[Therapy-induced tumor regression and regression grading in lung cancer]

[Neoadjuvant therapy for resectable non-small cell lung cancer]

Treatment perspectives for non-small cell lung cancer (NSCLC) have been significantly expanded by the integration of immune checkpoint inhibitors into multimodal therapy concepts. Currently, combined, immune checkpoint-inhibitor-based therapy concepts are also advancing into early, resectable stages of NSCLC. Neoadjuvant and perioperative chemoimmunotherapy opened up a promising new preoperative treatment approach, but also raises some new questions and challenges. With the expanded perioperative treatment options and the perspective on a further improvement in the absence of recurrence after tumor resection, there is push towards comprehensively collecting therapy-relevant findings for imaging, molecular and histopathological diagnostics at an early stage. All patients with lung carcinoma, regardless of the therapy intention, should be presented to an interdisciplinary tumor board with thoracic oncological expertise. This is regularly given in certified lung cancer centers.A standardized procedure contributes to optimized pre-therapeutic diagnostics and facilitates coordination for the best possible multimodal approach in the interdisciplinary tumor board. In the case of centrally located resectable tumors, for example, neoadjuvant treatment increases the chances of a procedure that is as parenchymal sparing as possible. Some questions cannot yet be answered conclusively. Perioperative systemic therapy with molecular-targeted and immune checkpoint inhibitors is the subject of numerous ongoing studies. The considerable dynamics in newly approved therapies and the development of perioperative therapy concepts require continuous adaptation of diagnostic algorithms and standards. Integration into standard pre-surgical routine makes rapid classification of the relevant findings as well as close coordination between the diagnostic and interventional disciplines essential.

[Pathological-anatomical diagnosis according to the German lung cancer guideline 2018]

The German S3-guideline on prevention, diagnosis, therapy and follow-up of lung cancer, published in February 2018, expands on the 2010 guideline to include a total of 19 recommendations and statements regarding the "processing of lung resection specimens (tumor resection specimens)", "processing of lymph nodes", "histo-pathological typing and immunophenotype", "extent of tumor growth in resection specimens", "resection margins" or "R-classification", "grade of malignancy (grading)", "regression grading" as well as the "examination of molecular targets". The statements regarding the analysis of molecular targets result from the diagnostic requirements of the current targeted therapy of advanced lung cancer. At the same time, a pathological-anatomical diagnosis according to the current S3-guideline fulfills all corresponding requirements in certified lung cancer centers.

Novel stereotactic body radiation therapy (SBRT)-based partial tumor irradiation targeting hypoxic segment of bulky tumors (SBRT-PATHY): improvement of the radiotherapy outcome by exploiting the bystander and abscopal effects

Background

Despite the advances in oncology, patients with bulky tumors have worse prognosis and often receive only palliative treatments. Bulky disease represents an important challenging obstacle for all currently available radical treatment options including conventional radiotherapy. The purpose of this study was to assess a retrospective outcome on the use of a newly developed unconventional stereotactic body radiation therapy (SBRT) for PArtial Tumor irradiation of unresectable bulky tumors targeting exclusively their HYpoxic segment (SBRT-PATHY) that exploits the non-targeted effects of radiotherapy: bystander effects (local) and the abscopal effects (distant).

Materials and methods

Twenty-three patients with bulky tumors received partial bulky irradiation in order to induce the local non-targeted effect of radiation (bystander effect). The hypoxic tumor segment, called the bystander tumor volume (BTV), was defined using PET and contrast-enhanced CT, as a hypovascularized-hypometabolic junctional zone between the central necrotic and peripheral hypervascularized-hypermetabolic tumor segment. Based on tumor site and volume, the BTV was irradiated with 1–3 fractions of 10–12 Gy prescribed to 70% isodose-line. The pathologic lymph nodes and metastases were not irradiated in order to assess the distant non-targeted effects of radiation (abscopal effect). No patient received any systemic therapy.

Results

At the time of analysis, with median follow-up of 9.4 months (range: 4–20), 87% of patients remained progression-free. The bystander and abscopal response rates were 96 and 52%, respectively. Median shrinkage of partially irradiated bulky tumor expressing intensity of the bystander effect was 70% (range 30–100%), whereas for the non-irradiated metastases (intensity of the abscopal effect), it was 50% (range 30–100%). No patient experienced acute or late toxicity of any grade.

Conclusions

SBRT-PATHY showed very inspiring results on exploitation of the radiation-hypoxia-induced non-targeted effects that need to be confirmed through our ongoing prospective trial.

Present study has been retrospectively registered by the local ethic committee under study number A 26/18.

Patient-derived tumor xenografts of lung squamous cell carcinoma alter long non-coding RNA profile but not responsiveness to cisplatin

Lung squamous cell carcinoma (LSCC), the second most common type of lung cancer, has received limited attention. Patient-derived tumor xenografts (PDTXs) are useful preclinical models to reproduce the diverse heterogeneity of cancer, but it is important to identify potential variations during their establishment. A total of 18 PDTXs were established from 37 the surgical specimens and 16 were serially passaged to third generation. Second- and third-generation xenografts had a faster growth rate in mice. The tumor implantation success rate was associated with poorer differentiation, larger tumor volume and higher expression of Ki-67. The xenografts largely retained histological and key immunophenotypic features (including p53, p63, cytokeratin5/6, and E-cadherin). However, increased Ki-67 expression was identified in partial xenografts. Long non-coding RNA (lncRNA) and mRNA expression in third-generation xenografts differed from that of matched primary tumors. Gene Ontology and pathway analysis showed that mRNAs involved in cell cycle, and metabolism regulation were generally upregulated in xenografts, while those associated with immune responses were typically downregulated. Furthermore, the responses of xenografts to cisplatin were consistent with clinical outcome. In the present study, PDTXs of SCC were successfully established, and closely resembled their original tumor regarding their immunophenotype and response to cisplatin. Overall, PDTXS of LSCC altered the lncRNA profile and increased the proliferative activity of cancer cells, whilst retaining responsiveness to cisplatin.