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The Effect of Soy Protein on Post- Breast Cancer Surgery Pain

This study has been terminated.
(Difficulty with recruitment - few eligible for enrolment.)
National Cancer Institute (NCI)
Louise & Alan Edwards Foundation
McGill University
Information provided by (Responsible Party):
Dr. Yoram Shir, McGill University Health Center Identifier:
First received: January 12, 2010
Last updated: October 5, 2015
Last verified: October 2015
The incidence of chronic pain after breast cancer surgery (CPBCS) is high in women diagnosed with breast cancer. Similar to other chronic postoperative pain conditions, existing treatments for CPBCS do not always work. Adopting the concept of using pain relieving measures prior to surgery rather than after it, may lead to decreased postoperative pain levels. Soy has been shown to have pain-relieving properties and may reduce the risk for developing chronic post-surgical pain. The purpose of this study is to determine the effects of adding soy protein to the diet before surgery on the development of chronic pain.

Condition Intervention Phase
Chronic Disease
Breast Cancer
Dietary Supplement: Isolated soy protein
Dietary Supplement: Isolated milk protein
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
Official Title: Soy-rich Diet for Preventing Chronic Pain After Breast Cancer Surgery

Resource links provided by NLM:

Further study details as provided by McGill University Health Center:

Primary Outcome Measures:
  • Number of women in both arms with any pain of any type in operated breast or its vicinity [ Time Frame: 12 months post-surgery ]

Secondary Outcome Measures:
  • Pain intensity (acute) [ Time Frame: Up to 7 days post-surgery ]
  • Pain intensity (chronic) [ Time Frame: Up to 12 months post-surgery ]
  • Analgesic medication use [ Time Frame: Up to 12 months post-surgery ]
  • Pain quality [ Time Frame: Up to 12 months post-surgery ]
  • Anxiety and Depression [ Time Frame: Up to 12 months post-surgery ]
  • Disability [ Time Frame: Up to 12 months post-surgery ]
  • Adverse events [ Time Frame: 2 weeks during dietary supplementation ]
  • Childhood and adolescence consumption of soy [ Time Frame: Baseline ]
  • Adverse events [ Time Frame: Up to 12 months post-surgery ]

Enrollment: 6
Study Start Date: March 2010
Study Completion Date: May 2013
Primary Completion Date: May 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Soy protein Dietary Supplement: Isolated soy protein
30-50g of protein powder daily for 2 weeks.
Other Names:
  • PRO-FAM 873
  • Code #066873
Placebo Comparator: Milk protein Dietary Supplement: Isolated milk protein
30-50g of protein powder daily for 2 weeks.
Other Name: PRODIET 85

Detailed Description:

Preclinical studies indicate that soy consumption suppresses the development of pain behavior and hyperalgesia following nerve injury. The pain-suppressing properties of soy protein have been shown to be predominately the result of soy pre-operative consumption.

This is a randomized, double blind, placebo-controlled clinical trial for women diagnosed with breast cancer and scheduled to undergo breast cancer surgery. The trial will comprise two phases: 1. A 2-week preoperative dietary manipulation phase, and 2. A one-year postoperative follow up period. In the first phase eligible candidates will undergo a basic dietary evaluation followed by stratification into 4 study groups, based on their pre-vs. postmenopausal status and the planned type of surgery, i.e., formal mastectomy vs. breast-conserving surgery. Women in each group will be randomized to receive either powdered soy protein in the experimental group or milk protein in the control group. During the second, post-surgical phase women will resume their normal diet. If shown to be beneficial, this simple dietary manipulation may prevent one of the most severe sequelae of breast cancer.


Ages Eligible for Study:   21 Years to 99 Years   (Adult, Senior)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Women diagnosed with breast cancer and scheduled for elective breast cancer surgery (excluding breast biopsy) with axillary lymph node dissection (total and/or sentinel node excision).
  • Women who are 21 years or older.

Exclusion Criteria:

  • History of significant heart, gastro-intestinal, liver or kidney disease.
  • Use of the anticoagulant, warfarin or Coumadin.
  • Malabsorption of any kind.
  • Diagnosed lactase deficiency.
  • Known allergy to any of the tested dietary products.
  • Basic daily consumption of soy protein in quantities exceeding 10 g/day.
  • Women who are strict vegetarians (i.e. no animal derived dietary sources).
  • The use of the following narcotics or adjuvant pharmacotherapy: opioids, anticonvulsants, antidepressants and steroids (except antidepressant use specifically for depression).
  • Tumour size (if known) > 3cm(i.e. size before pre-operative chemotherapy, if administered).
  • Locally advanced breast cancer.
  • Inflammatory breast cancer.
  • Paget's disease of the breast with palpable mass.
  • Suspected metastasis.
  • Suspected micrometastasis.
  • Previous breast surgery of any kind (except needle biopsy).
  • The need for bilateral breast surgery.
  • The existence of other known cancer, including metastasis, either in the other breast or elsewhere.
  • Previous or current endocrine cancer therapy (e.g. selective estrogen receptor modulators, aromatase inhibitor).
  • Body mass index (BMI) > 35.
  Contacts and Locations
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Please refer to this study by its identifier: NCT01047774

Canada, Quebec
Royal Victoria Hospital
Montreal, Quebec, Canada, H3A 1A1
McGill University Health Centre
Montreal, Quebec, Canada, H3G 1A4
Jewish General Hospital
Montreal, Quebec, Canada, H3T 1E2
St. Mary's Hospital Center
Montreal, Quebec, Canada, H3T 1M5
Sponsors and Collaborators
Dr. Yoram Shir
National Cancer Institute (NCI)
Louise & Alan Edwards Foundation
McGill University
Principal Investigator: Yoram Shir, MD McGill University Health Center
  More Information

Responsible Party: Dr. Yoram Shir, Doctor, McGill University Health Center Identifier: NCT01047774     History of Changes
Other Study ID Numbers: A02-M102-07A
5R21CA125873-02 ( US NIH Grant/Contract Award Number )
Study First Received: January 12, 2010
Last Updated: October 5, 2015

Keywords provided by McGill University Health Center:
soy protein

Additional relevant MeSH terms:
Breast Neoplasms
Chronic Disease
Neoplasms by Site
Breast Diseases
Skin Diseases
Disease Attributes
Pathologic Processes processed this record on April 24, 2017