Thoracic Cancers

Abstract

While a large variety of cancers in the thorax may be treated with radiation, many universal principles of skin care can be applied based on a thorough understanding of the treatment area and technical aspects of radiation delivery. For treatments using megavoltage photons treating lung parenchymal or mediastinal regions, skin reactions tend to be moderate. However, these skin-sparing effects can be negated if the overall field size is very large or if an excessive number of devices such as multileaf collimation are introduced into the beam pathway. In obese patients, more severe reactions may be observed due to larger amount of body surface area, the presence of skin folds, or an excessive number of monitor units that must be delivered through the surface to achieve the full amount of the dose prescribed to the deeply located targeted regions. Comorbid medical conditions may impede healing from acute tissue injury.

As hypofractionated treatments become more widespread, there will likely be some increase in both acute and late toxicities. Proton therapy poses a special risk of skin toxicity due to a typical arrangement utilizing fewer beams and the relatively higher percentage of dose deposited at the entry point of each beam. Other forms of particle therapy, such as neutron or carbon ion therapy, have also been associated with higher rates of skin toxicity.

Chemotherapy given concurrently in chemoradiation platforms has not generally been associated with increased skin reaction, but targeted therapies can produce independent and out-of-field reactions. In metastatic patients who start with radiation but later receive chemotherapy, recall phenomena may be seen with certain chemotherapy agents if they are given prior to radiation. Erlotinib and pemetrexed have both been reported in this context.

Most of the time, the management of skin reactions will require relatively simple interventions such as consideration of light cotton clothing or nontraumatic dressings. For patients who experience severe brisk erythema, cooling hydrogels should be used to increase comfort. Patients with itching should be given soothing emollients, and if the reaction is truly very severe, antipruritic medication can be prescribed or intermediate potency steroid creams may be required. The rare patients who demonstrate a very intense level of skin reaction are at risk for wet desquamation and should be monitored closely. For severe wet desquamation, control of potential skin infection and maintenance of an optimal healing wound environment are required.