Selecting modalities

Importance of patient goals of care

Determining the appropriate treatment for a palliative patient is much more complex. All treatment decisions should be driven by the patient’s goals of care, which are much more variable in the palliative setting. Goals of care may be grouped into categories such as: remaining functional/active, remaining/becoming comfortable, spending time with family and friends, or living to a particular milestone. Although treatment intent is often dichotomized as either curative or palliative, patients will often have multiple goals that they wish to balance, and a desire to extend life is common even when cure is not possible. Some patients may have a high likelihood of extending their life through radiation therapy, whereas other patients will only have options related to improving or limiting distressing symptoms. The choice of treatment modality, as with dose-fractionation, should be based on the likelihood of meeting and balancing the patient’s most important goals of care.

Life expectancy and the balance of benefits and risks

Patient life expectancy is a critical consideration for choice of treatment modality, as it factors into the balance of treatment benefits with risks of adverse effects. Treatment benefits are primarily related to the total dose of radiation received by the target tissue, whereas adverse effects are often determined based on the dose-fractionation. Specifically, radiobiological considerations for dose-fractionation show that tissues causing late radiation effects are generally more sensitive to the dose per fraction than tissues causing early radiation effects. This difference between early and late effects of radiation treatment is exploited to ensure tumor control while limiting late adverse effects, as the tumor is usually highly sensitive to radiation therapy and represents an early responding tissue. For patients with a short life expectancy, however, late adverse effects are of no concern, as they will die before late effects are likely to develop. Thus, the balance between benefits and risks shifts for patients with a short life expectancy, as only early adverse effects need to be considered.

When determining the preferred treatment modality, a patient’s life expectancy should be estimated, and their individual probabilities of benefits and risks of early adverse effects should be considered carefully. At times, a patient’s life expectancy may be so short that there is no reasonable expectation of benefit regardless of radiation modality, in which case a patient should be recommended for supportive care alone. Most palliative patients referred to radiation therapy will have a life expectancy of weeks or months, long enough to expect a good response to radiation therapy. In these cases, radiation therapy can be recommended, but each treatment modality should be considered based on the likelihood of early adverse effects relative to the expected treatment benefits. Of course, life expectancy can only be imperfectly estimated, but the choice of treatment modality should be based on the reasonable expectation of prognosis.

Considering radiation treatment burden

Because the patient’s goals of care typically change in the palliative setting to emphasize goals other than extending life, the burden of treatment takes on additional prominence. The burden of radiation treatment primarily represents the energy and time spent in treatment, but any delay between consultation and completion of treatment also represents a burden. Patients intended for palliative radiation therapy are more likely to have advanced disease and progress significantly during even a single week for treatment planning. They may develop worsening symptoms during that time, or the treatment may be less effective for the greater tumor mass. Patients are often anxious to complete their treatment, and this is especially crucial among patients with a very short life expectancy. If a patient’s prognosis is only weeks, then spending a week waiting to start treatment represents a substantial fraction of their remaining lifetime. Patients may require extended hospitalization or a stay in a local hotel if they are frail or live a substantial distance from the radiation treatment site. Besides delaying their ability to spend time at home, this may represent a high cost to patients and families who may be concerned about upcoming expenses and possible loss of income. Because complex treatment modalities often require an extended planning time, patients may be better served by a simple modality provided quickly rather than a complex modality that may exacerbate each of these burdens.

Patients receiving palliative-intent radiation therapy may require a short duration of treatment time. For example, they may not be a candidate for curative treatments due to a serious comorbidity such as end-stage chronic obstructive pulmonary disease (COPD). These patients may have a limited ability to remain still or breathe according to a set pattern. Patients may also have difficulty maintaining the appropriate positioning. For example, they may be unable to tolerate lying flat for extended periods of time, due to pain, shortness of breath, or other symptoms. Even after tolerating a position during the initial simulation, a patient’s disease may have progressed significantly between simulation and treatment, limiting their ability to get into or tolerate the same position as required. For example, patients with superior vena cava (SVC) syndrome may now have greater collapse of their airways when lying supine.

Complex treatment modalities generally require a longer table time, as both the time for patient setup and the treatment delivery is usually longer than a simple modality would require. Extended setup times are generally related to the need for image guidance and include the time for imaging and position adjustments. For highly conformal, hypo fractionated regimens, the patient may need to wait for an evaluation of their positioning by a physicist and physician, given the increased risks involved. These requirements can add precious minutes to the time a patient is required to remain still and in a predetermined position.

Palliative patients will also usually have a poor performance status, which limits their ability to tolerate long days of treatment. Even if the table time for a given treatment is short, a day of treatment requires the patient to get out of bed, dress, travel to the treating facility, wait in the waiting room, change clothes, travel to the treatment room, be placed in the appropriate position, undergo treatment, change clothes again, travel home, and return to bed. For a patient with limited energy and motivation, this process exhausts their internal resources. Thus, their day will be structured around radiation treatment, instead of spending their day in other, personally meaningful activities. For patients with particularly poor performance status, they may remain exhausted for multiple days after treatment, based solely on their energy expenditure. Treatment courses with multiple doses may delay their ability to perform meaningful activities for weeks.

