. Generic aspirin is provided as an oral tablet at an 81-mg or a 325-mg dose. To maintain blinding, we use specially designed formulations in which aspirin tablets are crushed into a powder. An amount of powder that reflects the appropriate dose is then placed in a gel capsule with a lactose filler. In the case of placebo, an identically sized capsule filled only with lactose is used. Participants will be instructed to consume one study capsule per day with food and a full glass of water until they return for their final visit. The final visit will occur a minimum of 8 weeks, but no more than 12 weeks after the initial visit. The study duration is designed to maximize feasibility and compliance. Moreover, in a pilot study, two doses of 650 mg of aspirin, 14 h apart, were sufficient to reduce urinary PGE-M levels by 44% [4]. Furthermore, aspirin and other NSAID agents have been shown previously to have an effect on recurrent adenoma risk within as little as 1 year, [5, 6] which suggests that biological impact of the treatment on colonic epithelium may be reasonably measured within 2–3 months. The capsules will be packaged in a pill bottle containing 84 capsules (12-week daily supply) and participants will return any unused capsules and the bottle to study staff at the final visit. Remaining capsules will be counted as a measure of compliance. Weekly calls from study staff during this 8–12-week period will be used to monitor adherence and adverse events and promote retention. Any use of nonstudy aspirin or other NSAID during this time period will result in the participant being withdrawn from the study and an exit visit will be performed at that time. Participants will be provided with US$200 compensation and free parking for the baseline visit and US$300 and free parking for the final visit, resulting in a total of US$500 following successful completion of the study.

This trial aims to examine the post-treatment effect of low-dose (81 mg/day) and standard-dose (325 mg/day) aspirin on pretreatment urinary PGE-M. Secondary endpoints include the effects of aspirin on the following CRC-associated biomarkers:

A detailed description of the rationale for the selection of these biomarkers and their biological relevance to aspirin chemoprevention appears in the “Discussion” section.

The study timeline (Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) diagram consistent with the SPIRIT Checklist. The SPIRIT Checklist is attached as Additional file 1: SPIRIT Checklist) appears as Fig. 1. At the initial (baseline) visit, the study physician obtains written informed consent for the study, as well as a standard clinical consent for a flexible sigmoidoscopy. Following completion of this visit, the participants are considered “on treatment” (start of randomization) and take blinded aspirin or placebo daily until the end of the treatment period (8–12 weeks later). At the end of the treatment period, participants will return for a final visit during which a second flexible sigmoidoscopy will be performed. Both clinical visits are identical in their data and specimen collection approaches. Participants are asked to complete a brief lifestyle and dietary questionnaire, which is subsequently transferred (via double entry) to a secure REDCap electronic database system. Trained study staff will collect measurements of height, weight, waist and hip circumference, as well as blood (three 10-mL vials), urine (approximately 20 mL) and saliva specimens (2–3 mL). Twenty milliliters of whole blood will be immediately aliquoted and frozen at −80 °C. Ten milliliters of whole blood will be immediately centrifuged for serum and buffy coat collection, aliquoted and frozen at −80 °C. Saliva is immediately aliquoted, frozen on dry ice, and stored at -80 °C. Urine is immediately stored on wet ice, aliquoted within 1 h and frozen at −80 °C. A study gastroenterologist will then perform a flexible sigmoidoscopy, advancing to the level of the distal sigmoid colon. No bowel preparation will be necessary for the procedure. Thus, stool will be either aspirated through the endoscope or collected using a Roth net then aliquoted into cryovials, immediately frozen on dry ice, and stored at -80 °C. The gastroenterologist then identifies an area of the rectosigmoid junction, clear of any stool, to collect cellular material using an endoscopic cytology brush. The brush heads are cut and placed immediately into a tube containing 25% ethanol, then placed on wet ice until storage at 4 °C. These samples are kept cold through shipment and processed for partial wave spectroscopy (PWS) within 2 − 3 days of collection. Last, the gastroenterologist collects 24 pinch-biopsy specimens that are processed and stored under multiple conditions (e.g., formalin-fixed, paraffin-embedded; flash-frozen; culture media; etc.) for future assays. A summary of the patient assessments and biospecimens collected appears as Fig. 2.

We calculated the sample size required to estimate the effect of aspirin on our primary endpoint, urinary PGE-M, using the two aspirin groups combined versus placebo. The null hypothesis is: H ₀: Δ _aspirin – Δ _placebo = 0 versus H _A : Δ _aspirin – Δ _placebo ≠ 0, where Δ _aspirin and Δ _placebo are the mean changes in urinary PGE-M level from baseline to end of treatment for the intervention and placebo groups, respectively. Based on prior studies [4, 7, 8] we assumed a standard deviation (SD) of 5.0 for a single measurement of PGE-M and an intraclass correlation (ICC) of 0.1. We will recruit 60 participants in each group to account for the possibility of dropout (20%). Assuming 45 participants in the placebo group and 90 participants in the combined aspirin group will complete the study, we estimate 90% power to detect a mean change of PGE-M level in the aspirin group of 4.0 ng/mg, compared with no change in the placebo group, assuming a type I error rate of 0.05. This minimum detectable difference in mean change is consistent with the difference in the median level of PGE-M among individuals at high risk for adenoma compared to those with low risk [7].

