Chemotherapy Drugs and Combination Regimens, November 12, 1997

Chemotherapy Drugs and Combination Regimens, November 12, 1997

Chemotherapy drugs refer specifically to chemical agents used to treat cancer, broadly categorized into alkylating agents, alkaloids, metal compounds, and antibiotics.

1. Alkylating agents Nitrogen mustard (HN2), cyclophosphamide (CTX), N-formylmyricetin (N-F), thiotepa (TSPA), lomustine (CCNU), busulfan (BUS), procarbazine (PCZ), and nitrogen mustard derivative (DTⅠC). Nitrogen mustard derivatives form the basic structure of this class of chemotherapy drugs; other examples include carbazochrome and rocarbazochrome.

2. Heavy metal compounds Cisplatin (DDP), carboplatin (CBP).

3. Antibiotics Daunorubicin (DRN), doxorubicin (ADM), actinomycin D (ACD), mitomycin C (MⅠT), mitomycin (MMC), bleomycin (BLM), pingyangmycin (PYM), platinomycin (PLM), and camptothecin (EPT).

4. Alkaloids VCR (vincristine), etoposide (VP-16), colchicine (COL), and taxol (HR5).

5. Additionally, there is a class of drugs that specifically interfere with nucleic acid synthesis: fluorouracil (5-Fu), furan fluorouracil (FT-207), uft (UFT), mercaptopurine (6-MP), thioguanine (6-GT), hydroxyurea (HU), cytarabine (Ara-C), and cyclophosphamide (CC).

The basic functions of these five classes of chemotherapy drugs are as follows: ①Alkylating agents: directly participate in DNA synthesis, undergoing alkylation reactions that disrupt DNA formation. ②Heavy metal compounds: directly damage existing DNA. ③Antibiotics: act as DNA intercalators, inserting themselves into DNA and rendering it inactive. ④Alkaloids: affect protein synthesis, including nuclear protein synthesis and amino acid utilization. In addition to these four categories, the aforementioned 5-Fu, 6-MP, 6-GT, FT-207, MTX, Ara-C, CC, and HU directly interfere with nucleic acid synthesis.

Although these chemical agents each have their own basic functions, they target different phases of the cancer cell cycle. M phase (mitosis): vincristine, vinblastine, etoposide (VP-16), and colchicine (COL). In general, alkaloids belong to this category and directly inhibit cell division because they primarily affect albumin synthesis, including nuclear protein and amino acid synthesis. S phase (DNA synthesis phase): 6-MP, 5-Fu, 6-GT, FT-207, MTX, Ara-C, CC, and HU, mainly inhibiting nucleic acid synthesis. To master the general principles of chemotherapy, one must understand that most alkylating agents, antibiotics, and heavy metal salts are non-specific chemotherapy drugs.

Based on the properties of these drugs, it is common to combine a non-specific drug like CTX with an M-phase drug like VCR in a chemotherapy regimen: for adenocarcinoma, add 5-Fu and MMC; for squamous cell carcinoma, add ADM, DDP, and CBP; for undifferentiated lung cancer, add VP-16; for head and neck cancer, add PVM; for melanoma, add DTⅠC; for brain metastases, add CCNU and MTX; for ovarian, breast, and bladder cancers, add TSPA; for testicular cancer, add N-F; for lymphoma, add PCB; for multiple myeloma and seminoma, add PAM. CTX is typically administered at 800–1000 mg once a week; VCR at 2 mg once a week; ADM at 40 mg every three weeks.