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Top 3 Musculoskeletal Side Effects of Breast Cancer Treatment

Complaints of upper body pain and dysfunction are common in patients who have had breast cancer treatment. Pain that occurs in the early period following surgery, radiation or chemotherapy is to be expected; but many women are surprised to learn that longer-term disorders can also arise as a side effect of breast cancer treatment, and these disorders are more common than you might think.

As many as 7 in 8 women treated for breast cancer experience one or more upper body pain or dysfunction disorders because of their treatment (ref 1).

In fact, it’s not surprising that so many women experience long-term complications from breast cancer treatment. As impressive as current oncological treatment tools are, surgery, radiation and chemotherapy create significant collateral damage to surrounding cells and tissues. The more extensive the tumour or stage of disease, the more extensive the treatment, and the greater the risk of collateral damage. This collateral damage is responsible for the varied and numerous side effects of breast cancer treatment.

The long-term side effects of breast cancer treatment can be grouped into three broad categories: (1) musculoskeletal disorders, (2) nerve disorders, and (3) edema (swelling) disorders. I’ll be covering the most common musculoskeletal disorders below.

For more side effects of breast cancer treatment, please see: Top 4 Nerve Disorder Side Effects of Breast Cancer Treatment

Musculoskeletal disorders include any pain or dysfunction related to muscles, joints or the skeletal system. Broadly speaking, breast cancer treatment can cause musculoskeletal disorders by damaging normal cells and tissues which in turn can disrupt the complex interplay between muscles, tendons, nerves, fascia (connective tissue), and joints. The result can be acute or chronic pain, weakness, reduced range of motion, and altered movement patterns.

Here I discuss the top 3 musculoskeletal side effects of breast cancer treatment including their cause, symptoms, and treatment.

Rotator Cuff Tendonitis

The rotator cuff is a collection of four muscles and their associated tendons that act to keep the shoulder joint stabile and functioning normally. In other words, they act together to keep the head of the ‘humerus’ (upper arm bone) positioned inside the joint grove of the ‘scapula’ (the shoulder blade) as the arm moves. When these muscles and tendons fail to work together properly due to injury, weakness, or altered motor patterning, the result can be pain, inflammation, increased risk of tendon degeneration/tearing, decreased range of motion, and reduced shoulder function.

Rotator cuff tendonitis is very common in the general population, a result of the high demands we place on this impressively mobile and complex joint. It is also one of the most common musculoskeletal side effects of breast cancer treatment.

Description and Causes

Rotator cuff tendonitis is an inflammation of one or more rotator cuff tendons in the shoulder. This inflammation causes pain with movement, muscle weakness, and can contribute to the risk of tearing a tendon. Tendon tears further intensify pain and diminish shoulder function.

The predominance of rotator cuff tendonitis in breast cancer patients likely arises due to multiple factors, but rubbing or impingement of the rotator cuff tendons between the shoulder joint’s bony surfaces (the head of the humerus and the shoulder blade’s ‘acromion’) is usually part of the underlying cause.

Why would breast cancer treatment cause shoulder tendonitis?

  1. Scarring. Breast cancer treatment typically involves surgery (either lumpectomy or mastectomy), which creates scar tissue in the breast or on the chest itself. An additional incision closer to the armpit is commonly necessary to retrieve lymph nodes, which introduces further scarring.  Both surgical scar sites, and the necessary restrictions placed on overhead range of motion in the early post-operative phase, can contribute to altered mechanics at the shoulder joint.  This, in turn, can cause the rotator cuff tendons to become impinged while performing certain arm movements.  It can also mean that the muscles of the rotator cuff have to work harder to overcome this chest/armpit tightness, which further contributes to strain and inflammation.
  2. Radiation. Radiation also causes tissue changes within the chest/breast, armpit, neck, and back areas, depending on the treatment field. These tissue changes can include not only a burning to the skin, but also a tightening of muscles and tissues underneath. These changes create further restrictive forces on the shoulder joint’s normal movement pattern and range, causing further irritation and inflammation of the rotator cuff tendons.
  3. Posture. Another often overlooked contributing factor is altered upper body posture following cancer treatment. Postural changes are extremely common in patients after treatment and these often promote faulty biomechanics at the shoulder joint, leading to tendonitis.
  4. Weakness. Altered use or disuse of the arm (at first, due to post-operative restrictions, but later, due to pain, tightness, fear, or out of habit) can lead to further weakness of the rotator cuff muscles, putting patients at even higher risk of tendonitis. Weakness of the muscles of the rotator cuff, shoulder blade, or other stabilizing muscles will decrease the dynamic stability of the shoulder joint. This can decrease how well the humerus is held in an optimal position in the joint during movement. Even a subtle shift in the position of the humerus bone can cause impingement of the rotator cuff, which, if this becomes a persisting pattern, can lead to tendonitis.

