Research in interventional oncology: How sound is the evidence base?

INTRODUCTION

Interventional oncology (IO) is an essential component of cancer care, which has gained substantial recognition in recent years. The aim of this review is to evaluate the level of evidence supporting IO and its inclusion in cancer treatment guidelines.

METHODS

A literature search of the PubMed database was performed to identify publication numbers and types for IO treatments published between 2012 and 2022. Selected cancer treatment guidelines and recommendations were reviewed for their inclusion of IO treatments.

RESULTS

With 68%, the majority of studies on IO treatments are case reports while randomised controlled trials (RCTs) amount only to 7% of studies. Despite this, IO studies have generated sufficient data to support the inclusion of IO treatments in cancer treatment guidelines and recommendations. This was frequently based on large prospective patient cohorts that corresponded to 24% (20% non-randomised studies and 4% observational studies) of all analysed studies rather than RCTs.

CONCLUSION

The level of evidence underpinning IO, as well as inclusion of IO in treatment guidelines and recommendations have increased substantially in recent years, indicating the growing importance and acceptance of IO in cancer care. The difficulty in conducting RCTs in IO is mitigated by the observation that they are not necessary to achieve guideline-inclusion. Nevertheless, it is crucial to conduct well-designed research projects to further consolidate the position of IO in the field of oncology. This will ensure that IO continues to evolve and meet the needs of cancer patients worldwide.

Colorectal cancer with synchronous unresectable liver metastases: resecting the primary tumor improves survival

PURPOSE

The optimal treatment strategy of patients affected by colorectal cancer (CRC) with synchronous unresectable liver metastases (SULM) is at present undefined. It is not known if a palliative primary tumor resection followed by chemotherapy could have a survival benefit compared to upfront chemotherapy (CT). The aim of the study is to analyze the safety and effectiveness of both therapeutic strategies in a group of patients treated at one institution.

METHODS

A prospectively collected database was queried for patients affected by colorectal cancer with synchronous unresectable liver metastases between January 2004 and December 2018, defining and comparing 2 groups: patients treated by chemotherapy alone (group 1) vs patients who underwent primary tumor resection with or without a first line chemotherapy (group 2). The primary end point was Overall Survival (OS), estimated by the Kaplan-Meier method.

RESULTS

One hundred sixty-seven patients were included: 52 in group 1 and 115 in group 2, median follow-up 48 months (range 25-126). A difference of 14 months in overall survival was observed between group 2 compared to group 1 (28 vs 14 months respectively; p < 0.001). Furthermore, overall survival increased in patients who underwent liver metastases resection (p < 0.001) or percutaneous radiofrequency ablation after surgery (p < 0.001).

CONCLUSION

With the limits of a retrospective analysis, the study shows that surgical resection of the primary tumor has a significant impact on survival compared to chemotherapy alone. Randomized controlled trials are needed to confirm these data.

Consensus on management of metastatic colorectal cancer in Central America and the Caribbean: San José, Costa Rica, August 2016

Colorectal cancer (CRC) is the third most common cancer in men and the second most common in women worldwide. In Latin America and the Caribbean, it has a mortality of 56%. The median overall survival for patients with metastatic colorectal cancer (mCRC) is currently estimated as ~30 months, which has substantially improved through strategic changes in treatment and in the management of patients. As opposed to other metastatic cancers where first-line regimens are often determined, mCRC requires special attention because there is controversy in the possible combinations of the available drugs and the different periods of duration for each patient. Each combination must seek to be effective and to generate the minimum adverse effects as possible. Instead of giving the first-line regimen until the tumour progresses, treatment is often individualised. Furthermore, up to 60% of colorectal tumours are considered non-mutated or wild-type CRC. Not harbouring mutations in the RAS family of genes or mutations in the signalling pathways of the epidermal growth factor receptor causes a null response to anti-epidermal growth factor receptor antibody therapy, which implies even more complex considerations regarding its management. The primary objective of this consensus is to address the main scenarios of mCRC in order to warrant the most appropriate therapeutic intervention for these patients in the Central American and the Caribbean (CAC) region. This can lead to better clinical outcomes as well as quality of life for palliative patients. This document includes the formal expert consensus recommendations for scenarios of mutated and non-mutated mCRC, including synchronous or metachronous disease, management of mCRC with liver and lung metastasis, resectable, potentially resectable or non-resectable tumours and local in the CAC context.