Although the burdens of treatment planning time, treatment time, and tolerating the treatment course are all present for patients receiving curative-intent treatment as well, the balance of benefits and burdens is notably different for patients receiving palliative-intent treatment. The benefits of palliative-intent radiation are clearly much smaller than that of curative-intent treatment, both in type and duration. Patients who are cured of their disease may have no additional symptoms related to that disease, and these benefits may last for many years. Patients receiving palliative-intent radiation may have substantial benefit for a particular symptom, but they may develop disease in another location that causes recurrent symptoms or they may have additional symptoms unaffected by the radiation. On the other hand, the burden of treatment is more likely to represent a greater hardship to the patient receiving palliative-intent radiation. These patients tend to be more frail and more symptomatic, so any discomforts are likely to be experienced more strongly. An individual patient’s goals may align more with spending time at home and remaining comfortable, indicating that shorter times for planning and treatment are desirable. The burden of even short times for planning and treatment will be more significant in a patient with a short life expectancy, as will the time between treatment and radiation effects which may be weeks or months. These times also are not expected to be offset by an increase in the patient’s life expectancy, as is likely in curative-intent treatment. The balance of benefit to the burden of palliative treatment should be carefully considered for each patient to ensure that the treatment modality chosen maximizes this balance and meets the patient’s goals.

Considerations particular to hospice patients

Hospice care is intended for patients with a prognosis of 6 months or less who have a goal of comfort rather than continued aggressive care. In the cancer setting, patients may also qualify for hospice if they are no longer a candidate for curative anti-cancer treatment, either due to their poor performance status or because they have progressed through the standard treatments and do not qualify for any reasonable treatment alternatives. Even among these patients, eligible patients are limited to those who refuse additional aggressive treatments, such as hospitalization or rehabilitation treatments.

Hospices are often hesitant to admit patients planning to pursue radiation therapy due to a concern that the patient’s goals are not focused on comfort. This perception is heightened if a patient is receiving a complex treatment modality, as most hospice providers have a limited understanding of the indications for using these modalities; they will generally assume that the intent is curative. It is essential to be clear in the documentation that the choice of modality is not based on a greater efficacy for the cure.

Hospices will often defer admission until after palliative radiation has been completed due to their concern for cost. Under the Medicare benefit, hospices are generally required to pay for and provide all care for the primary hospice diagnosis, related diagnoses, and symptom management. The primary hospice diagnosis is determined by the hospice medical director the time of admission and certification. Although somewhat subjective, it is intended to represent the main etiology for a patient’s limited life expectancy. For cancer patients, their cancer diagnosis is nearly always the primary hospice diagnosis. Thus, all cancer care for these patients is required to be provided by the hospice, while the hospice is paid a set per diemrate for each patient. This rate varies slightly based on the setting of patient care, but it is only a few hundred dollars per day.

If patients enrolled in hospice are planned to receive radiation therapy for their primary diagnosis, their hospices will be required to pay for these treatments out of their per diem reimbursement, which may be prohibitively expensive. If the indication for palliative radiation is the primary hospice diagnosis, or is related to this diagnosis, then the hospice may be able to pay for relatively inexpensive radiation treatment, but they will refuse to use a complex treatment modality while the patient is enrolled. The available options for treatment will then be: (1) to delay hospice enrollment until the palliative radiation is completed; (2) to simplify and shorten the treatment course to ensure that the hospice can afford to pay for concurrent palliative radiation; or (3) to enroll the patient in hospice and forego palliative radiation altogether. Deferring hospice admission ensures that the hospice is not required to pay for the radiation treatment, but it also delays the patient’s receipt of the benefits provided in hospice care. If the hospice can afford to pay for radiation treatment with a simple treatment modality, it may provide the best balance between the benefits of radiation while allowing early hospice enrollment.

Regulations for other insurance coverage may vary. In particular, pediatric patients and patients whose hospice is funded through the Veterans Health Administration are exceptions, as concurrent care is permitted in these cases. ^, Thus, the insurance for these patients will be independent of hospice care and radiation therapy. For these exceptions, it is crucial to ensure that the proper documentation is in place for concurrent care prior to planning with a complex treatment modality, as hospices may otherwise balk at the cost of this care. Even in these cases, a patient’s concurrent treatment should be intended for palliation and should not extend the estimated life expectancy beyond 6 months.

Availability of external beam radiation therapy

As the standard radiation therapy technology that developed in its current form by the 1970s, EBRT is widely available throughout the developed world. Machines used with EBRT can use Cobalt-60 or standard photon machines so this modality is available in the developing world as well, although less accessible overall. These machines are also less technically complex and do not require the same level of specialized knowledge for maintenance that a machine capable of a complex treatment modality may require.

