Part two: biological cancer treatment and cutaneous reactions

Intracellular molecule inhibitors

Intracellular molecule inhibitors are a large group of biological drugs that impede the endocellular activities (multikinase inhibitors) that lead to cancer cell proliferation. The most widely used drug names include sorafenib, sunitinib, regorafenib, vemurafenib, selumetinib and everolimus. These drugs can cause symptoms that overlap those already described, in addition to causing other specific toxic effects such as that of hand-foot skin reaction (HFSR).

Hand-foot skin reaction (HFSR)

Hand-foot skin reaction (HFSR) is the most common side effect of biologic drugs. It occurs after the first two weeks of using the drug and may vary in severity. The first symptoms are localized redness and swelling, mainly at the sites of friction on the palms of the hands and the folds of the fingers. Redness and swelling of the hands may be accompanied by a burning sensation. Cases of hand-foot skin reaction should be evaluated according to extent and severity and, most importantly, how much it interferes with an individual’s normal daily activities.

In more severe cases, blisters may form. If the blister ruptures, serous fluid will leak out and, in the blister’s place, an area of thin, pink, very delicate skin will remain, which will return to normal within about a week with medication.

In some rare cases, skin redness is accompanied by the complete detachment of the stratum corneum (corneolysis), causing intense burning and the skin to become extremely red.

Plantar skin lesions have similar characteristics to palmar lesions. However, there is one important distinction between the two, which is the impact of pre-existing calluses on the sole of the foot. The skin produces calluses to protect itself in areas, such as the ball of the foot, where the body’s weight applies the most pressure during activities. These hard plaques are an excess of the stratum corneum and may be exacerbated by certain conditions (flat feet, osteoarthritis, hallux valgus, obesity, osteoporosis) that cause increased pressure or friction on the sole of the feet. Individuals who take biologic medications and who already have calluses on the soles of their feet are likely to develop blisters in the area of the plaque, which will cause the callus to swell and turn yellow. This discoloration is due to the detachment of the callous and the underlying part of the skin, which is then filled with fluid.

In more severe cases, the collection of fluid is so considerable that it leads to the formation of a blister which prevents the person from walking.

In cases of hand-foot skin reaction, the problem is caused due to biologic drugs partially inhibiting the formation of the junction apparatuses of epidermal cells. Junction apparatuses are structures made by cells that allow them to stay connected to each other. Without these apparatuses, the skin becomes fragile and damaged, particularly where pressure is applied, which is why the hands and feet are particularly affected.

Preventing hand-foot skin reaction

When considering preventive measures, it is important to consider the types of activities and work that the individual uses their hands for. For example, one can assume that manual laborers will more easily develop boils due to the fact the nature of their work exposes their fingers and palms to heavy pressures or frictions. Instead, when evaluating preventive measures for the feet, the presence of any calluses or imbalances on the sole of the feet need to be considered. Similarly, risks such as wearing hard shoes or regularly walking long distances also need to be taken into account.

Preventative measures for the hands

Before beginning any treatment, ensure the reason as to why hand-foot skin reaction has occurred has been established.

• Avoid carrying heavy loads whenever possible.
• Wash the hands with Eudermic Cleansing Base to maintain skin softness.

After each wash, apply Extreme Emollient Ointment to allow the skin to self-hydrate.

Preventive measures for the feet

Before beginning any treatment, ensure the reason as to why hand-foot skin reaction has occurred has been established.

• Assess the critical pressure points of the sole, which usually correspond to the presence of calloused areas.
• On callused areas, apply the exfoliating Glycocream+ every evening.
• Use wide, comfortable shoes preferably with a latex insole or other load-absorbing material.
• Wash the feet with Eudermic Cleansing Base to maintain skin softness.
• After each wash, apply Soothing Cream to allow the skin to self-hydrate.
• Wear breathable, preferably seamless, socks.

Managing hand-foot skin reaction

If hand-foot skin reaction appears despite the aforementioned preventative measures, the following recommendations should be adopted. At the first signs of redness or burning sensation in the hands, stop any manual labor whenever possible and apply Soothing Cream. At the first signs of irritation in the feet, only wear soft shoes with a latex insole and use breathable, seamless socks. Wash feet with Eudermic Cleansing Base and apply Soothing Cream after washing. If blisters form, contact your oncology treatment center in order to receive the most appropriate treatment advice (aspiration of the fluid and specific dressings). In such cases, it will be necessary to aspirate the liquid that has formed with a syringe. In the days that follow, the area can then be treated with PEG Balm, which will encourage the dead skin to peel off by itself when the new underlying is ready.