Case Report: A Rare Case of Metachronous Multiple Primary Lung Cancers in a Patient With Successful Management by Switching From Anti-PD-1 Therapy to Anti-PD-L1 Therapy

Long-term survival of dogs with stage 4 oral malignant melanoma treated with anti-canine PD-1 therapeutic antibody: A follow-up case report

A monoclonal antibody targeting programmed cell death-1 (PD-1) is one of the most promising treatments for human cancers. Clinical studies in humans demonstrated that the anti-PD-1 antibody provides a long-lasting tumour response. Previously, we established an anti-canine PD-1 therapeutic antibody (ca-4F12-E6), and the pilot clinical study demonstrated that the antibody was effective in dogs with oral malignant melanoma (OMM). However, two OMM cases were still undergoing treatment when the pilot study was published. Here, we describe the long-term follow-up of those two cases. Although both cases showed long-term survival with complete response (CR), the tumour response differed; the effect onset was slow in one case and a durable response was observed in the second case even after treatment discontinuation. Secondary malignant tumours occurred during treatment in both cases. This follow-up study revealed that ca-4F12-E6 maintains CR in dogs for more than 1 year. In addition, the pattern of tumour response was unique compared to conventional therapy. These results indicate that new evaluation criteria for tumour response may be necessary for immunotherapy in veterinary medicine. Long-term follow-up is necessary regardless of the short-term treatment responsiveness.

Recent Advances in the Diagnosis and Management of Multiple Primary Lung Cancer

With the wide application of computed tomography in lung cancer screening, the incidence of multiple primary lung cancer (MPLC) has been increasingly reported. Despite the established criteria, the differentiation between MPLC and intrapulmonary metastasis remains challenging. Although histologic features are helpful in some circumstances, a molecular analysis is often needed. The application of next-generation sequencing could aid in distinguishing MPLCs from intrapulmonary metastasis, decreasing ambiguity. For MPLC management, surgery with lobectomy is the main operation method. Limited resection does not appear to negatively affect survival, and it is a reasonable alternative. Stereotactic ablative radiotherapy (SABR) has become a standard of care for patients refusing surgery or for those with medically inoperable early-stage lung cancer. However, the efficacy of SABR in MPLC management could only be found in retrospective series. Other local ablation techniques are an emerging alternative for the control of residual lesions. Furthermore, systemic therapies, such as targeted therapy for oncogene-addicted patients, and immunotherapy have shown promising results in MPLC management after resection. In this paper, the recent advances in the diagnosis and management of MPLC are reviewed.