The expertise required for creating EBRT plans and checking the calculations for radiation delivery are relatively straightforward, so the training required is also more readily available. Many of these plans are so highly standardized that the determination of radiation dosing can be determined with just a few measurements and tables.

Benefits to planning time

The primary benefit of using EBRT is the ability to limit planning time. Indeed, the use of EBRT may permit a patient to begin the radiation treatment course with virtually no planning. For example, a whole-brain radiation treatment plan may be standardized as lateral radiation beams with only the need to measure the diameter of the head, compute dosimetry, and apply a standardized cutout for each beam. Thus, a patient may be able to come for consultation and begin treatment within an hour.

Palliative radiation treatments are often given as a hypo fractionated dose, so that an extended time for planning may represent a time equal or longer than the radiation treatments themselves. If a patient needs to remain away from home and away from their family to complete their radiation course, especially if they need to remain hospitalized, it is particularly crucial to limit the time for planning. If the treatment itself can be completed within a few days, it is very frustrating for patients to have to remain hospitalized while they are waiting for days to a week just to start their treatment. Patients receiving palliative radiation therapy also may have a short prognosis, so this delay in meeting their other goals can be particularly upsetting. If the patients’ energy is substantially worse at the end of the week for planning, they may choose to return home even without receiving the entire course of treatment. Patients may also have worsened symptoms after the week of planning, which may result in a worse experience at home than they may have had with returning home without radiation treatment at all. Patients may prefer a less effective, shorter treatment if it will allow them to return home faster, and they often do not see the benefits of an extended time for planning radiation therapy.

Patients referred for radiation therapy often expect that they are going to begin treatment on the day of consultation, but this sense of anticipation may be much greater for patients referred for palliative-intent radiation therapy. They may have been told that they do not qualify for surgery, chemotherapy, and immunotherapy treatments, so that they are anticipating radiation therapy as their sole cancer treatment.

Benefits to treatment time

EBRT is also efficient in the amount of time spent receiving treatment. It is delivered in a straightforward manner, with limited need to image to ensure perfect alignment prior to delivery. The portals for EBRT are generally determined based on bony markers that are easily visible on digitally reconstructed radiographs (DRR). Between the use of skin markers and adjustments based on DRRs, a patient can be appropriately aligned within a minute or two. It is also easy for radiation therapists to ensure the correct positioning without the need for double checks from physicists or physicians. This method allows patients to limit the duration of time that they need to be in a specific position before delivering radiation.

The time of radiation treatment is also rapid, regardless of the type of machine used. Although more complex, expensive machines have been developed to rapidly deliver radiation using intensity modulated radiation therapy or stereotactic body radiation therapy, these machines are relatively new and not as widely available. EBRT plans can be delivered rapidly using basic photon or Cobalt-60 machines, without the need for specialized equipment. In settings with a large ratio of patients to machine time, this option is particularly beneficial.

Concerns regarding adverse effects

As with much of medicine, the first guiding principle of palliative radiation therapy should be “Do no harm...” For the palliative patient, life expectancy is usually short, so this principle generally translates into avoiding acute adverse effects of radiation therapy. Complex treatment planning is much more effective at avoiding sensitive, normal tissues, thus limiting acute adverse effects. With planning, a few fundamental decisions can be made to avoid particularly radiosensitive tissues (e.g., off-angle treatment of vertebrae to avoid overdosing the spinal cord), but the complexity is limited.

Without the benefit of image guidance, setup accuracy is also reduced. If treatment is hypo-fractionated, as is common in palliative radiation therapy, there is much averaging effect throughout the treatments. If the patient setup is inaccurate, the patient may receive much of the radiation dose to normal tissues outside of the target, which may be avoided when image guidance is used. The patient may also receive a reduced dose to the target tissue unless generous margins are used. Treatment margins then require a trade-off between ensuring the target tissue is exposed sufficiently to ensure treatment benefit and reducing the normal tissue exposure to avoid adverse effects.

Concerns regarding re-treatment

Patients receiving palliative radiation therapy may be treated with a low total radiation dose, which ensures that they have the option for re-treatment to the same anatomic region in the future. It may be helpful to keep this possibility in mind when considering the initial treatment modality. The option to treat with a lower total dose is more influential than when considering the treatment modality for the additional courses. The risk of adverse effects increases with each course of radiation therapy as the radiation dose to each tissue gets closer to its total tolerance.

Patients under consideration for palliative radiation therapy may also include those who have progressed despite prior, curative-intent treatment. For these patients, the choice of treatment modality may be limited to limit the risk of catastrophic adverse effects. If a particular tissue tolerance has already been reached, it may be important to use a more complex modality to limit additional exposure to that tissue.