Continuum of somatosensory profiles in breast cancer survivors with and without pain, compared to healthy controls and patients with fibromyalgia.

CONTEXT: The prevalence of persistent pain among breast cancer survivors (BCS) is high, and it is unclear what distinguishes those with persistent pain from those without. Research suggests that differences in somatosensory function evaluated by quantitative sensory testing (QST) may be responsible.

OBJECTIVES: This study aimed to describe somatosensory profiles in terms of hyper- and hypoesthesia in BCS with and without persistent pain using reference data from healthy controls. Second, QST parameters of BCS with and without pain were compared with those of healthy controls (i.e., a negative control group) and patients with fibromyalgia (i.e., a positive control group).

METHODS: Participants (n = 128) were divided into four equal groups: healthy controls, BCS with persistent pain, BCS without persistent pain, and patients with fibromyalgia. Nine QST parameters were evaluated at the trunk and at a remote location. Somatosensory profiles were determined by Z-score transformation of QST data using normative data from healthy controls.

RESULTS: At the trunk, compared to healthy controls, BCS with persistent pain exhibited sensory aberrations across five out of seven QST parameters: pressure pain threshold, mechanical detection, and thermal thresholds. Pain-free BCS showed similar sensory aberrations across the four QST parameters compared to healthy controls: mechanical detection and thermal thresholds. Temporal summation and conditioned pain modulation were not significantly different between groups.

CONCLUSION: BCS with persistent pain exert aberrations in peripheral processing of nociceptive signals, heightened facilitation of nociceptive signals, and higher psychosocial burden when compared to pain-free BCS, healthy controls, and patients with fibromyalgia.

SIGNIFICANCE: This study investigates the somatosensory function of breast cancer survivors with and without persistent pain using quantitative sensory testing and two control group (i.e., patients with fibromyalgia and healthy controls). Our results indicate somatosensory aberrations within the peripheral, but not central pathways in breast cancer survivors with persistent pain. Our findings contribute to a better understanding of the somatosensory mechanisms underlying persistent pain, which may inform future interventions to prevent the development of persistent pain, and improve treatment modalities.