Introduction

In a 2010 Canadian study, ~3700 new cases of spinal cord injury (SCI) were discharged into the community annually, with prevalence estimated at 85,556 persons (51% traumatic; 49% non-traumatic) [1]. Although SCI incidence historically has been higher in men, research has shown a bimodal pattern in women, with incidence increasing over age 60 from both traumatic and non-traumatic causes [2].

Breast cancer is the most common cancer in women worldwide, with ~1:8 women diagnosed in their lifetime, a risk that increases with age [3]. With more women, especially older women, living with SCI – the concordance of women with SCI and breast cancer is increasing. To our knowledge, no peer-reviewed publications have addressed the issue of adverse health conditions resulting from breast cancer treatment in women with SCI. Furthermore, no research databases on this topic exist. This is a huge concern as we know that women with SCI are less likely to be fully adherent to recommended breast (and cervical cancer) screenings and more likely not to be screened during eligible years as compared to women without SCI [4].

Despite advances in breast cancer treatment contributing to increasing overall survival [3], significant treatment-related adverse health outcomes continue to occur [5]. These conditions negatively influence the quality of life (QOL) for able-bodied women treated for the disease but even more so for women living with pre-existing SCI. Details of the challenges due to these health conditions will be discussed in greater detail in this paper

The goal of this Perspective Paper is to increase awareness among general practitioners, rehabilitation physicians, gynecologists, and other healthcare providers about key interventions and rehabilitation needs of women with SCI treated for breast cancer. Specific objectives were to: (1) to give an overview of breast cancer treatment-related health conditions that need special attention in women with SCI and (2) to inspire researchers to study the consequences of breast cancer-related health conditions in women with SCI. The philosophical stances (or “positionality”) of this paper’s authors were influenced by the fact that three have had breast cancer with two also having SCI or spinal cord disease.

Breast cancer treatment-related adverse health conditions facing persons with SCI

Shoulder limitations

Independence in mobility is a significant factor affecting QOL in people with SCI because most rely on some form of wheeled mobility [6]. For manual wheelchair users, shoulder function is critical in maintaining independence. Even for women who use powered wheelchairs, weight bearing remains important for transferring into and out of the chair; shoulder range of motion (ROM) is critical for reaching from a seated position. Therefore, maintaining shoulder mobility and functional independence is essential for social integration and QOL.

Unfortunately, breast cancer treatments pose significant risks to shoulder mobility. Shoulder movement restriction, upper limb weakness and pain are commonly reported surgical outcomes [4]. Long-term follow up has shown that women who have undergone breast cancer treatment have lower self-reported shoulder function than women without breast cancer [7]. Thus, it is critically important to consider the implications of breast cancer treatment-related adverse health outcomes in individuals with SCI that may compound pre-existing disability.

Full shoulder ROM is essential for wheelchair propulsion; decreased range could lead to less efficient propulsion or inability to wheel at all. Severity of ROM impairment can vary with surgical technique, with women undergoing breast-conserving surgery typically exhibiting better outcomes than those having total or modified radical mastectomy. A systematic review found that able-bodied individuals who underwent mastectomy were far more likely to experience shoulder restriction than individuals who underwent breast-conserving surgery [6]. Unfortunately, research indicates that persons with disabilities were less often diagnosed early through routine mammography, had breast-conserving surgery less often than total mastectomies, and less likely to have reconstruction following a mastectomy [8]. This is unfortunate, considering that for most women with early-stage breast cancer, breast-conserving surgery combined with adjuvant radiotherapy is equivalent in survival and recurrence rates to total mastectomy [9].

Radiation-induced fibrosis is another complication with potential to obstruct shoulder ROM. Muscular fibrosis can impair mobility, strength and function at the shoulder [10] and increases risks for shoulder impingement [11], intensified by repetitive use of shoulder motion in wheelchair users [5]. This potential complication should be considered in deciding to proceed with radiation to the breast, chest wall and regional nodes in individuals with SCI who use wheelchairs for primary mobility. Monitoring of the effects of surgery and radiation should occur to ensure maximal shoulder mobility retention.

Lymphedema

Upper extremity lymphedema is a well-documented phenomenon related to the extent of local and regional surgery and radiation. Those who have had complete axillary lymph node dissection (ALND) with axillary radiation are at highest risk of developing this condition. The number of resected axillary nodes remains the greatest risk for treatment-related morbidity [12], which can also include sensory disturbances, pain, and functional impairment [13].

In women with SCI, lymphedema increases the burden of disability, impacting the ability to complete daily routines. Lymphedema also increases the potential for compromised skin integrity and infection, a pervasive concern in that denervation after SCI leads to many physiological changes, including decreased skin integrity [14]. ALND treated individuals should be monitored for side effects, with special consideration and surveillance for individuals with SCI to detect and address impairments and lymphedema in the upper limb. In particular, healthcare providers should remain vigilant about skin inspection in insensate underarm areas [14]. A wound care nurse may provide patient education around skin care, especially if significant lymphedema occurs, particularly important for individuals with higher-level spinal cord lesions and greater areas of decreased sensation.

Pain

Chronic cancer pain is multifaceted and can originate from the cancer itself and its treatment. Unfortunately, persistent pain after breast cancer treatment is relatively common, with 42–56% of able-bodied individuals reporting arm and breast pain 24 months after surgery [7]. Due to increased demands on the shoulder joint, shoulder pain is already present in more than 30% of persons with SCI [15]. Breast cancer individuals with paraplegia and shoulder pain have limited ability to exercise aerobically, unlike able-bodied survivors who can walk briskly or jog. Because physical activity has been shown to alleviate treatment-related side effects [16] as well as minimize cancer recurrence and mortality [17], persistent shoulder pain in those with SCI precludes a healthier lifestyle that could have significant overall benefits.

