Pilot Study to Evaluate the Effect of Aromatase Inhibitor Therapy on Pain Threshold in Breast Cancer Patients

University of Michigan Rogel Cancer Center50 enrolled

Overview

Postmenopausal women who have hormone receptor positive breast cancer are typically treated with aromatase inhibitor medications, which substantially decrease the amount of estrogen produced by their bodies. These medications are fairly well tolerated, but can cause aches and pains which can be quite severe in some cases. People experience pain differently. Estrogen appears to play a role in how we experience pain. Therefore, decreasing estrogen levels may lead to more pain in some women than others. The goal of this study is to evaluate perception of pain in women with breast cancer, and to determine if differences in pain perception lead to more aches and pains in some women treated with aromatase inhibitors. In this study, we plan to enroll 55 women with breast cancer who are starting treatment with an aromatase inhibitor. Participants will undergo testing to evaluate their perception of pain, and will also complete a set of questionnaires. Testing will be conducted before starting aromatase inhibitor therapy, as well as after 3 and 6 months of therapy. We will investigate whether pre-existing differences in pain perception lead to different amounts of pain during aromatase inhibitor therapy.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Breast Cancer Pain Arthralgia

Interventions

Eligibility

Sex: FEMALEMin age: 21 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Female gender * Postmenopausal, age 21 or greater * Stage 0-III estrogen receptor and/or progesterone receptor positive breast cancer who will be receiving a standard dose of letrozole, anastrozole, or exemestane * Performance status 0-2 * Willing to sign the consent form Exclusion Criteria: * Average pain \>=8/10 over the past 24 hours * Peripheral sensory neuropathy grade 2 or higher * Personal history of schizophrenia, or suicidal ideation or attempt within the past 2 years * Thumbnail abnormalities on either hand that are likely to alter pain perception during testing

Outcomes

Primary Outcomes

Mean Pain50 Assessed at Baseline, 3 Months and 6 Months

Patients rated the intensity of each pressure sensation using a 0 to 100 numerical rating scale (0 = no pain, 100 = worst pain imaginable). Pain50 was defined as the amount of applied pressure in kilograms per square centimeter that evoked a pain intensity rating of 50 out of 100. Pain50 was assessed at baseline, 3 months, and 6 months. Change in Pain50 with estrogen depletion was determined.

Time frame: Baseline, 3 months, 6 months

Secondary Outcomes

Mean Conditioned Pain Modulation Assessed at Baseline, 3 Months, and 6 Months

To assess conditioned pain modulation, pressure equivalent to the patient's Pain50 was applied to the non-dominant thumbnail for 30 seconds (test stimulus), and the patient rated the intensity of the pressure on a 0-100 pain scale at 10 second intervals. Ten minutes later pressure (conditioning stimulus) was continuously applied to the dominant thumbnail for 60 seconds at the same Pain50 intensity. After 30 seconds, the test stimulus was again applied to the non-dominant thumbnail for 30 seconds and the patient rated the intensity every 10 seconds. Conditioned pain modulation magnitude was calculated as the difference (second minus first) in the mean of the 3 pain ratings to the test stimulus applied prior to and during the conditioning stimulus. Conditioned pain modulation was assessed at baseline, 3 months, and 6 months. Change over that time period was assessed. Higher conditioned pain modulation values indicate less efficient conditioned pain modulation.