Symptoms

The primary symptom of rotator cuff tendinitis is pain in the shoulder with movement. Actions such as reaching behind the back, reaching overhead, or picking up something with an outstretched arm, are common aggravating movements.

Diagnosis

The diagnosis of rotator cuff tendonitis is typically made through a physical assessment of shoulder movement pattern, strength testing of the specific muscles involved, impingement tests, an assessment of postural contributing factors, and an examination of any tenderness on palpation of the tendons or other actions that are associated with pain. Ultrasound imaging or Magnetic Resonance Imaging (MRI) are usually not necessary, but could offer definitive diagnosis. The presence of additional shoulder issues such as adhesive capsulitis (‘frozen shoulder’) can make the diagnosis of tendonitis more difficult.

Treatment and Prevention

The standard treatment for rotator cuff tendonitis is physiotherapy and over-the-counter non-steroidal anti-inflammatory drugs. Physiotherapy techniques including exercise therapy can be used to strengthen weak muscles at the shoulder, mid and upper back, and decrease inflammation.  Improved biomechanics and motor patterning is essential to alleviate the tendonitis, and releasing the tight and/or scarred tissue (be it from surgery or radiation or both) is also often necessary. In severe cases that do not respond well to conservative treatment, steroid injections may be beneficial to provide further anti-inflammatory pain relief.

How to prevent impingement of the rotator cuff tendons

  1. Regularly perform rotator cuff strengthening exercises. In the photos below I demonstrate a particularly safe and effective rotator cuff exercise that does not require special equipment or detailed instruction. There are a variety of additional exercises that can be used to improve the function of the rotator cuff, although many are difficult to perform correctly without additional equipment and close instruction provided by a physiotherapist or other knowledgeable professional.
  2. Avoid or modify physical activity that can predispose you to impingement. If you regularly lift weights, there are certain exercises that you should either modify or avoid entirely. You can learn more here: ‘Weight Training and Shoulder Pain: Subacromial Impingement Syndrome’.
  3. Seek out the help of a physiotherapist or massage therapist who is familiar with breast cancer treatment-related tissue changes, to address any persisting tightness across the chest/armpit from surgery and/or radiation. At the same time, a physiotherapist can also provide you with a shoulder strengthening routine that you can perform at home.
Lindsay performing rotator cuff exercise to help shoulder tendonitis, one of the side effects of breast cancer.

A simple yet effective rotator cuff exercise to help maintain rotator cuff strength following breast cancer treatment.  Hold a light weight in the hand, and lie on your side.  The starting position is with your elbow resting against you at a 90 degree bend, holding a light weight in your hand.  Keeping your wrist flat, rotate the arm so that the hand lifts toward the ceiling, keeping your elbow against your side.  A good starting point is 3 sets of 8 – 10 repetitions, performed 3 – 4 times/week.  DO NOT do this exercise if an appropriate weight cannot be found to perform it pain-free.

 

Adhesive Capsulitis (‘Frozen Shoulder’)

Adhesive Capsulitis, commonly called ‘frozen shoulder’, is another of the frequent side effects of breast cancer treatment. It is also relatively common in the general population where it can affect as many as 3%-5% of people, and 10%-20% of individuals with diabetes (ref 2).

Description and Causes

A frozen shoulder is both painful and restricts the shoulder’s range of motion. Although the underlying pathogenesis is unclear, it often occurs following a shoulder injury or other traumatic event. Shoulder inactivity, even if only temporary such as following an injury, is a strong contributing factor. Inactivity or disuse appears to promote inflammation of the connective tissue called the ‘synovial membrane’ which lines the shoulder joint. If persistent, this inflammation will ultimately result in fibrosis (scarring). This fibrosis thickens the connective tissue around the shoulder joint, and along with inflammation, tightens the joint capsule and restricts mobility.

