Targeted & Precision Therapy

What "targeted" actually means

Traditional chemotherapy attacks anything that divides quickly. That's why it hits cancer, but also hair follicles, the lining of the gut, and the bone marrow. Targeted therapy is different. It is designed to interfere with one specific molecule — a protein, a receptor, a mutated gene — that the cancer depends on to grow. If your tumour has that target, the drug usually works very well. If it doesn't, the drug won't help, and giving it anyway only causes side effects without benefit.

That's why we test the tumour first. The biopsy isn't only to confirm cancer — it's to find out what kind of cancer, and what its molecular fingerprint looks like.

"Twenty years ago, lung cancer was lung cancer. Today, it might be EGFR-mutant lung cancer, or ALK-rearranged, or KRAS G12C, or none of the above — and each one has a different first line of treatment. The biopsy report is half the diagnosis."

The role of molecular testing

Before we prescribe a targeted drug, we usually need a tissue sample — sometimes a fresh biopsy, sometimes the original surgical specimen — to look for specific changes in the cancer's DNA or in the proteins on its surface. In some situations a blood test ("liquid biopsy") can pick up these changes from circulating tumour DNA.

Testing takes time — usually 10 to 21 days for a full panel. We'll often start a "bridging" treatment while waiting for results, especially if the cancer is symptomatic. Once the results are in, we tailor the plan.

The two main shapes of targeted therapy

1. Oral tablets (small molecules, often called TKIs — tyrosine kinase inhibitors). Examples include osimertinib, alectinib, imatinib, sunitinib, lenvatinib, palbociclib, and many others. You take them at home, usually once or twice a day, often for years. There's no infusion, no clinic day — but the side effects need careful management at home.
2. Antibodies and antibody-drug conjugates (ADCs). Given as an infusion, like chemotherapy, but engineered to home in on a specific marker on the cancer cell. Trastuzumab, trastuzumab deruxtecan, sacituzumab govitecan, enfortumab vedotin, and others belong here. ADCs are sometimes described as "smart chemotherapy" — a toxic payload delivered directly to the cancer through an antibody.

What a typical treatment journey looks like

1. Biopsy and molecular testing are arranged — sometimes from a new biopsy, sometimes from existing tissue stored at the lab.
2. The results are reviewed together. We'll show you which marker was positive, what drug it points to, and what the evidence shows in terms of response rate and likely duration of benefit.
3. Treatment starts — either an oral tablet you collect from the pharmacy, or an infusion scheduled at the clinic.
4. The first follow-up is usually at two to four weeks — to check how you're tolerating it, manage early side effects, and adjust the dose if needed.
5. Scans are done every two to three months to see how the cancer is responding.
6. If the cancer eventually develops resistance — and most do, eventually — a repeat biopsy or liquid biopsy can show why, and often opens the door to a second-line targeted drug.

Common side effects — and what we do about them

Targeted drugs are generally better tolerated than chemotherapy, but they have their own personality. The side effects are usually predictable from the drug class.

• Skin rash — especially with EGFR inhibitors. An acne-like rash on the face and chest, often in the first weeks. Counter-intuitively, a brisk rash often signals the drug is working. Managed with gentle skincare, sunscreen, and sometimes a short course of doxycycline.
• Diarrhoea — common with many TKIs. Loperamide kept at home, taken at the first loose stool, prevents most problems. Persistent diarrhoea needs a dose review.
• Hand-foot syndrome — redness, peeling, and tenderness of the palms and soles, especially with capecitabine, regorafenib, and some TKIs. Moisturisers, soft footwear, and occasional dose reductions help.
• Fatigue — often present but usually mild enough to keep working.
• High blood pressure — with some anti-angiogenic drugs. Easily managed with a tablet, but needs monitoring.
• Liver enzyme changes, thyroid changes, blood sugar changes — picked up on routine blood tests and adjusted as needed.
• Heart effects — with HER2-targeted drugs and a few TKIs. We monitor heart function with echocardiograms during treatment.

What makes targeted therapy different from chemotherapy

Combination therapy — targeted plus something else

Increasingly, targeted drugs are not given alone. HER2-positive breast cancer is usually treated with two HER2-targeted drugs plus chemotherapy. Some lung cancers are treated with a TKI plus chemotherapy. Some kidney cancers combine a TKI with immunotherapy. The principle is the same: hit the cancer in more than one place at once, to delay resistance and deepen the response.

Cost and access — an honest conversation

Many targeted drugs are expensive, and not all are easily available in Pakistan. We'll be transparent about which drugs are accessible locally, which require import, whether a generic or biosimilar exists, and whether a manufacturer access programme can help. We'll also tell you honestly when a more affordable chemotherapy regimen would give a similar outcome — because financial toxicity is a real side effect too.

The bigger picture

Targeted therapy is one of the most exciting parts of modern oncology, but it isn't magic and it isn't universal. The first step is always the same: a good biopsy, the right molecular tests, and an honest conversation about what the results mean for you. Read about chemotherapy → or learn about immunotherapy →.