Moreover, greater pain intensity is associated with lower levels of self-perceived health [15], of particular concern as chronic pain was present in 38.3% of 261 able-bodied individuals after breast cancer treatment especially in the axilla, excised breast area, medial arm, ipsilateral chest and mastectomy scar [18]. In addition, a significant proportion of individuals treated with aromatase inhibitors as adjuvant hormone therapy experience treatment-induced arthralgia and myalgia [19], making ongoing pain management essential for individuals with SCI.

Fatigue and mental health

Fatigue is a common disabling symptom in cancer individuals and survivors. Cancer-related fatigue differs from other manifestations of fatigue because it is generally not alleviated by sleep or rest, is typically of greater duration and severity, is often associated with high levels of distress, and is disproportionate to exertion [20]. Cancer-related fatigue often occurs with other troublesome symptoms such as pain, sleep disturbance, and depression [20]. The impact of fatigue on QOL can be substantial, reducing the patient’s engagement in work, personal and social activities and suggesting the need for psychological support.

Fatigue is especially problematic for those who already rely on upper extremity strength for mobility. Loss of strength and endurance can be especially challenging for manual wheelchair users possibly resulting in mobility loss or forcing them to transition to powered mobility options, such as power assist for their current chair, or a powered wheelchair. While fatigue is often discussed in terms of physical weakness and lack of endurance, there is also significant interplay among fatigue, depression, and pain [21]. We know that a significant negative association exists between fatigue and community participation for individuals with SCI, even when controlling for pain, depressive mood and comorbidities [22]. Adding another traumatic event such as breast cancer with its own known fatigue and mental health complications [23] further exacerbates the mental health challenges these women face and thus needs attention during and after treatment is finished.

Bladder, bowel, skin care, and autonomic dysreflexia

Persons with SCI are at risk for both neurogenic bladder and neurogenic bowel dysfunction; both conditions can increase risks for autonomic dysreflexia and pressure sores [24]. Because autonomic dysreflexia is potentially life threatening, oncology clinicians treating individuals with SCI should be aware of this possible complication, sit the patient upright, and enable her to remove the triggers of a full bladder and/or bowel [25]. Risk of incontinence for those who use intermittent catheterization during long chemotherapy sessions is high, thus using an incontinence pad or providing close proximity to restrooms is advised. Oncologists and individuals should be aware that chemotherapy-induced peripheral neuropathy could exacerbate pre-existing neurogenic bladder or bowel problems [26].

Development of pressure sores is a continuing concern among the SCI population, with long chemotherapy regimens shown to increase wound risks. Women with SCI undergoing chemotherapy are particularly at risk of developing pressure sores due to myelosuppression, steroid use, malnutrition, increased infection risk, and potential complications of autonomic dysreflexia and reflex sweating, as noted in a case study [27].

Issues with skin care are also a concern with radiation therapy. Accurate positioning on the radiation table and maintaining that position are crucial for effective and safe delivery of radiation. This challenge is achieved in some facilities through manual assistance offered by technicians or family members who accompany the patient. Rarely, however, are ceiling lifts, height-adjustable radiation tables or adaptive hand bars available to allow assisted or independent positioning, thereby posing risks for skin breakdown during transfers [25]. Also, radiation dermatitis occurs in 85–95% of individuals [28]; thus, skin care protocols must be adhered to for those with decreased sensation, a particular concern for individuals with tetraplegia.

Immune suppression

It is well documented that SCI-induced immunodeficiency can lead to increased susceptibility to infection that results in higher morbidity and mortality. Thus, women who require adjuvant chemotherapy may exacerbate this compromised immunity. A recent study showed that while CD8+ T cell immunity successfully can regenerate, the CD4 compartment could be irreversibly damaged [29].

Osteoporosis

Chemotherapy-related ovarian failure, gonadotropin hormone-releasing agonists, and aromatase inhibitors can all contribute to bone loss that, in some women, is of sufficient magnitude to lead to osteoporosis and subsequent fractures. This risk increases in postmenopausal women with breast cancer and potentially those with SCI who are already at risk for osteoporosis due to lack of weightbearing activities [30]. Based on a recent systematic review, prophylactic bisphosphonates to prevent fractures in the general SCI population is minimal [31], however, there is support for bisphosphonate use for those with very low bone mineral density (T-score <-2.0) [32]. Bone mineral density should be closely monitored in women with SCI and breast cancer, especially post-menopausal women and those receiving chemotherapy and/or aromatase inhibitors.

Conclusions

Although no specific data exist on how many women with SCI will experience breast cancer, the rising prevalence of both conditions increases the likelihood of concurrence. Consequently, women with SCI need to follow preventive mammogram screening similar to the able-bodied population. We cannot provide evidence-based guidelines within the limited current literature, but we can encourage rehabilitation physicians to be consulted in the early stages of breast cancer and to be part of the interdisciplinary team treating women with breast cancer. Recognizing these women have been through two incredibly traumatic events means they also need extra care and sensitivity towards their mental wellbeing, as well. We hope this paper inspires large database groups to begin to capture data about other health care conditions for women with SCI across the lifespan, like breast cancer, that will provide more evidence for future publications.