Gemcitabine-induced myopathy

There have been few studies on muscle injury caused by cytotoxic agents used in cancer. In particular, only four cases of muscle manifestations have been reported in patients who received gemcitabine as single chemotherapy without adjuvant radiotherapy. In only one of these observations gemcitabine was considered to be the causative agent.

We report the case of a patient without comorbidity treated with gemcitabine monotherapy for 2 months for pancreatic adenocarcinoma, who developed a proximal motor deficiency of the lower limbs and myolysis (creatinine kinase 1858 IU/L) associated with an erythema of both thighs.

Muscle MRI revealed the presence of edema on both the quadriceps muscles. A muscle biopsy showed post-necrotic regeneration and significant vascular proliferation. Only three small inflammatory infiltrates were observed, while expression of the major histocompatibility complex class I in muscle fibers was normal. There was no recurrence of cancer, anti-TIF-1γ antibodies tested negative, and discontinuation of gemcitabine, without further treatment, resulted in complete disappearance of symptoms.

The present observation suggests that gemcitabine monotherapy without adjuvant radiotherapy can cause myopathy through vascular lesions, a mechanism which also underlies the more common side effects of this treatment. These findings have obvious therapeutic implications.