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ABSTRACT
Penile cancer is a rare malignant disease. Paclitaxel combined with platinum is often used as a first-line chemotherapeutic regimen for late-stage penile cancer, and there is no standard second-line treatment. Clinical trials of immunotherapy for penile cancer are ongoing. There are no reports on PD1 inhibitor treatment in metastatic penile carcinoma patients with MMR/MSI status heterogeneity. A 68-year-old patient was hospitalized with bilateral inguinal lymph node metastasis and local penile recurrence after penile cancer surgery. The lesion of the right inguinal lymph node showed a mismatch-repair-deficient (dMMR)/microsatellite instability-low (MSI-L) status. After 3 cycles of sintilimab (a PD1 inhibitor) combined with paclitaxel and cisplatin, the partial response of the tumor was evaluated. Subsequently, sintilimab monotherapy was used as maintenance treatment for 2 months. However, The lesion of local penile recurrence showed mismatch repair proficient (pMMR)/microsatellite stability (MSS) status by secondary biopsy when progressed rapidly. Interestingly, after continued treatment with sintilimab combined with gemcitabine, the patient achieved a partial response again. We should be aware of the importance of secondary biopsy for different lesions to confirm the heterogeneity of MMR/MSI status. For penile cancer patients with MMR/MSI status heterogeneity, PD1 inhibitors combined with chemotherapy are safe and effective. Due to oligometastatic lesion progression caused only by the heterogeneity of MMR/MSI status, PD1 inhibitor cross-line therapy can also be considered an appropriate treatment.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Consent for publication
Written informed consent was obtained from the patient for publication of this case report and any accompanying images.
Authors’ contributions
All authors contributed significantly to the manuscript and are in agreement with the content. YY-D wrote the manuscript in consultation with XL-Z. YZ and WL-L conducted data collection. WQ-H, LZ and JZ revised the manuscript and directed the research. All authors read and approved the final manuscript.
Abbreviations
| dMMR | = | mismatch-repair-deficient |
| pMMR | = | mismatch repair proficient |
| MSI | = | microsatellite instability |
| TMB | = | tumour mutational burden |
| PD-1 | = | programmed cell death protein 1 |