Why would breast cancer treatment predispose women to frozen shoulder syndrome?

Because inactivity predisposes patients to developing frozen shoulder, and inactivity is common in breast cancer patients:

  1. Patients are recommended to limit use of the arm following surgery. After breast cancer surgery patients are typically given the instruction to limit both the use and range of motion of the arm on the same side, for a period of days/weeks to allow the surgical site to heal.
  2. Patient arm movement is often limited by pain or fear of pain. Pain from surgery (breast, lymph node or reconstruction), radiation, rotator cuff tendonitis, nerve damage, cording, or other side effects of breast cancer treatment including lymphedema can lead to shoulder underuse, either consciously or subconsciously.

Symptoms

The symptoms of a frozen shoulder change as the condition progresses and then resolves. They can be broken down in to three phases:

Symptom onset (‘freezing’)

The initial stage of frozen shoulder onset is dominated by inflammation, and so it can be very painful to move. Pain tends to limit shoulder use, and this in turn can encourage further progression of the condition.

Classic frozen shoulder (‘frozen’)

After what a period of weeks or months of persistent inflammation, the condition progresses to a classic ‘frozen’ shoulder presentation. Sufficient fibrosis and inflammation has now accumulated to significantly restrict both active range of motion (how much your arm can move on its own) and passive range of motion (how much I could move your arm when you are relaxed). Pain at rest tends to be less than during the initial stage of onset, however pain can still be significant when the arm reaches its limits of range of motion.

 Resolution (‘thawing’)

As a frozen shoulder begins to heal, pain typically reduces further and range of motion begins to improve.

Diagnosis

Diagnosis is usually made based on a description of symptoms in combination with a physical assessment of the pattern of loss of range of motion at the shoulder joint.

Treatment and Prevention

Frozen shoulders arising as a side effect of breast cancer are usually self-limited, which means that they will normally resolve on their own. Unfortunately, this process can take upwards of 1-3 years, and without therapy including specific strengthening exercises, function and/or range of motion of the shoulder may not be fully restored. As with other musculoskeletal side effects of breast cancer treatment, conservative treatment options are available, and have been shown to offer benefit.

Patients can benefit from conservative treatments that can help speed-up and maximize recovery.

Conservative “first-line” treatments for frozen shoulder are nearly always recommended. These include: physiotherapy, anti-inflammatory medication, and occasionally, injections (steroid or hyaluronate). Unfortunately, there are not yet enough high-quality clinical studies to help us understand the relative benefits of these treatments either alone or in combination. Physiotherapy stretching and strengthening exercises may help to prevent further loss of range of motion, and when the shoulder is ready, help increase the range of motion.

A smaller number of patients may require more aggressive “second-line” treatment including: blocking the suprascapular nerve with an injection of anesthesia and steriod which can reduce pain signals and when added to physiotherapy may help improve functional recovery (ref 3); arthrographic distension (injecting fluid to break up fibrosis) may provide short-term benefits (ref 4), and manually stretching the shoulder joint under general anaesthetic may also be effective (ref 4). A small number of patients who develop severe cases may be candidates for surgical release (arthroscopic capsular release).

Breast cancer patients with frozen shoulder resulting from surgery, and who have no other underlying shoulder conditions, typically respond well to conservative treatment and recover completely. Whereas patients with other side effects of breast cancer treatment that underlie the frozen shoulder, such as nerve impingement/irritation or rotator cuff tendinopathy, may require more aggressive avenues of treatment (ref 5).

