Tuberculosis May Cause Spontaneous Tumor Regression in IPF Patients with Lung Cancer, Case Report Suggests
In very rare cases, a tuberculosis infection in people with idiopathic pulmonary fibrosis (IPF) and lung cancer may help activate the immune system and induce a spontaneous cancer remission, a case report suggests.
While the patient in the study achieved complete cancer regression after treatment with standard first-line chemotherapy for lung cancer — gemcitabine plus cisplatin — the researchers said they do not believe chemotherapy was the sole cause of such a dramatic regression.
The study, “Complete regression of pulmonary squamous carcinoma in IPF following gemcitabine plus cisplatin: a case report and literature review,” was published in the journal BMC Pulmonary Medicine.
People with IPF often have co-existing conditions that negatively affect their quality of life and survival rates. One of the most common is lung cancer, but the management of IPF patients with this cancer remains controversial, as most treatment approaches — like surgery, radiation therapy, and chemotherapy — may exacerbate IPF and increase the risk of death.
Researchers now presented the case of a 67-year-old man with IPF and squamous lung cancer whose tumor regressed completely after chemotherapy. However, after the cancer disappeared, a tuberculosis infection became evident, and the team suggested that the infection was the likely cause of cancer regression.
The man came to the hospital after starting to cough up blood. He had been experiencing cough and mild shortness of breath for the past seven years. He was a light smoker, and had been diagnosed with diabetes more than 13 years ago.
Imaging exams of the lung demonstrated usual interstitial pneumonia (UIP) pattern, widening of the airways (bronchiectasis), and a honeycombing pattern, which represents enlarged airspaces with thickened walls. All of these circumstances led to a diagnosis of IPF.
Chest imaging also showed a nodule suggestive of tuberculosis infection in the right upper lobe, and a single 25-millimeter mass in the right lower lobe, which was later confirmed as squamous lung cancer through a biopsy.
Because surgery and radiation therapy may exacerbate IPF, the patient was treated with gemcitabine plus cisplatin chemotherapy — considered the standard first-line treatment for patients with advanced squamous lung cancer or for whom surgery is not an option.
After six cycles of this chemo combination, the man received an additional three cycles of gemcitabine maintenance therapy. But right after the first cycle, the cancer in the right lower lobe had completely disappeared, and remained undetectable for at least two years. IPF also was stable.
Nonetheless, a follow-up chest scan showed that the upper lung nodule had increased in size, and a bronchoalveolar lavage sample tested positive for tuberculosis. The patient received anti-tuberculosis treatment, after which the nodule’s size decreased.
While this chemotherapy regimen may improve quality of life and extend survival in lung cancer patients, only a small number of patients benefit from it, and survival is low even for those who do. Also, the fact that the cancer completely disappeared after two cycles of chemotherapy “is extremely rare and beyond our expectations,” researchers wrote, adding that they “do not believe that gemcitabine plus cisplatin led to complete disappearance of squamous lung cancer.”
Instead, the team believes that a spontaneous regression should be considered, and that this regression likely was caused by immune activation in response to the tuberculosis infection. In fact, a study has pointed toward better survival rates in lung cancer patients with tuberculosis than in patients without tuberculosis.
“Based on the above, one possible explanation for our case is that co-existing [tuberculosis] stimulates the immune system and shifts towards … immune responses against tumors,” researchers concluded. “Additional research is needed to explain the possible mechanisms by which this occurs.”