Definitive primary therapy in patients presenting with oligometastatic non-small cell lung cancer

Radiation Therapy for Oligometastatic Non-Small Cell Lung Cancer: Theory and Practice

Management paradigms for metastatic non-small cell lung cancer (mNSCLC) are evolving. Locally ablative therapies are now being increasingly integrated into combined-modality treatment strategies for mNSCLC patients with limited burdens of metastatic foci, termed oligometastases. Concurrently, techniques allowing for precise high-dose radiotherapy delivered over 1 to 5 total treatments, termed stereotactic body radiation therapy (SBRT) or stereotactic ablative radiation therapy (SABR), have emerged as a powerful means of noninvasive tumor ablation with broad patient candidacy. Strong rationale exists for ablative therapy in the setting of oligometastatic NSCLC, including patterns-of-failure analyses and data supporting local ablation of oligoprogressive disease for patients with oncogene-addicted mNSCLC treated with tyrosine kinase inhibitors. In this article, we examine the theoretical basis for ablation of oligometastatic NSCLC and review the growing clinical literature of mNSCLC patients treated with ablative radiation therapy.

Risk factors and management of oligometastatic non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is an aggressive malignancy with close to half of all patients presenting with metastatic disease. A proportion of these patients with limited metastatic disease, termed oligometastatic disease, have been shown to benefit from a definitive treatment approach. Synchronous and metachronous presentation of oligometastatic disease have prognostic significance, with current belief that metachronous disease is more favorable. Surgical excision of intracranial and extracranial oligometastatic disease has been shown to improve survival, especially in patients with lymph node-negative disease, adenocarcinoma histology and smaller thoracic tumors. Definitive radiation to sites of oligometastatic disease and initial thoracic disease has also been shown to have a similar impact on survival for both intracranial and extracranial disease. Recent studies have reported on the use of targeted agents combined with ablative doses of radiation in the oligometastatic setting with promising outcomes. In this review, we present the historical and current literature describing surgical and radiation treatment options for patients with oligometastatic NSCLC.

The Response, Outcome and Toxicity of Aggressive Palliative Thoracic Radiotherapy for Metastatic Non-Small Cell Lung Cancer Patients with Controlled Extrathoracic Diseases

Background and Purpose

For metastatic non-small cell lung cancer (NSCLC) patients with controlled extrathoracic disease after systemic treatment, stable or progressive primary lung lesions may cause respiratory symptoms and increase comorbidities. In the present study, we sought to investigate whether aggressive palliative thoracic radiotherapy (RT) can enhance local control and improve the survival for this subgroup of patients.

Materials and Methods

Between March 2006 and December 2014, 56 patients with metastatic NSCLC who had responsive or stable extrathoracic diseases after chemotherapy and/or molecular targets, and received thoracic RT for stable and progressive primary lung lesions were included. RT with a median dose of 55 Gy (range, 40–62 Gy) was administered in 1.8–2.5 Gy fractions to primary lung tumor and regional mediastinal lymph nodes using modern RT technique. Overall survival (OS) from diagnosis, and locoregional progression-free survival (LRPFS), and survival calculated from radiotherapy (OS-RT) were estimated using the Kaplan-Meier method.

Results

There were 37 men and 19 women with a median age of 60 years at diagnosis. The median interval from the diagnosis of metastatic disease to thoracic RT was 8 months. Following thoracic RT, 26 patients (46%) achieved complete or partial response (overall response rate, ORR). Patients with squamous cell carcinoma or poorly-differentiated carcinoma had a higher ORR than those with adenocarcinoma (63% vs. 34%, P = 0.034). EGFR mutations was closely associated with a better ORR (45% vs. 29%, P = 0.284). At a median follow-up time of 44 months, the median OS, LRPFS after RT, and OS-RT were 50 months, 15 months, and 18 months.

Conclusion

Radical palliative throractic RT is safe and might be beneficial for primary lung lesions of metastatic NSCLC patients with controlled extrathoracic diseases.