How to prevent frozen shoulder

  1. Maintain good shoulder health by following the prescribed exercises following your breast cancer surgery. This can help maintain basic muscle strength and shoulder/shoulder blade range of motion. Incorporating exercise into your recovery can help reduce the risk of this and other side effects of breast cancer treatment.
  2. Be careful not to be overly protective of your shoulder during and following breast cancer treatment. Resuming normal activities (and exercise) as soon as possible is beneficial. However, pain should be your guide. Activities that cause pain at your shoulder should generally be avoided to prevent inflammation, further pain, and further activity avoidance.
  3. If you do experience pain in your shoulder, seek out professional advice early. Your physiotherapist can assess your shoulder joint, rotator cuff, and muscle patterning/function, and provide you with a specific list of do’s and don’ts, exercises, and hands-on manual therapy as needed. This can help ease your recovery from the breast cancer treatment, and potentially prevent progression to more significant shoulder complications.

Trapezius Myalgia Syndrome

Trapezius myalgia syndrome, often experienced as neck-shoulder tension, is another of the commonly observed side effects of breast cancer treatment.

Description and Causes

Trapezius myalgia (myalgia meaning muscle pain) refers to dysfunction and pain arising in the large trapezius muscle that joins the back of the head/neck, to the shoulder blade and spine.  Its function is to stabilize the shoulder blade and rotate it upward as the arm elevates.  There are several risk factors shown to contribute to the development of trapezius myalgia, including but not limited to: holding prolonged positions at work, repetitive tasks, weakness in the upper body, and a past history of neck dysfunction.  This syndrome is most commonly found in women in the general population.

Why would breast cancer treatment predispose woman to pain in the neck-shoulder region?

Tightness across the chest (from surgery or radiation or both), restricted range of motion in the upper extremity (due to physical limitations, post-surgery recommendations, and/or pain avoidance), postural changes during treatment, and stress are all common after breast cancer treatment. As we saw above, changes in the normal use of the arm and shoulder can encourage the development of  long term side effects of breast cancer treatment. Likewise, they can spell trouble for the trapezius muscle too, contributing to overuse of the muscle and excess ‘tone’, which can initiate development of this syndrome.

Symptoms

Myalgia in the upper trapezius muscle can cause considerable muscle tension, soreness, and deep ache, and the muscle itself is usually very tender between the neck and shoulder when pressure is applied. There may be the feeling of ‘spasm’ of the muscle, and a limited range of motion in the neck is common.  Trapezius myalgia can also cause headache, in particular at the back of the head.

Diagnosis

This syndrome is diagnosed based on clinical findings, signs and symptoms. For example, the presence of painful trigger points in the muscle that when pressed cause a referral of pain, often to the back of the neck, shoulder, temple, or can feel like a headache behind the eye. In the absence of any other concerning ‘red flags’, no further testing or imaging is required to diagnose trapezius myalgia.

Treatment and Prevention

Since this condition is multifactorial, it responds best to a multifaceted approach to treatment.  Naturally, addressing the factors of stress, overuse, and reducing the amount of time spent in aggravating postures, can all bring meaningful improvement.

Treatments for trapezius myalgia

  1. Being as active as possible, particularly if your occupation involves a lot of sitting/desk work, as studies show that the more sedentary the individual, the higher the frequency of neck and shoulder dysfunction of this nature.
  2. Exercise Therapy. Studies show that specifically tailored strength training (for example 3x per week for 20 mins) results in more long-term benefits in pain reduction than general fitness training (ref 9). Valuable exercises include: one-arm-rows, reverse fly’s, shoulder shrugs, and lateral raises.
  3. Manual therapy. This includes ischemic compression, also known as trigger point release, stretching of the upper trapezius muscle, and transverse friction massage are all manual techniques that provide immediate pain relief.
  4. Dry Needling. Intramuscular stimulation (a type of acupuncture) has a positive impact on pain intensity and range of motion, in both the short and medium term (ref 10).
  5. Other modalities. There is some evidence to support the use of TENS, laser, and ultrasound for temporary pain relief in patients with trapezius myalgia (refs), so these might be considered.

How to prevent trapezius myalgia

  1. Maintain good shoulder and back strength through regular exercise, which has the added benefit of promoting good posture and shoulder biomechanics that have also been shown to be beneficial.
  2. Be careful not to be overly protective of your shoulder following breast cancer treatment, and seek treatment for any residual tightness or restriction across the chest, trunk, or armpit regions that you feel limit your full range of motion of the arm. This tightness can lead to overuse of the upper trapezius and neck muscles, and predispose you to trapezius myalgia.
  3. If you begin to experience pain in the neck or shoulder region, you may benefit from physiotherapy which should include manual therapy to address any trigger points that may be present, and to design an exercise program that will help you prevent further worsening of symptoms.

