Breast Cancer: Subtypes, Diagnosis and Newer Targeted Treatments

Breast cancer is broadly split into three types: hormone receptor positive, HER2 positive, and triple negative. The diagnostic procedure itself does not change based on subtype: a biopsy is still required, with mammography used only for initial evaluation. IHC testing on the biopsy sample determines ER, PR and HER2 status; if all three come back negative, the cancer is classed as triple negative, a more aggressive subtype that is harder to treat once it reaches stage four.

Neither is simply better in every case. MRI is the more definitive test to rule out cancer, but mammography, a form of X-ray, can miss a tumour hidden in fattier breast tissue, which is common in women under 30 to 35. In younger women, ultrasound or MRI is preferred; mammography becomes more effective after around 35 to 40, once fibrous tissue outweighs fat. MRI is more accurate but costlier and more involved for the patient, which is why mammography is offered first, with a PET-CT or a CT of the chest, abdomen and pelvis used for staging.

Immunotherapy is highly effective and carries far fewer side effects than standard chemotherapy. In cancers with a large initial tumour burden, such as lung cancer, it is usually combined with chemotherapy at first, since immunotherapy alone takes time to bring a heavy disease burden under control. Once the disease responds, treatment continues on immunotherapy alone to maintain that response.

Any scrotal swelling should first be evaluated with ultrasound, which will show a testicular mass or enlargement, but there is no test that gives a confirmed diagnosis before surgery, that only comes after radical orchiectomy. Of 100 patients presenting with a testicular swelling, roughly 80 to 90 percent will have cancer and about 10 percent tuberculosis, so for the large majority a biopsy is avoided, since it risks spreading the cancer, in favour of going directly to orchiectomy. Tumour markers such as AFP and beta-hCG, elevated in seminoma and yolk-sac tumours, can support the ultrasound finding, but the standard recommendation regardless of marker levels is orchiectomy rather than biopsy.

PSA is not specific for prostate cancer at all, no tumour marker is specific for any single cancer. An elevated PSA in a patient with a prostatic mass could reflect BPH or cancer, and can rise even after a digital rectal exam or ejaculation. Very high values, such as over 100, are more suggestive of cancer, so if PSA is extremely elevated yet the biopsy shows only BPH, the biopsy may simply have missed the cancerous core, which does happen. In such suspicious cases, a gallium-68 PSMA PET scan, highly specific for prostate cancer, can help confirm or rule out malignancy before treating for BPH alone.

Hormone receptor positive, HER2 positive, and triple negative, determined by IHC testing on the biopsy sample rather than by mammography.

Not as reliable. Mammography can miss a tumour in the fattier breast tissue common in women under 30 to 35, so ultrasound or MRI is preferred in that age group.

Started on a monoclonal antibody drug conjugate as first-line therapy, her brain metastases had completely disappeared on a repeat scan, and she remained well roughly a year and a half later without surgery or chemotherapy.