Psychophysical examination in patients with post-mastectomy pain

Chronic pain, lymphoedema, post-irradiation neuropathy and other symptoms are reported in as many as 75% of women following breast cancer treatment. This study examined pain and sensory abnormalities in women following breast cancer surgery. Sensory tests were carried out on operated and contralateral sides in 15 women with spontaneous pain and sensory abnormalities and 11 pain-free women. Testing included the VAS score of spontaneous pain, detection and pain threshold to thermal and mechanical stimuli, temporal summation to repetitive heat and pinprick stimuli, and assessment of skin blood flow during repetitive brush and pinprick stimulation. Sensory threshold to pinprick and thermal stimuli was significantly higher on the operated side in both groups while pressure pain threshold was significantly lower in pain patients on the operated side compared to the contralateral side. No side to side difference was seen in pressure pain threshold in the pain-free group. Evoked pain intensity to repetitive stimuli at 0.2 and 2.0 Hz was significantly higher on the operated side in pain patients compared to the control area while no such difference was seen in pain-free patients. Cutaneous blood flow measured by laser Doppler (flux) was significantly higher when the skin was tapped at 2.0 Hz on the operated side compared to contralaterally in pain patients, while no side to side difference was seen in pain-free patients. Pinprick-evoked pain was correlated to spontaneous pain but not to flux. Spontaneous pain was not correlated to flux. Sensitization seems to be a feature in breast cancer-operated women with pain, but not in pain-free women.