The SBRT database initiative of the German Society for Radiation Oncology (DEGRO): patterns of care and outcome analysis of stereotactic body radiotherapy (SBRT) for liver oligometastases in 474 patients with 623 metastases

BACKGROUND

The intent of this pooled analysis as part of the German society for radiation oncology (DEGRO) stereotactic body radiotherapy (SBRT) initiative was to analyze the patterns of care of SBRT for liver oligometastases and to derive factors influencing treated metastases control and overall survival in a large patient cohort.

METHODS

From 17 German and Swiss centers, data on all patients treated for liver oligometastases with SBRT since its introduction in 1997 has been collected and entered into a centralized database. In addition to patient and tumor characteristics, data on immobilization, image guidance and motion management as well as dose prescription and fractionation has been gathered. Besides dose response and survival statistics, time trends of the aforementioned variables have been investigated.

RESULTS

In total, 474 patients with 623 liver oligometastases (median 1 lesion/patient; range 1–4) have been collected from 1997 until 2015. Predominant histologies were colorectal cancer (n = 213 pts.; 300 lesions) and breast cancer (n = 57; 81 lesions). All centers employed an SBRT specific setup. Initially, stereotactic coordinates and CT simulation were used for treatment set-up (55%), but eventually were replaced by CBCT guidance (28%) or more recently robotic tracking (17%). High variance in fraction (fx) number (median 1 fx; range 1–13) and dose per fraction (median: 18.5 Gy; range 3–37.5 Gy) was observed, although median BED remained consistently high after an initial learning curve. Median follow-up time was 15 months; median overall survival after SBRT was 24 months. One- and 2-year treated metastases control rate of treated lesions was 77% and 64%; if maximum isocenter biological equivalent dose (BED) was greater than 150 Gy EQD2Gy, it increased to 83% and 70%, respectively. Besides radiation dose colorectal and breast histology and motion management methods were associated with improved treated metastases control.

CONCLUSION

After an initial learning curve with regards to total cumulative doses, consistently high biologically effective doses have been employed translating into high local tumor control at 1 and 2 years. The true impact of histology and motion management method on treated metastases control deserve deeper analysis. Overall survival is mainly influenced by histology and metastatic tumor burden.

Resection of Liver Metastases in Colorectal Cancer in the Era of Expanding Systemic Therapy

About 25% of patients with colorectal cancer develop liver metastases after resection of the primary tumor, and surgical resection of the metastases offers the only opportunity for long-term survival. However, only 20% of patients present with resectable disease. Deciding which patients should be offered surgery, and which should receive additional treatment in the form of perioperative chemotherapy, is complex. For the majority of patients who present with technically irresectable liver-limited disease, systemic downsizing chemotherapy offers the only opportunity to reach surgery and potential cure. Molecular analysis of tumor tissue is improving patient stratification, allowing more appropriate treatment selection, but is not yet a regular part of clinical practice. Decision making is limited by a lack of clear prospective evidence, and so multidisciplinary team assessment is essential to optimize outcomes.

Selective internal radiation therapy for liver metastases from colorectal cancer

Liver metastases are often the dominant site of metastatic disease in colorectal cancer. Selective internal radiation therapy (SIRT) involves embolising radiolabeled spheres (SIR-Spheres) into the arterial supply of the liver. This review assesses the effectiveness and toxicity of SIRT in the treatment of metastatic colorectal cancer liver metastasis when given alone or with systemic or regional hepatic artery chemotherapy. We reviewed only randomised controlled trials comparing SIRT and chemotherapy (systemic and/or regional) with chemotherapy alone, or comparing SIRT alone with best supportive care. Only four randomized trials were identified. Due to heterogeneity of the patients and treatments received it was not possible to perform a formal meta-analysis, therefore this is a descriptive analysis only. All studies included patients with either liver only or liver dominant metastatic colorectal cancer. Two trials compared SIRT alone and SIRT with chemotherapy first line. The first with only 21 patients revealed a significant improvement in PFS and median survival with SIRT. The larger second study SIRFLOX of 530 patients comparing SIRT and current standard first line FOLFOX chemotherapy (+/- bevacizumab) with standard FOLFOX+/-bevacizumab alone. There was no improvement in overall PFS with addition of SIRT. In chemotherapy refractory patients SIRT and systemic chemotherapy (fluorouracil) improved progression free survival but not overall survival. A final study (63 patients) compared SIRT and regional chemotherapy (floxuridine) with regional chemotherapy alone in first line showed no significant difference in progression free survival and median survival. There remains a lack of evidence that SIRT improves survival or quality of life in patients with metastatic colorectal cancer. The overall survival results from SIRFLOX combined with FOXFIRE and FOXFIRE Global are awaited.