The evolving role of radiotherapy in treatment of oligometastatic NSCLC

Non-small cell lung cancer (NSCLC) patients with metastases limited in site and number, termed oligometastases, may represent a unique subpopulation of advanced NSCLC with improved prognosis. The optimal management of these patients remains unclear with the treatment approach currently undergoing a paradigm shift. The potential benefit of aggressive metastasis directed local treatment with surgery and/or radiotherapy (RT) in combination with systemic therapy is bolstered predominantly by retrospective analyses but also by a growing number of non-randomized prospective studies regarding the use of ablative RT techniques including stereotactic body radiotherapy (SBRT), alternatively termed stereotactic ablative radiotherapy (SABR), directed at the primary tumor (if present) and all metastatic sites. Long-term survival is possible in a subset of patients treated aggressively in this manner. The challenge for the clinical oncology community moving forward is appropriately selecting patients for this treatment approach based on clinical, imaging, and molecular features and increasing enrollment of patients to prospective clinical trials to more definitively determine the added benefit and appropriate timing of aggressive metastasis directed therapy in the oligometastatic setting.

Radical thoracic radiotherapy may provide favorable outcomes for stage IV non-small cell lung cancer

BACKGROUND

This study investigates the outcome of synchronous stage IV non-small cell lung cancer (NSCLC) patients who received radical thoracic radiotherapy (TRT).

METHODS

We retrospectively reviewed the charts of stage IV NSCLC patients treated with TRT between January 2007 and December 2011. Radiotherapy was considered radical if it was the primary therapy with non-symptom driven intent, or consolidation therapy after initial chemotherapy and the biologically equivalent dose ≥53 Gy halted disease progression. The patients' demographics, disease characteristics, and treatment parameters were uniformly collected.

RESULTS

Eighty-one patients were irradiated with radical intent, including 52% with more than five metastatic lesions. The minimum follow-up was 31.5 months for survivors. The median overall survival (OS) was 20.8 months, with three and four-year OS rates of 23% and 18%, respectively. The median progression-free survival (PFS) was 8.2 months, with one and two-year PFS rates of 23% and 9%, respectively. Partial response (PR) after TRT and administration of targeted therapy were predictive of longer OS. The factors associated with favorable PFS included earlier local tunor node stage, absence of concurrent chemotherapy, and post-TRT PR. No correlation was found between the number of metastatic lesions and survival outcome. Incidences of grade ≥2 toxicities in the lung and esophagus were 9% and 26%, respectively.

CONCLUSIONS

Radical TRT may result in advantageous outcomes for selected stage IV NSCLC patients, regardless of the number of metastatic foci. Patients who achieved post-TRT PR attained the best outcomes.

Accelerated radiotherapy and concurrent chemotherapy for patients with contralateral central or mediastinal lung cancer relapse after pneumonectomy

BACKGROUND

Treatment options are very limited for patients with lung cancer who experience contralateral central or mediastinal relapse following pneumonectomy. We present results of an accelerated salvage chemoradiotherapy regimen.

METHODS

Patients with localized contralateral central intrapulmonary or mediastinal relapse after pneumonectomy were offered combined chemoradiotherapy including concurrent weekly cisplatin (25 mg/m(2)) and accelerated radiotherapy [accelerated fractionated (AF), 60 Gy, 8×2 Gy per week] to reduce time for repopulation. Based on 4D-CT-planning, patients were irradiated using multifield intensity-modulated radiotherapy (IMRT) or helical tomotherapy.

RESULTS

Between 10/2011 and 12/2012, seven patients were treated. Initial stages were IIB/IIIA/IIIB: 3/1/3; histopathological subtypes scc/adeno/large cell: 4/1/2. Tumour relapses were located in mediastinal nodal stations in five patients with endobronchial tumour in three patients. The remaining patients had contralateral central tumour relapses. All patients received 60 Gy (AF), six patients received concurrent chemotherapy. Median dose to the remaining contralateral lung, esophagus, and spinal cord was 6.8 (3.3-11.4), 8.0 (5.1-15.5), and 7.6 (2.8-31.2) Gy, respectively. With a median follow-up of 29 [17-32] months, no esophageal or pulmonary toxicity exceeding grade 2 [Common terminology criteria for adverse events (CTC-AE) v. 3] was observed. Median survival was 17.2 months, local in-field control at 12 months 80%. Only two local recurrences were observed, both in combination with out-field metastases.

