Palliative radiation

Chart and imaging review

Determining whether palliative radiotherapy may benefit a patient requires assimilating data from chart and image review, consultation with the patient, and at times, discussion with the patient’s medical oncologist ( Table 6.1 ). Chart review provides information on the patient’s tumor histology, which can help predict response to radiotherapy and/or systemic therapy and guide treatment recommendations. Distinction should be made between a tumor’s radio-responsiveness, which reflects how rapidly the tumor will decrease in size, and a tumor’s radio-sensitivity, which reflects the likelihood of durable local control with radiotherapy. For example, in the scenario of malignant epidural spinal cord compression (MESCC), radio-responsiveness influences whether surgical decompression is required, whereas radio-sensitivity influences the radiation technique and dose/fractionation. Radio-responsive tumors such as multiple myeloma, Hodgkin and non-Hodgkin lymphoma, and chloromas may preferentially be treated with radiotherapy instead of surgery in the setting of MESCC, and in select clinical scenarios (i.e., multiple sites of active disease in addition to site of MESCC), systemic therapy may be recommended over either surgery or radiation. In contrast, radioresistant histologies such as sarcoma, melanoma, renal cell carcinoma, thyroid carcinoma, colorectal cancer, and non–small cell lung cancer (NSCLC) may benefit from surgical decompression for MESCC to relieve neurologic symptoms and improve functional outcomes. Beyond tumor histology, a tumor’s molecular profile influences both prognosis and predicts response to systemic treatment, though data on whether this influences response to and durability with radiation are relatively sparse, if not absent. Nonetheless, it may increasingly be incorporated as part of clinical decision making.

A patient’s prior treatment history provides context for where the patient is in their disease course and likelihood of available, effective systemic therapies, if any. Other pertinent treatment history includes prior radiotherapy, which informs the patient’s ability to tolerate treatment and in cases where the same or adjacent site will require radiation, whether it is safe and feasible to deliver a meaningful radiation dose. The patient’s current systemic therapy should be noted and whether there could be increased toxicity with concurrent administration during radiotherapy. For example, given the potential for synergistic neurotoxic effects between methotrexate or cytarabine and CNS-directed radiation, a minimal interval of 48 to 72 hours between the last dose of chemotherapy and initiation of CNS-directed radiation should be given, and if possible, delaying initiation of CNS-directed radiation 2 to 4 weeks is ideal.

Diagnostic imaging provides crucial information, including the patient’s current disease burden and extent of disease, radiographic correlates to the patient’s clinical signs and symptoms, and adjacent organs at risk (OAR) that may influence radiation’s toxicity profile. Understanding a patient’s extent of disease may inform the utility and length of local therapy. A patient with extensive and progressive disease may not tolerate a significant period off systemic treatment for radiotherapy; a short course of radiotherapy, or temporarily deferring radiotherapy for systemic therapy, may be preferred. Or, if no systemic therapies are available, the radiotherapy course should be kept short to maximize the patient’s QoL. In addition to identifying radiographic correlates for a patient’s symptoms, imaging can provide information about whether the radiographic abnormality is treatable with radiation. Non-tumor lesions, such as retropulsed bone into the epidural space in the setting of a vertebral body compression fracture, may require alternative management to alleviate the patient’s symptoms (e.g., surgery). Review of imaging may also prompt consideration of additional imaging, including more recent imaging and/or other imaging modalities to further characterize a lesion. For example, a patient with back pain and lower extremity weakness with a CT-abnormality of the spine may benefit from an MRI of the spine to evaluate for potential tumor epidural involvement.

Other data review includes laboratory values to identify potential cytopenias, renal insufficiency, and abnormal liver function, which may be exacerbated in the setting of pelvic/spine, peri-renal, and upper abdominal radiotherapy, respectively. These may also inform whether routine labs will be followed during the radiation course.

Consultation with patient

Meeting and examining the patient is an opportunity to confirm the patient’s notable symptom(s), assess their functional status, discuss treatment preferences and goals of treatment, and review potential side effects of radiotherapy. For patients with pain, it is important to understand the onset and duration, whether the pain is diffuse versus localized, its severity, which factors improve or worsen the pain (e.g., pain with weight bearing), and temporal relationship with systemic therapy. In the latter scenario, increasing symptoms from cancer may often prompt changes in systemic therapy. Though the response rates are not uniformly high, patient symptom(s) may respond to the new systemic therapy at the time of their radiation oncology consultation, lowering the therapeutic ratio of palliative radiotherapy.

Chart review and meeting the patient provides an impression of the patient’s functional status, which should then be quantified with scales such as the Karnofsky performance status (KPS) or Eastern Cooperative Oncology Group (ECOG) ( Table 6.2 ). At the minimum, performance status informs whether a patient can get on and off the table, lie down for treatment, and/or tolerate trips to receive treatment. In addition, performance status, estimated using either KPS or ECOG, is one of the strongest predictors for life expectancy in advanced cancer patients. This is reflected by its inclusion in prognostic models, regardless of whether the model is based on training cohorts of patients seen for palliative radiotherapy ^, or patients with a specific cancer type (e.g., lung cancer) receiving palliative radiotherapy. In addition to its utility with estimating prognosis, performance status may predict a patient’s tolerance to the acute side effects of radiotherapy. Among patients with advanced NSCLC and poor performance status (KPS 30-4), receipt of palliative thoracic radiation (20 Gy/5 fractions) improved symptoms of hemoptysis compared to patients who elected just to have supportive care, though palliation of pain was higher among the supportive care group. However, acute toxicity was notable among patients treated with palliative thoracic radiation. This included 23 patients (18%) that developed pneumonitis (grade 3 in 12, grade 4 and 5 in 11) and grade 4 radiation-induced esophagitis (4%) requiring enteral and parental support.