Other Upper Body Musculoskeletal Side Effects of Breast Cancer Treatment

There are several other upper body musculoskeletal disorders that are frequently observed side effects of breast cancer treatment. However, these disorders are a bit less common, or arise primarily in special populations or under specific circumstances. Some of the more common examples include:

Other forms of tendonitis in the arm

In addition to rotator cuff tendonitis discussed above, additional forms of arm tendonitis can arise as side effects of breast cancer treatment. These include tendonitis of the tendons of the elbow (Lateral Epicondylitis, or ‘tennis elbow’), thumb (De Quervain’s tenosynovitis) and biceps muscle (bicipital tendonitis), and they are typically caused by abnormal use or function of the shoulder.

Bone fractures

The side effects of breast cancer treatment can include bone loss and the related increased risk of bone fracture in women treated with anti-tumor drugs that are estrogen modulators.

Use of aromatase inhibitors to treat estrogen responsive breast cancer in postmenopausal women results in a precipitous drop in estrogen levels. Since estrogen has a protective effect on maintaining bone density, aromatase inhibitors can lead to a loss of bone density and resulting bone frailty. In fact, breast cancer patients treated with aromatase inhibitors have been shown to exhibit significantly greater bone loss and increased bone fractures compared to similar (‘matched’) breast cancer patients who were not treated with aromatase inhibitors (ref 8). In a similar manner, tamoxifen treatment in premenopausal women reduces estrogen activity and thus decreases bone density and predisposes otherwise healthy women to fractures and osteoporosis.

Patients treated with aromatase inhibitors or tamoxifen can help improve bone density through weight-bearing and balance exercises. This also offers the added benefit of decreasing risk of falls in the first place.

For more side effects of breast cancer treatment, please see: Top 4 Nerve Disorder Side Effects of Breast Cancer Treatment

References

  1. McCredie M.R., Dite G.S., et al. Prevalence of self-reported arm morbidity following treatment for breast cancer in the Australian Breast Cancer Family Study. Breast 2001;10:515-522.
  1. Manske R.C., Prohaska D. Diagnosis and management of adhesive capsulitis. Curr Rev Musculoskelet Med. 2008;1:180–189.
  2. Klc Z., Filiz M.B., Cakr T., Toraman N.F. Addition of Suprascapular Nerve Block to a Physical Therapy Program Produces an Extra Benefit to Adhesive Capsulitis: A Randomized Controlled Trial. Am J Phys Med Rehabil. 2015 Oct;94(10 Suppl 1):912-20.
  3. Uppal H.S., Evans J.P., Smith C. Frozen shoulder: A systematic review of therapeutic options. World J Orthop. 2015 Mar 18;6(2):263-8.
  1. Stubblefield M.D., Keole N. Upper body pain and functional disorders in patients with breast cancer. PM R. 2014;6(2):170-183.
  1. Hoogvliet P., Randsdorp M.S., Dingemanse R., et al. Does effectiveness of exercise therapy and mobilisation techniques offer guidance for the treatment of lateral and medial epicondylitis? A systematic review. Br J Sports Med 2013;47:1112–19.
  2. Dong W., Goost H., Lin X.B., et al. Injection therapies for lateral epicondylalgia: a systematic review and Bayesian network meta-analysis. Br J Sports Med. 2016 Aug;50(15):900-8.
  3. Mincey B.A., Duh M.S., Thomas S.K., et al. Risk of cancer treatment-associated bone loss and fracture among women with breast cancer receiving aromatase inhibitors. Clin Breast Cancer. 2006 Jun;7(2):127-32.
  4. Andersen L.L., Kjaer M., Sogaard K., et al. Effect of two contrasting types of physical exercise on chronic neck muscle pain. Arthritis Rheum. 2008 Jan 15;59(1):84-91.
  5. Liu L., Huang Q.M., Liu Q.G., et al. Effectiveness of dry needling for myofascial trigger points associated with neck and shoulder pain: a systematic review and meta-analysis. Arch Phys Med Rehabil. 2015 May;96(5):944-55.

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