Radiation therapy is a common local treatment for breast cancer. While its beneficial effects have been found in the treatment of breast cancer itself, the potential long-term side effects deserve discussion; particularly those relating to possible onset of lymphedema and restricted shoulder mobility.

Lymphedema and limited shoulder mobility, as a result of radiation therapy, can be very challenging to deal with if proper treatment is not initiated in a timely manner.

It is important to understand and acknowledge these possible side effects of radiation therapy, so that if they do present, treatment can begin immediately.

Lymphedema Secondary to Radiation Therapy

Radiation therapy has the potential to disrupt the lymphatics in the area being treated, which commonly includes the affected breast, chest wall, and axillary lymph nodes.

Once damage has been done to the lymphatics, they are normally unable to re-grow or regenerate themselves. As a result, the lymphatics in the entire area treated are considered to be at a disadvantage.

While there can still be competent lymphatic vessels remaining after treatment, if the remaining vessels are unable to keep up with the normal workload in that area, then lymphedema may develop. This is a specific type of swelling that develops in the lymphatic vessels when the system in that area essentially becomes overwhelmed.

Lymphedema has the potential to develop in the treated arm, remaining breast tissue, and upper quadrant on the same side. If this occurs, the affected area typically becomes swollen, tight, heavy and can fatigue easily.

The above symptoms will naturally make it more challenging to use the arm. This makes it difficult to bend the arm, raise the arm overhead, or pick up objects.

The only effective treatment for lymphedema is Complete Decongestive Therapy (CDT). This involves manual lymphatic drainage (MLD), skin care, use of appropriate compression garments, and decongestive exercises.[1]


Restricted Shoulder Mobility Secondary to Radiation Therapy

While lymphedema is a potential side effect of radiation therapy, there are instances when restricted shoulder mobility can occur due to radiation alone, without the presence of lymphedema.

Radiation often causes abnormal changes to the skin, including development of firmness or fibrosis. This leads to tightened skin in the affected area, which can create pain when attempting to use the ipsilateral, or same side, arm. With this, any overhead motion or reaching away from the body will cause pain.

Another possible effect from radiation therapy is brachial plexopathy. This occurs from damage and injury to the complex of nerves that innervate the upper extremity. This can cause pain, impaired sensation, and/or abnormal functional use of the entire shoulder girdle.[2]

Commonly affected muscles negatively impacted from radiation may include the pectoralis group, latissimus dorsi, teres major, and possibly the rotator cuff muscles and trapezius. The extent of damage depends on the dosage and total amount of radiation treatments.[3]

Physical or occupational therapy can help address these challenges post-radiation therapy. While rehab is not able to completely reverse the effects of radiation, it can very much help with pain management and restoring functional use of the affected limb.


References

1. Shapiro, M.D. CL, Recht, M.D. A. Side Effects of Adjuvant Treatment of Breast Cancer. Wood, M.D. AJJ, ed. N Engl J Med 2001; 344:1997-2008. doi: 10.1056/NEJM200106283442607. Accessed September 29, 2022.

2. Senkus-Konefka E, Jassem J. Complications of Breast-cancer Radiotherapy. Clinical Oncology. 2006;18(3):229-235. doi:10.1016/j.clon.2005.11.004. Accessed September 29, 2022.

3. Lipps DB, Sachdev S, Strauss JB. Quantifying radiation dose delivered to individual shoulder muscles during breast radiotherapy. Radiotherapy and Oncology. 2017;122(3):431-436. doi:10.1016/j.radonc.2016.12.032.