Patients who meet the inclusion criteria will be identified through investigators during their routine clinical practice, supplemented by a periodic query of the MGH endoscopy and pathology databases. Potentially eligible participants are approached by letter from their treating physician. Two weeks after receiving the letter, study staff will contact eligible parties and screen for eligibility via phone interview. If eligibility is established, individuals are mailed a copy of the Informed Consent Documents (Informed Consent Documents included as Additional file 2). Written informed consent is obtained from each participant by a study physician prior to performing any study-related procedures.

The randomization schedule will not be disclosed to the investigator or any personnel involved in the conduct of the study before the database is locked, except as described here. Enrollment and randomization will be carried out by the Office of Data Quality within the Dana-Farber/Harvard Cancer Center (DF/HCC) into three arms: placebo, 81 mg/day, or 325 mg/day. Randomization assignment is dispatched directly to the MGH Research Pharmacy by the Office of Data Quality.

Neither the participant nor the study physician or any study personnel will know which of the three treatments (placebo, 81 mg/day, or 325 mg/day) the participant is receiving. The Office of Data Quality will provide randomization assignment to the MGH Research Pharmacy. The MGH Research Pharmacy will provide blinded capsules. The investigator or treating physician may unblind a participant’s treatment assignment only in the case of emergency, when knowledge of the study treatment is essential for the appropriate clinical management or welfare of the participant. If the blind is broken by the investigator, the participant will be permanently discontinued from the study and an early termination assessment will be completed. If unblinding is necessary, study staff will contact the Office of Data Quality.

Upon consent, participants will be assigned a three-digit unique identifier assigned sequentially by study staff. All data and specimens collected will be stored and labeled using this coded identifier. Data collected via questionnaires and clinical research forms will be transferred via double entry to a secure REDCap electronic database system.

The DF/HCC Data and Safety Monitoring Committee (DSMC) will review and monitor toxicity and accrual data from this study. The DSMC is composed of clinical specialists with experience in oncology and who have no direct relationship with the study. Information that raises any questions about participant safety will be addressed with the overall principal investigator and study team. The DSMC will review each protocol up to four times a year, or more often if required, to review toxicity and accrual data. Information to be provided to the committee may include: up-to-date participant accrual; current dose-level information; all grade 2 or higher unexpected adverse events that have been reported; any response information; audit results, and a summary provided by the study team. Other information (e.g., scans, laboratory values) will be provided upon request.

This study and its respective consenting procedures was approved by the DF/HCC Institutional Review Board (Protocol # 14-496) on 9 December 2014 and activated on 10 April 2015. The first participant was enrolled on 6 July 2015. The current protocol (Amendment 10/Version 12) was approved via continuing annual review on 24 October 2016.

All amendments are reviewed by the DF/HCC Institutional Review Board and communicated as necessary in writing to relevant parties.

Written, signed, informed consent will be collected by a study physician prior to any study-related procedures.

We will take measures to protect the privacy and security of all participants’ personal information, but we cannot guarantee complete confidentiality of study data. Medical information created by this research study may become part of a DF/HCC research database. The results of this research study may be published, but participants will not be identified without their permission.

Coded samples and/or data may be sent by MGH or DF/HCC to other researchers who are also studying aspirin chemoprevention and/or collaborating with the study team including, but not limited to, the National Institutes of Health, the Ragon Institute, the Dana-Farber Cancer Institute, Children’s Hospital, Vanderbilt University, the Broad Institute, Northwestern University, and the Harvard T.H. Chan School of Public Health. All other scientists and/or collaborators must meet MGH requirements for sharing samples and/or data including treating the data or materials as medically confidential, obtaining approval from their Human Subjects Review Boards, and agreeing not to share the data or materials with other parties. Affiliated researchers or laboratories outside of DF/HCC and MGH will never know who a participant is, nor have access to the code linking the samples back to the participants.

The results should be made public within 24 months of reaching the end of the study. The end of the study is the time point at which the last data items are to be reported, or after the outcome of data are sufficiently mature for analysis as defined in the statistical analysis section. We plan to publish in a peer-reviewed journal; thus, the initial release may be an abstract that meets the requirements of the International Committee of Medical Journal Editors. A full report of the outcomes should be made public no later than 3 years after the end of the study. Results will also be available through ClinicalTrials.gov.