Oligometastatic Disease Management: Finding the Sweet Spot

Abstract

Hematogenous dissemination represents a common manifestation of squamous cell carcinoma of the head and neck, and the recommended therapeutic options usually consist of systemically administered drugs with palliative intent. However, mounting evidence suggests that patients with few and slowly progressive distant lesions of small size may benefit from various local ablation techniques, which have already been established as standard-of-care modalities for example in colorectal and renal cell carcinomas and in sarcomas. In principle, serving as radical approaches to eradicate cancer, these interventions can be curative. Their impact on local control and overall survival has been shown in numerous retrospective and prospective studies. The term oligometastatic refers to the number of distant lesions which should generally not surpass five in total, ideally in one organ. Currently, surgical resection remains the method of choice supported by the majority of published data. More recently, stereotactic (ablative) body radiotherapy (SABR/SBRT) has emerged as a viable alternative. In cases technically amenable to such local interventions, several other clinical variables need to be taken into account also, including patient-related factors (general health status, patient preferences, socioeconomic background) and disease-related factors (primary tumor site, growth kinetics, synchronous or metachronous metastases). In head and neck cancer, patients presenting with late development of slowly progressive oligometastatic lesions in the lungs secondary to human papillomavirus (HPV)-positive oropharyngeal cancer are the ideal candidates for metastasectomy or other local therapies. However, literature data are still limited to say whether there are other subgroups benefiting from this approach. One of the plausible explanations is that radiological follow-up after primary curative therapy is usually not recommended because its impact on survival has not been unequivocal, which is also due to the rarity of oligometastatic manifestations in this disease. At the same time, aggressive treatment of synchronous metastases early in the disease course should be weighed against the risk of futile interventions in a disease with already multimetastatic microscopic dissemination. Therefore, attentive treatment sequencing, meticulous appraisal of cancer extension, refinement of post-treatment surveillance, and understanding of tumor biology and kinetics are crucial in the management of oligometastases.

Current Therapeutic Strategies in Patients with Oropharyngeal Squamous Cell Carcinoma: Impact of the Tumor HPV Status

“…Local therapy (surgery, stereotactic RT) is a valid therapeutic option for patients with a single metastatic or oligometastatic disease [94]. In other cases, systemic therapies will be delivered according to previous treatments received, general health status (PS) and comorbidities, tumor spread and patient symptoms, and PD-L1 tumor expression.…”

Genetic analysis of single disseminated tumor cells in the lymph nodes and bone marrow of patients with head and neck squamous cell carcinoma

“…However, ~20-30% of these patients develop locoregional relapse and even distant metastases at low frequency [5]. These rates are higher in locoregionally advanced stages, without distant metastases [6]. Such relapses seem to emerge from micro-deposits and individual cancer cells that have disseminated before tumor resection and are termed minimal residual disease (MRD).…”

Single-Center Experience of Focal Thermo-Ablative Therapy After Pelvic Radiotherapy for In-Field Prostate Cancer Oligo-Recurrence

“…The concept of oligo-metastatic disease, originating in Hellman and Weichselbaum theories over 20 years ago, showcases growing interest, notably with the development of more accurate imaging modalities, precise focal treatments like stereotactic body radiation therapy (SBRT), and more conservative surgery procedures ( 4 , 5 ). In PCa, led by advances in terms of imaging with the successive appearance of more sensitive radiotracers in 18F-sodium fluoride (NaF), 18F-Choline, and 68Ga-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT), as well as emerging therapies offering prolonged survival, oligo-metastatic disease is increasingly diagnosed.…”