Efficacy of Myofascial Pain Syndrome Treatment in Patients With Cancer in Palliative Care

Palliative Care is active holistic care offered to people who are in intense suffering related to their health, resulting from a serious life-threatening illness, with a focus on improving the quality of life. Among the symptoms that cause suffering, physical pain has a prominent role in terms of prevalence and impact on well-being, especially in the subgroup of patients with terminal cancer. Myofascial Pain Syndrome may be one of the components of pain in cancer patients in palliative care. However, the literature is scarce in defining the prevalence of this condition in this population, and there is no evidence of the benefit of needling treatment with 1% lidocaine in these patients until now. The objectives of this study are to determinate the prevalence of myofascial pain syndrome and to evaluate the effectiveness of myofascial pain treatment with 1% lidocaine injection in reducing pain in palliative cancer patients, comparing it with a control group in usual care.

This is a clinical trial designed as a comparative, randomized, single-blinded intervention study. Patients will be recruited from wards and radiotherapy sector of the Ribeirão Preto Clinical Hospital - Ribeirão Preto Medical School, University of São Paulo (FMRP-USP). Initially, patients aged 50 years or older with cancer in palliative care will be evaluated to assess the prevalence of myofascial pain syndrome using Travel and Simons' diagnostic criteria and for the following variables: demographic characteristics, functional status (Palliative Performance Scale), pain intensity (visual analog scale and pain threshold measurement with a pressure gauge), prognostic score (Palliative Prognosis Score), depression and anxiety (Hospital Anxiety and Depression Scale), quality of life (European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 15 PAL) and analgesic drugs in use. The participants that (1) accomplish the Travel and Simons' diagnostic criteria for myofascial pain syndrome, (2) have performance status on the Karnofsky scale of 30 or more, and (3) have pain intensity on visual analog scale of 5 or more will be randomized for the clinical trial. The sample size calculation resulted in 15 participants for each group, totaling a sample composed of 30 patients. The intervention group will be submitted to the trigger point injection procedure with 1% lidocaine, and the control group will receive usual care, defined as the treatment for pain prescribed by their assistant doctors. Both groups will be reevaluated after 72 hours and 1 week after the procedure. In the analysis statistics, chi-square test (or Fisher's exact test) will be used to evaluate categorical variables. For the comparison between the groups at each moment (before and after intervention) will be used the linear mixed effects model. The significance level established was \<0.05. SAS Statistical Software (version 9.3; SAS Institute, Inc. Cary , NC) will be used for the analysis.

Eligibility Criteria:
Inclusion Criteria:

* Participants that

  1. accomplish the Travel and Simons' diagnostic criteria for myofascial pain syndrome,
  2. have pain intensity on visual analog scale of 5 or more,
  3. have performance status on the Karnofsky Performance Status scale of 30 or more.

Exclusion Criteria:

* Use of high dose anticoagulants (RNI above the therapeutic range);
* Patients with hemorrhagic diathesis;
* Patients with moderate to severe dementia syndrome;
* Patients with diagnosis of acute confusional state during the follow-up;
* Occurrence of clinical complication or intervention that could compromise the reevaluation of pain in the following days (for example, undergoing a surgical procedure or nerve block) or death.