Cancer-related pain is complex and multidimensional but is mostly managed using drug therapy. There is increasing recognition of the need for non-drug approaches and TENS may have a significant role to play. Only one new study met eligibility criteria for this review update, making at total of three included studies. TENS was given to 15 participants in one study, 41 participants in the other and 24 participants in the most recently included study. The newly included study suggested TENS might improve cancer bone pain on movement, but as a pilot study it was not designed to determine the impact of TENS on pain. The two studies in the previous review did not show that TENS significantly improved cancer pain. One study did not have sufficient participants to determine whether or not TENS had an effect. TENS was well tolerated in all three studies. There were significant differences in participants, treatments, procedures and symptom measurement tools used in the studies. In two of the studies some participants were able to identify when they received active TENS and when they received placebo. Consequently, there is insufficient evidence to judge whether TENS should be used in adults with cancer-related pain. Further research using well designed clinical trials is needed to improve knowledge in this field.
Despite the one additional RCT, the results of this updated systematic review remain inconclusive due to a lack of suitable RCTs. Large multi-centre RCTs are required to assess the value of TENS in the management of cancer-related pain in adults.
Cancer-related pain is complex and multi-dimensional but the mainstay of cancer pain management has predominantly used a biomedical approach. There is a need for non-pharmacological and innovative approaches. Transcutaneous Electric Nerve Stimulation (TENS) may have a role in pain management but the effectiveness of TENS is currently unknown. This is an update of the original review published in Issue 3, 2008.
The aim of this systematic review was to determine the effectiveness of TENS for cancer-related pain in adults.
The initial review searched The Cochrane Library, MEDLINE, EMBASE, CINAHL, PsychINFO, AMED and PEDRO databases in April 2008. We performed an updated search of CENTRAL, MEDLINE, EMBASE, CINAHL and PEDRO databases in November 2011.
We included only randomised controlled trials (RCTS) investigating the use of TENS for the management of cancer-related pain in adults.
The search strategy identified a further two studies for possible inclusion. One of the review authors screened each abstract using a study eligibility tool. Where eligibility could not be determined, a second author assessed the full paper. One author used a standardised data extraction sheet to collect information on the studies and independently assess the quality of the studies using the validated five-point Oxford Quality Scale. The small sample sizes and differences in patient study populations of the three included studies (two from the original review and a third included in this update) prevented meta-analysis. For the original review the search strategy identified 37 possible published studies; we divided these between two pairs of review authors who decided on study selection; all four review authors discussed and agreed final scores.
Only one additional RCT met the eligibility criteria (24 participants) for this updated review. Although this was a feasibility study, not designed to investigate intervention effect, it suggested that TENS may improve bone pain on movement in a cancer population. The initial review identified two RCTs (64 participants) therefore this review now includes a total of three RCTs (88 participants). These studies were heterogenous with respect to study population, sample size, study design, methodological quality, mode of TENS, treatment duration, method of administration and outcome measures used. In one RCT, there were no significant differences between TENS and placebo in women with chronic pain secondary to breast cancer treatment. In the other RCT, there were no significant differences between acupuncture-type TENS and sham in palliative care patients; this study was underpowered.