Current and emerging treatment options for lung cancer in patients with pre-existing connective tissue disease.

An association between connective tissue disease (CTD) and lung cancer has been claimed in accumulating studies. However, the management of lung cancer with CTD is challenging because the pre-existing CTDs have proved to be significant risk factors for treatment-related toxicity, resulting in poor survival. In this review, we summarize the available information related to the treatment for lung cancer with CTD, discuss risk factors for treatment-related toxicities and management recommendations, which attempts to approach lung cancer with comorbid CTD systematically. Preliminary data show that: i) limited studies have focused on the effect of traditional therapeutic modalities, such as surgical treatment and chemotherapy; ii) with the development of the modern radiation techniques, radiotherapy would be well tolerated in this challenging clinical situation, but a cautious decision should be made for patients with CTD associated interstitial lung disease (ILD); iii) for patients with inactive CTD, immunotherapy was shown to have excellent local control with acceptable toxicity; iv) little information is available on the effects of tyrosine kinase inhibitors because of acute exacerbation (AE) of ILD risks; v) antiangiogenic therapy might be useful in preventing the progression in both lung cancer and CTD without increasing the AE-ILD risk; vi) Nintedanib would be a potentially promising novel therapy since it has recently been developed with promising results for both lung cancer and CTD-ILD. Further large-scale, randomized, controlled studies are still required to develop better therapeutic management for patients with lung cancer and pre-existing CTD.