CONCLUSIONS

This intensified accelerated chemoradiotherapy schedule was safely applicable and offers a curative chance in these pretreated frail lung cancer patients.

The biology and treatment of oligometastatic cancer

Clinical reports of limited and treatable cancer metastases, a disease state that exists in a transitional zone between localized and widespread systemic disease, were noted on occasion historically and are now termed oligometastasis. The ramification of a diagnosis of oligometastasis is a change in treatment paradigm, i.e. if the primary cancer site (if still present) is controlled, or resected, and the metastatic sites are ablated (surgically or with radiation), a prolonged disease-free interval, and perhaps even cure, may be achieved. Contemporary molecular diagnostics are edging closer to being able to determine where an individual metastatic deposit is within the continuum of malignancy. Preclinical models are on the outset of laying the groundwork for understanding the oligometastatic state. Meanwhile, in the clinic, patients are increasingly being designated as having oligometastatic disease and being treated owing to improved diagnostic imaging, novel treatment options with the potential to provide either direct or bridging therapy, and progressively broad definitions of oligometastasis.

Definitive dose thoracic radiation therapy in oligometastatic non-small cell lung cancer: A hypothesis-generating study

PURPOSE

A subset of patients with minimal extrathoracic disease may benefit from aggressive primary tumor treatment. We report comparative outcomes in oligometastatic non-small cell lung cancer (NSCLC) treated with and without definitive, conventionally fractionated thoracic radiation therapy.

METHODS AND MATERIALS

We identified consecutive patients with stage IV NSCLC who had an Eastern Cooperative Oncology Group performance status ≤2 and ≤4 total sites of metastatic disease and who had been prescribed ≥50 Gy of thoracic radiation.

RESULTS

Twenty-nine patients with oligometastatic NSCLC were identified between January 2004 and August 2010. Median survival was 22 months from diagnosis. Four patients (14%) experienced pneumonitis greater than or equal to grade 3; 6 (21%) had esophagitis greater than or equal to grade 3. Local control was associated with improved survival (P = .02). In matched subset analysis, median survival was 9 months (P < .01) in patients who received chemotherapy alone. Median time to local failure was 18 versus 6 months (P = .01). On multivariable analysis, radiation (P < .01; odds ratio [OR], 0.33), fewer metastases (P < .01; OR, 2.14), and female sex (P < .01; OR, 0.41) were associated with improved survival.

CONCLUSIONS

Definitive dose radiation therapy may improve survival in a select subset of patients with minimal extrathoracic disease in whom local progression is of primary concern. Prospective trials are needed to further evaluate the role of local control in oligometastatic NSCLC.

To SABR or not to SABR? Indications and contraindications for stereotactic ablative radiotherapy in the treatment of early-stage, oligometastatic, or oligoprogressive non-small cell lung cancer

Stereotactic ablative radiotherapy (SABR) is a highly effective treatment for early-stage non-small cell lung cancer. Although direct comparisons from randomized trials are not available, rates of both primary tumor control and distant metastasis are similar between SABR and surgery. Overall survival is lower after SABR compared with surgery, largely reflecting that a primary selection criterion for SABR has been medical inoperability because of decreased cardiopulmonary function and other comorbidities that lead to decreased survival independent of non-small cell lung cancer. Survival outcomes between SABR and surgery are much more similar in propensity-matched cohorts. Newer potential indications for SABR include treatment of operable patients; of oligometastatic lung cancer, in which SABR has emerged as an alternative to metastasectomy; and of oligoprogressive lung cancer, an attractive concept especially as improved personalized systemic therapies emerge, and prospective trials are currently being conducted in these settings. Although toxicity in modern series is low, SABR is clearly capable of producing fatal complications, and understanding the risk factors and approaches for mitigating them has been emerging in recent years. Thus, appropriate patient selection is a vital, evolving, and controversial topic.