Abstract
Background: Immunotherapy is growing its popularity due to fewer side effects and better drug tolerance in cancer management and is replacing chemotherapy. Because these treatments are new and immunotherapy has different side effects, physicians are not very well versed with them. Most of the side effects of immunotherapy are because of cytokine surge hence the treatment is different. We are discussing a case of severe hypothyroidism secondary to durvalumab that is associated with immune-mediated endocrinopathies.
Case: 70-years old female with a medical history of lung cancer (dx 2015, s/p left upper lobectomy, recurrent poorly differentiated squamous cell carcinoma, left lower lobe, diffusely positive for p40 while negative for TTF-1 in April 2019 s/p chemo and radiotherapy), hyperlipidemia, COPD and hypertension comes to the clinic with swelling of the face, shortness of breath, fatigue and weight gain. The patient was started on durvalumab on 08/2019 for 12 months as per NCCN guidelines for adjuvant treatment of her (T3N0M0) Stage 2b lung cancer after chemotherapy and radiation treatment. Physical examination was positive for abdominal distension, swelling of the face, and bilateral lower extremities, decreased breath sounds in bilateral lower lobes. The patient was started on furosemide 20mg OD and started feeling better for a few days before the symptoms worsened. We checked her thyroid function test as she had symptoms of hypothyroidism, labs showed TSH:>49, T3:26.9, and T4:0.70. The patient was diagnosed with durvalumab induced severe hypothyroidism and started on 50MG levothyroxine OD. The patient is feeling better after starting levothyroxine and the swelling and symptoms have reduced with TSH trending down. The patient continued taking durvalumab as per NCCN guidelines.
Discussion: This case is a rare side effect of immunotherapy. Treatment involves the replacement of thyroid hormone. It’s imperative to check thyroid function tests at least every 3 months while the patient is on durvalumab. Side effect profile of immunotherapy is mostly immune-mediated pneumonitis, colitis, hepatitis, and endocrinopathies. And these side effects are treated with steroids. Whereas chemotherapy mostly causes side effects by infections due to immunosuppression and treated by antibiotics and GCSF agents.
Conclusion: Our patient with recurrent squamous cell lung cancer developed hypothyroidism secondary to durvalumab.
