INTRODUCTION

Cancer pain is a difficult problem for clinicians because analgesic drugs do not always relieve pain completely (1, 2). For a decade, auricular acupuncture has been part of the treatment of pain (3, 4). Its recent use for the treatment of cancer pain, as a complementary treatment to analgesic drugs when these are not sufficient is recent and must be evaluated.

We report here the results of auricular acupuncture in a series of twenty patients with cancer pain treated between July and November 1997 in the Service of Analgesia of Institut Gustave Roussy, a large cancer center in France.

PATIENTS AND METHODS

Twenty patients with cancer, still experiencing pain after a treatment with analgesics, were included in the study. Pain intensity was evaluated by a nurse on a Visual Analogue Scale (V.A.S.) both before the initiation of the drug treatment (initial D) and after at least one month of a stable treatment with World Health Organization level 2 or 3 analgesics (at DO). This stable analgesic treatment was continued after auriculotherapy. They all had to have a pain intensity of 30 mm or more at DO.

An electric chart of the ear was obtained for each patient by measuring the electrical potential of the skin at the points suspected to be pain's projected points on the ear, according to the clinical symptoms of the patient. Auriculotherapy treatment was then performed by inserting single-use sterile needles at points where an electrical potentiel had been detected.

A leaflet was given to each patient including an image of the ear where the points of insertion of each needle had been marked for him to report the dates when needles fell. This leaflet was also used to record the weekly consumption of analgesics used and the pain intensity measured weekly according to the VAS.

Pain intensity was evaluated by a nurse around D60 after auriculotherapy i.e. when the patients came back to the clinic for routine follow-up of their cancer.

The effectiveness of auricular acupuncture was measured by the difference in pain intensity evaluated on the VAS at D60 and at DO, and tested by a t-test. We also measured the correlation between pain intensity at DO and the value of the ear's skin electrical potential at the main auricular projection point of the pain (Spearman coefficient).

RESULTS

Twenty patients were treated by auricular acupuncture between May and September 1997. Their average age was 54.3 with a standard deviation of 11.3.

There were 11 cases of post-mastectomy brachial plexitis, 3 cases of post surgical trigeminus neuralgia, and 1 case each of vesical plexitis, neuropathic lingual neuralgia, superficial cervical plexus neuroma, right sinus neoplasm, cerebellar medulloblastoma with diffuse pain, and lingual neoplasm with radicular pain. The general health status on OMS scale was on "0" for 16 patients and on "1" for the four others. Pain appeared at time of neoplasm diagnosis for four patients and for the other 16 patients pain started after surgical treatment.

The average time between initial analgesic treatment (initial D) and auricular acupuncture (DO) was 4 months, with a range of 1 to 5 months. All the patients were treated with OMS level 2 analgesics and 2 patients received additionally morphin sulfates. At DO, the analgesic treatment had been stable for an average of 1.4 months (range 0.7 to 2.3 months).

The initial pain as measured on the VAS was on average 76 mm (SD 16). At DO, pain intensity and the value of the ear's electrical potential at the main auricular projection point of the pain were correlated (r = 0.9, p < 10 ^-4). Needles used for auricular acupuncture felled between 5 and 35 days after auricular acupuncture.

There was no significant variation between the initial pain and the pain at DO: the average at DO was 74 mm, and the variation between D initial and DO was on average 2 mm (standard error = 2, p = 0.16). Pain intensity decreased or remained stable after auricular acupuncture for every patient. The average pain intensity decreased by 33 mm (standard error = 5, p < 10 ^-5) between DO and D60.

It is interesting to note that the improvement was not limited to the diminution of the pain. Patients improved after auricular acupuncture also said that they felt better and some felt well enough to suggest interrupting their analgesic treatment.

DISCUSSION

The analgesic action of auricular acupuncture observed in this study, associated with the knowledge already acquired on this medical discipline (5-10, 12) encouraged us to design a randomized controlled trial with double placebo and independent observer.

The protocol of this trial has been written and accepted by the Official Authorities. Its main objective is to evaluate the effectiveness of auricular acupuncture in the treatment of intensive and persistent neoplasm pains.

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